Humans show many asymmetries. Heart, lungs, liver and other viscera are either to one side, or differ on the two sides, and most people also have an asymmetric brain, with a majority of people being right-handed and having language processing in the left hemisphere of the brain. In this talk I will look at some recent advances in our understanding of the biology of asymmetry.

Aside from a few major successes, there have been many problems replicating significant associations between polymorphic gene variation and complex diseases. There are several reasons for this, of which population structure is widely considered to be the most important. Population structure will affect both the validity and power of experiments and may be particularly important when relative risks are slight or the alleles involved are rare. With low relative risks and/or rare alleles, sample sizes need to be much larger than those often used in case-control studies and as sample size increases, the amount of population structure needed to perturb the results decreases. To address this problem, there are several statistical methods available that attempt to allow for the effect of population structure to be taken into account.

However, these methods are not really satisfactory and so the only suitable alternative is to design the studies with greater care and a powerful approach may be to characterise genetically both the cases and controls. Individuals from the controls can then be chosen to match the cases so as to minimise the stochastic differences between the two populations. We are therefore assembling a UK control population as a resource for future studies. It will comprise samples from 3500 individuals, who will have been carefully selected from throughout the UK. Rural regions will be targeted to avoid the admixture observed in large urban environments and volunteers will be sought who were born in the same place as their parents and grandparents to ensure historical integrity. The collection will be genotyped for around 3000 markers, with the aim of identifying about 200 ancestrally informative markers (AIMs). These AIMs will then be used to match controls to cases.

Background: The intervertebral disc and spinal ligaments contain extensive and well organised elastic fibre networks which provide these tissues with elasticity. Morphologically elastic fibres are composed of an amorphous central core consisting mainly of elastin surrounded by a microfibrillar mesh. The importance of the microfibrils has been emphasised by the clinical manifestations of Marfan Syndrome (MFS) and congenital contractual arachnodactyly (CCA) which are caused respectively by mutations of Fibrillin-1 and Fibrillin-2, the main protein components of the microfibrillar mesh. Both patients of MFS and CCA can develop a spinal deformity. Recent studies on genetically modified mice suggested that minor components of the microfibrillar mesh can also play an important role in spine development; knockout mice containing no fibulin-5, microfibrillar associated glycoprotein-2 (MAGP-2), or latent TGF-b protein 3 (LTBP-3) can all develop spinal deformity. Our aim in this study was to understand the involvement of elastic fibre system in pathogenesis of scoliosis.

Methods: Tissue from Marfan patients and adolescent idiopathic kyphoscoliotic human intervertebral discs were removed during routine surgery with consent and ethical permission. Here we report on examination of disc tissue from three Marfan’s syndrome and three AIS patients (with ethical approval), age range 13–33 years. Tissues were dissected and then snap frozen within 4 hours after surgical excision and kept in −80 OC till used. Tissue sections of 20 micron were cut with a cryostat microtome and fixed with 10% formalin before immunostaining. Microfibrils and elastin fibre network were studied by immunostaining fibrillin-1 and elastin. The collagen network was examined by using fluores-cent microscopy with a polarised light system. Spines from transgenic mice, producing no elastin or fibulin-5, were paraffin embedded and sections were stained with Haematoxylin & Eosin or Alcien Blue. The morphology of cells, vertebral body and disc matrix were studied at light microscopic level.

Results and Discussion: Our histological studies on IVD tissues from MFS and AIS patients found that the elastic fibre and collagen networks were disorganised compared to that of normal controls. Studies on spines from fibulin-5 null or elastin null mice indicated delayed ossification of the vertebral body, lower expression of proteoglycans and an abnormal growth plate. Our initial results thus indicate that the elastic fibre system has an effect on matrix synthesis in connective tissue and plays a part in regulating bone growth. They are in agreement with reports that kypho-scoliosis occurs in transgenic mice deficient in other matrix components e.g. collagen-II and perlecan. Matrix-generated regulation of spine development and vertebral body growth thus appears to play an important role in the development of scoliosis.

Aim: This study tested quantitatively whether calculated loading asymmetry of a spine with scoliosis, together with measured bone growth sensitivity to altered compression could explain the observed rate of scoliosis progression during adolescent growth. Scoliosis is thought to progress during growth because angular deformity produces asymmetrical spinal loading, generating asymmetrical growth, etc. in a ‘vicious cycle’.

Materials and Methods: The magnitude of asymmetrical spinal loading was estimated for a spine with scoliosis, assuming physiologically plausible muscle activation strategies. In animal studies of vertebral and tibial growth plates of three different species, the growth plate response to sustained compression was measured and correlated with histological measures of chondrocytic proliferation and hypertrophic enlargement. These data were expressed in a linear formulation of growth G as a function of compressive stress, thus:

G = Gm(1-β(_-_m)); where β=1.68 MPa-1 was the empirically determined constant. (The subscript m signifies the ‘baseline’ growth and physiological stress).

The vertebral and discal contributions to human adolescent spinal growth velocity were measured from stereo-radiographs of 208 patients of with scoliosis. The estimates of level-specific spinal loading asymmetry, together with the relationship expressing growth sensitivity to load were included in an analysis that was used to estimate the resulting asymmetrical vertebral growth, and its contribution to the progression of a scoliosis curvature. The initial geometry represented a lumbar scoliosis of 26° Cobb, averaged and scaled from measurements of fifteen patients’ radiographs. Spinal growth during each of the adolescent years was estimated from growth curves obtained from cross-sectional logistic-correlation of the radiographically determined spinal and vertebral heights versus age.

Results: The analyses of mechanically modulated growth of the spine with an initial 26° Cobb scoliosis predicted curve progression for the majority of eleven loading conditions (effort magnitude and direction) that were analysed. The averaged final lumbar spinal curve magnitude was 34° Cobb at age 16 years when the efforts producing the spinal loading were at 50% of maximum effort, and it was 42° Cobb when the efforts were at 75% of maximum.

Conclusions: An analysis that included analytically determined spinal load asymmetry and empirically determined growth sensitivity to load predicted that a substantial component of scoliosis progression during growth is biomechanically mediated.

Clinical Relevance: The rationale for conservative management of scoliosis during skeletal growth assumes a biomechanical mode of deformity progression (Hueter-Volkmann principle). The present study provides a quantitative basis for this previously qualitative hypothesis. The findings suggest that an important difference between progressive and non-progressive scoliosis might lie in the differing muscle activation strategies adopted by individuals, leading to the possibility of improved prognosis and conservative interventions, as well as treatments employing early minimally invasive localised growth modulation or arrest.

Introduction: Vertebral rotation is an important aspect of spinal deformity in scoliosis, associated with ribcage deformity (rib hump). Although both lateral curvature and axial rotation appear to increase together in progressive scoliosis, the mechanisms driving vertebral rotation are not clearly established and it is not known whether lateral curvature precedes rotation, or vice versa. This study investigates the hypothesis that intravertebral (within the bone) rotation in idiopathic scoliosis is caused by growth in the presence of gravity-induced torsions, the twisting moments generated by gravitational forces acting on the scoliotic spine.

Methods: The twisting moment Tp acting at an arbitrary point P on a three-dimensional spinal curve is given by Tp=Mp·â, where Mp=r¥F is the total moment due to gravity force F acting at (vector) distance r, and â is the tangent to the spinal curve at P (Figure One). Standing radiographs for five idiopathic scoliosis patients were used to define three-dimensional curves representing the approximate axes of rotation of each spine, running along the anterior edge of the neural canal from T1 to S1. The equilibrium equations above were then solved to calculate gravity-induced torsions exerted by head and torso weight about the spinal axes for each patient. Intravertebral rotations were measured for the same patients using Aaro & Dahlborn’s technique with reformatted computed tomography images in the plane of superior and inferior endplates of each vertebra. The gravity-induced torsion curves were compared with intravertebral rotation measurements to see whether gravity-induced torsion is a likely contributor to intravertebral rotation.

Results: Gravity-induced torques as high as 4 Nm act on the spines of idiopathic scoliosis patients due to static body weight in the standing position. Maximum intravertebral rotations (for a single vertebra) were approximately 78. There appears to be general agreement between the measured intravertebral rotations and profiles of gravity-induced torsion along the length of the spine (Figure 2). Rotation measurements confirm the finding of previous authors that maximum intravertebral rotations occur at the ends of a scoliotic curve (with little relative rotation at the apex), and this finding is consistent with the gravity-induced torsion profiles calculated.

Conclusion: Gravity-induced torsion is a potential cause of vertebral rotation in idiopathic scoliosis. Since the spine must be curved in three-dimensions (out of plane) to produce such torques, vertebral rotation would be expected to occur subsequent to an initial lateral deviation, suggesting that coronal curvature ‘drives’ axial rotation during scoliosis progression.

Objective: To clarify whether serum melatonin levels in adolescent idiopathic scoliosis correlate with curve progression, and whether the exogenous melatonin treatment is effective in patients with decreased levels of endogenous melatonin in adolescent idiopathic scoliosis.

Method: A total of 63 adolescents were studied; 38 with adolescent idiopathic scoliosis and 25 age matched control subjects. We divided the patients into stable (28 patients) and progressive (10 patients) groups based on the scoliotic curve measured radiographically at three to six month intervals. The level of melatonin was considered low if it fell below the mean – 2.0 standard deviation established in normal adolescents throughout the 24 hour period or nocturnal (0:00 – 6:00 hour) integrated concentration. Oral melatonin replacement (3mg / before bedding) was administered in patients with decreased endogenous melatonin. The patients with low melatonin were treated with a brace, melatonin or both combined. During melatonin treatment, the level of melatonin was measured yearly for a period ranging from three to six years.

Results: In all subjects the melatonin levels showed diurnal variations; low during the day and high at night. Of 38 patients with adolescent idiopathic scoliosis, 22 patients had normal melatonin and 16 had low melatonin. Of 22 patients with a normal melatonin, 10 of 15 treated with brace and 6 of 7 untreated patients had stable scoliosis, and the remaining six had a progressive scoliosis. Of 16 patients with low melatonin, eight of nine treated only with melatonin, and four of seven treated with melatonin and brace had stable scoliosis. The remaining four had a progressive course. Of the 10 patients who had progressive scoliosis in normal and low levels of melatonin, nine had greater than 40 degrees of curve at the initial examination.

Conclusion: These findings suggest that transient melatonin deficiency may be associated with deterioration of scoliosis and that melatonin level may serve as a useful predictor for progression of spine curvature in patients with idiopathic scoliosis. Also, the results of this study suggest a possible role of melatonin supplement in the prevention of progressive scoliosis especially in mild cases showing less than a 40° curve.

Supported by the Fondation Yves Cotrel, Institut de France.

Problems of vertebral growth plate metabolism regulation at different stages of ontogenesis are insufficiently covered in the literature. However, the study of function mechanism of provisional cartilage of vertebral growth plate is a practical and theoretical basis of pathogenesis model of idiopathic scoliosis and Scheuermann’s disease both associated with growth disorders.

Objective: To investigate the function mechanism of vertebral growth plate structural components during formation and growth.

Materials and methods: Fifty vertebral body specimens of children at the age from 1 to 14 years obtained from the forensic medicine department were studied by methods of morphohistochemistry, biochemistry, and ultra-structural analysis. The expression of five proteoglycan genes and their albuminous products was investigated by RT-PCR method.

Results: The process of growth represents a sequence of morphogenetic movements ongoing up to the achievement of sexual maturity. But morphofunctional organization and regulation of growth are different in different periods of ontogenesis. Early postnatal growth of vertebral bodies is governed by a radially located zone of growth. The cell population in a just-formed cartilage growth plate is non-uniform: from poorly differentiated chondroblast through the form of highly differentiated ones to degrading chondrocyte. This period of the spine development is characterised by the presence of vessels in provisional cartilage tissue. The concept of “chondro/hematic barrier” suggested and validated by A.M Zaidman explains a conservation of homeostasis at a stage of vertebral bodies differentiation. The process of chondrogenic differentiation of prechondroblasts in the early postnatal period is inducted by the chorda influence. In the late postnatal period (12–14 years) the laws of structural and functional organization of cartilage growth plate of vertebral body remain the same: phenotypic heterogeneity, polarity, and zonality of cells. A metabolic centre of complex architectonics of cartilage tissue is chondroblast. Chondroblast is functioning at the level of chondron which is a functional unit of vertebral growth plate. Chondroblast (chondrocyte) is located in the centre of chondron and surrounded by pericellular matrix presented by diffuse aggrecan molecules, or growth plate aggregates.

Due a peculiar architectonics, growth plate molecules have inner spaces comparable in size with Golgi’s vesicles. Metabolites, small molecules, and water freely penetrate through these molecules. Diffuse molecules together with type II thin collagenic fibres, minor collagenes, and structure-forming growth plates perform barrier function. Besides barrier function, diffuse molecules perform information function inside a chondron, forming a kind of information field. Signals of this field are perceived by chondroblast receptors, and the cell gene apparatus expression is carried out through second messengers. Thus, either stimulation of proliferative activity with subsequent differentiation during intensive growth, or interruption of these processes (period of growth delay) occurs. Single chondrons unite into chains in proliferation zones. Cell interaction inside chondron occurs due transmembrane structures, as a contact coordination of functions of cells with inherent high specificity. Concentration of diffuse molecules of growth plate (aggrecan) in proliferation zones is the highest on evidence of histochemical and ultrastructural assays. Besides, diffuse molecules are the short-distance regulators of DNA synthesis the mechanism of action of which is realised through the system of receptors on a cellular membrane. Hence, contact intercellular interactions are one of the mechanisms controlling cell division. These are so-called extracellular factors of chondroblast proliferation regulation.

Thus, the process of growth represents a complex two-stage mechanism of proliferation and differentiation of chondroblasts, and adequate osteogenesis. All three processes provide harmonious spine formation, and disturbance of one of them results in pathology development.

Introduction: Loads acting on scoliotic spines are thought to be asymmetrical and involved in progression of the scoliotic deformity. Abnormal loading patterns could lead to changes in bone and disc cell and activity and hence to vertebral body and disc wedging. At present however there are no direct measurements of intradiscal stresses or pressures in scoliotic spines.

Methods: Stress profilometry was used to measure horizontal and vertical stresses at 5mm intervals across 25 intervertebral discs of 7 scoliotic patients during anterior reconstructive surgery. Identical horizontal and vertical stresses for at least two consecutive readings defined a region of hydrostatic pressure. Results were compared with similar stress profiles measured during surgery across 10 discs of 4 spines with no lateral curvature and with data from the literature.

Results: Profiles across scoliotic discs were very different from those measured across normal discs of a similar age. Hydrostatic pressure regions were only seen in 16/25 discs, extended only over a short distance and were displaced towards the convexity. Mean pressures were significantly greater (0.24MPa) than those measured in other anaesthetised patients (< 0.06 MPa). A stress peak in the concave annulus was a common feature (13/25) in scoliotic discs. In 21/25 discs, stresses in the concave annulus were greater than in the convex annulus, indicating asymmetric loading in these anaesthetised, recumbent patients.

Conclusions: Intradiscal pressures and stresses in scoliotic discs are abnormal even in the absence of significant applied load. Disc cells respond to changes in pressure, hydration and deformation by altering matrix synthesis and turnover in vivo and in vitro. Hence, whatever the cause of the abnormal pressures and stresses in the scoliotic discs, if present during daily life, these could lead to disc matrix changes and especially if asymmetrical, to disc wedging and progression of the scoliotic deformity.

Work supported by Fondation Cotrel

Introduction: Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis, which appears to be caused by a melatonin signalling dysfunction proved recently in osteoblasts. This pathology occurs and progresses during the time of pre-puberty and puberty growth. This period is known to be under the hormonal control and coincides with many biological changes related to the secretion of estrogens, of which estradiol (E2) is the most active. The female prevalence of AIS disease is clearly evident. Indeed, in Quebec the spine deformities considered clinically significant (at least 11° of deformity) are found in a girl:boy ratio of approximately 2:1 for reduced scoliosis, and this ratio increases to 10:1 for scoliosis of more than 30o of deformation. However, the reason for this female prevalence as well as the role of estrogens and estrogen receptors in AIS is not clear despite the fact that these hormones are known for their impact on bone and bone growth, including the spine.

The purpose of the present study was to investigate the role of E2 on the responsiveness of the AIS cells to the melatonin, to determine the expression of estrogens receptors (ERα and ERβ) in AIS tissues and to clarify the impact of estrogen receptor gene polymorphisms in the pathogenesis of AIS.

Methodology: The effects of oestrogen on the AIS osteoblasts (n=10) response to the melatonin was determined by measuring the reduction of forskolin-induced cAMP accumulation. The forskolin treated osteoblasts were incubated in the presence of increasing amounts of melatonin (10–11 to 10-5 M) with or without physiological concentrations (10-10 M) of 17-β-estradiol for 16 hours, and the intracellular cAMP measured by radio-immunoassay using Biotrak Kit. Using RT-PCR, we determined ERα and ERβ mRNA expression in osteoblasts from AIS patients (n=14). Polymorphisms of the first intron of the ERα gene, which contains the XbaI and PvuII polymorphisms, were investigated by PCR following digestion with restriction enzyme and using the genomic DNA from lymphocytes isolated from scoliotic patients (n=33). Using the restriction enzymes XbaI and PvuII, the allelic variants XX, Xx, xx, PP, Pp, and pp were identified in 33 AIS patients (uppercase letters represent absence, and lowercase letters represent presence of restriction sites).

Results: The intracellular level of cAMP was significantly increased (p< 0.01) in the presence of a physiological concentration of 17-β-estradiol (10-10 M) when compared to the level observed in the presence of melatonin alone (10-9 M) (melatonin + estradiol: 109.46 ± 20.07; melatonin 76.09 ± 12.32 (mean ± SD)). As previously described by Dr Moreau’s team, the same pattern (three type of response to melatonin) takes place in the presence of 17-β-estradiol. We observed the loss of ERβ gene expression in 8/ 14 AIS patients contrasting with ERα gene expression that was found in all AIS patients. The XbaI and PvuII polymorphisms were found in 70% (23/33) and 80% (26/33) of the cases respectively. Of the 33 cases, 21 presented both digestion sites, 24 presented PvuII digestion site (6 homozygote, 18 heterozygote) and 23 (8 homozygote, 15 heterozygote) presented XbaI digestion site. The allelic variants were found as follows: XX: n=8, Xx: n=15, xx: n=8, PP: n=6, Pp: n=18 and pp: n=6. Classified by their location in the spine, seven right thoracic, one left thoracic, one right thoracolumbar, three left thoracolumbar and nine right thoracic-left lumbar were found among the patients presenting PvuII positive polymorphism. Among the patients with XbaI positive polymorphism, six right thoracic, one left thoracic, one right thoracolumbar, three left thoracolumbar and eight right thoracic left lumbar were found.

Conclusion: These results show the antagonistic effects of the 17-β-estradiol on AIS osteoblasts response to the melatonin. Thus estrogens interference with melatonin signalling activity would act as a triggering or aggravating factor in the pathogenesis of AIS. At the molecular level, it is possible that estrogens attenuate the response of AIS cells to melatonin through the desensitization of melatonin receptors. The loss of ERβ expression in a significant number of AIS patients appears to be important for the change of the ERα/ERβ receptors ratio that consequently may perhaps alter estrogens signalling pathways. The XbaI and PvuII polymorphisms are present in a significant number of AIS patients but this was not dependant of the curve pattern. These results clearly support the interplays and crosstalk between estrogens and melatonin signalling pathways in AIS aetiopathogenesis.

Supported by the Fondation Yves Cotrel, Institut de France

Introduction: Experimental pinealectomy in chickens shortly after hatch produces scoliosis with morphological characteristics similar to that of human idiopathic scoliosis (Coillard et al., 1996). The objective of this study was to develop a finite element model (FEM) incorporating vertebral growth to analyse how bone growth modulation by mechanical loading affects development of scoliosis in chicken.

Materials and Methods: We have adapted the experimental set-up of Bagnall et al. (1999) to study spine growth of pinealectomised chickens. Three groups were followed for a period of six weeks:

wild-type (controls) (n=25);

The experimental data was used to adapt a FEM previously developed to simulate the scoliosis deformation process in human (Villemure et al. 2002). The FEM consists of 7 thoracic vertebrae and the first lumbar, the intervertebral discs and the zygapophyseal joints. The geometry was measured on specimens using a calliper. The material properties of human spines were used as initial approximation. The growth process included a baseline growth (0.130 mm/day) and a growth modulation behaviour proportional to the stress and to a sensitivity factor. It was implemented through an iterative process (from the 14th to the 28th day). Asymmetric loads (2–14 Nmm) were applied to represent different paravertebral muscle abnormalities influenced by the induced melatonin defect.

Results: Within the pinealectomised group, 55% of the animals (n = 42) developed a scoliosis. In the FEM model, by varying the value of the applied moment, different scoliosis configurations were simulated. The resulting Cobb angle varied between 6° and 37°, while the maximal vertebral wedging appeared at T4 or T5 (range between 5° to 28°). A descriptive comparison of the simulation results with the experimental deformation patterns (n = 41; mean Cobb angle: 26°) was made as a preliminary validation. In 2 typical cases, the scoliotic shapes were quite similar to that seen in the scoliotic chickens.

Discussion and Conclusion: The basic mechanisms by which the metabolism of the growing spine is affected by mechanical factors remain not well known, and especially the role of tissue remodelling and growth adaptation in scoliosis. The agreement between the experimental study and preliminary simulation results shows the feasibility of the model to simulate the scoliotic deformation process in pinealectomised chickens. When completely developed and validated this modelling approach could help investigating the pathomechanisms involved in the scoliotic deformation process. Especially, computer simulations could be used to complement bio-molecular and mechanobiological studies concerning the neuroendocrinal hypothesis implicating melatonin signalling dysfunction, which could trigger a complex cascade of molecules and mechanoreceptors leading to an accumulation of specific factors in specialised tissues (Moreau et al. 2004), directly or indirectly implicated in proprioception, and which can be implicated in the pathomechanisms of scoliotic deformities.

It is accepted that the development of scoliosis has a close relationship with physical growth, but the aetiology and mechanism of the disease remain unknown. Few studies have assessed the bone microarchitecture and histomorphological findings in vertebrae. After the occurrence of scoliosis, those include secondary changes caused by mechanical compression. It is important to investigate those data in the period prior to the occurrence of scoliosis.

Methods: Study One: One hundred female Broiler chickens were divided into 3 groups: the control group (n=20), the sham operation group (n=20), and the pine-alectomy group (n=60). Then the pinealectomy group was divided into three groups according to the time of sacrificing: one week after the operation (Group P-1w, n=20), two weeks and three weeks after the operation respectively (Group P-2w and 3w, n=20 respectively). Using microCT, the bone volume (BV/TV), trabecular thickness (Tb.Th), the number of trabecular (Tb.N), and trabecular separation (Tb.Sp) of the concave and convex sides of the apex vertebrae in the scoliotic chickens were determined.

Study Two: Sixty female Broiler chickens were divided into three groups: the control group (group C, n=20), the sham operation group (group S, n=20), and the pinealectomy group (group P, n=20). Each group was then subdivided into two groups according to the time of sacrificing: 3 days after the operation (group 3-C, 3-S, 3-P, n=10), and six days after the operation (group 6-C, 6-S, 6-P, n=10). Decalcified thin sagittal sections were made using a tartrate-resistant acid phosphatase (TRAP) stain. Histological examinations of the growth plate, trabecular structure and osteoclast number were performed.

Results: Study One: The incidences of scoliosis in the pine-alectomised Broiler chickens was 84.2% (Group P-1w), 88.9% (Group P-2w) and 89.5% (Group P-3w) respectively, and Cobb angles were averaged 11.6, 14.6 and 21.2 degrees respectively. There was no obvious wedging deformity of vertebrae in the groups. Only in Group 3w, the BV/ TV, Tb.Th and Tb.N of the concave side were significantly greater than those of the convex side.

Study Two: Nine out of ten chickens in group 6-P showed scoliosis deformity, while the presence of scoliosis was unclear in any of chickens in group 3-P. The osteoclast number increased significantly in group 3-P, compared to groups 3-C and 3-S, and the trabecular thickness was greater in group 3-P than in groups 3-C and 3-S. There was no significant change in the growth plate or in other aspects of the trabecular structure, except for trabecular thickness, in any of the groups.

The results of study one showed that the change of microarchitecture might be caused by Wolff’s law and was the secondary response to the scoliotic deformity. Therefore, it was difficult to clarify the cause of scoliosis using micro CT. In study 2 we found that the number of osteoclast increased in pinealectomised chickens after 3 days postoperatively, just before scoliosis began to develop. We also found there was no change in the growth plate. These outcomes suggest that there are no relationships between changes in the growth plate and the development of scoliosis. However, the change in osteoclast number may have a relationship with the development of scoliosis through changes in bone modelling.

Background: Low bone mass in patients with adolescent idiopathic-scoliosis has been well reported in cross-sectional studies. No large-scale longitudinal-study has been conducted to track bone-mineral-density (BMD) trajectory in peripubertal AIS with varying scoliosis-severity.

Aim: We evaluated the BMD trajectory and factors determining BMD accretion in AIS during peripubertal period.

Method: One hundred and ninety-six newly diagnosed AIS girls with Cobb-angle > 100 and 122 healthy girls, aged 12–15 years were followed-up for two years. Weight, height, leg length, menarche and Cobb-angle were determined. Areal lumbar-spinal BMD (LSBMD) and femoral-neck BMD (FNBMD), and volumetric distal-tibial BMD (TiBMD) were evaluated by dual-energy-x-ray-absorptiometry and peripheral QCT respectively. BMD growth-models were fitted by multilevel modelling (mixed longitudinal design).

Results: At baseline, 93% participants were pre-menarchial or within three years of menarche. Average Cobb-angles at baseline and subsequent follow-ups were 260, 230 and 260 respectively. TiBMD of AIS (moderate- and severe-severity) was significantly lower than the controls from 13–16 years (ANOVA, P< 0.05). Posthoc-test showed that TiBMD of severe-AIS was lower than moderate-AIS at 15–16 years (P< 0.05). LSBMD accrual was significantly lower among AIS (moderate- and severe-severity) than the controls from age 13–17 years (ANOVA, P< 0.05). FNBMD of AIS (moderate- and severe-severity) was lower than the controls at 15 years (ANOVA, P< 0.05). BMD trajectories of individuals differed inter-personally and intra-personally over time and that BMD growth followed a curvilinear pattern. The rates of BMD accretion reduced with retarded growth across peripubertal-period. Weight and height were significant time-varying predictors on BMD growth. BMD of AIS was persistently lower than the healthy girls throughout the study (P< 0.05).

Conclusions: This large-scale longitudinal study in AIS girls with moderate to severe-curve-severity showed for the first time that both the volumetric and areal BMD were persistently lower when compared to the age-matched healthy girls throughout 12–17 years. AIS with more severe curve-severity were found to have much lower BMD throughout the peripubertal period. Promotion of a higher bone-mass is important for AIS to modify scoliosis-progression and to achieve peak bone mass in order to reduce the risk of osteoporosis later in life.

Background: Adolescent Idiopathic Scoliosis is a 3-dimensional deformity of the spine affecting peri-pubertal adolescents (10-17-y) mostly. Although generalised osteopenia is well documented in AIS, the patho-physiology of AIS related osteopenia is uncertain.

Aim: We studied the association between pubertal-growth, BMD, bone-turnover, calcium intake (CA) and physical-activity (PA) in AIS and compared to those of healthy girls.

Methods: 894 girls (594 AIS & 300 healthy controls) aged 11–16-y entered the study. Anthropometric parameters, areal-BMD of the proximal-femur and volumetric-BMD of the distal-tibia were determined by Dual-x-ray-Absorptiometry and peripheral QCT respectively. Bone-turnover-markers: bone-alkaline-phosphatase (bALP) and deoxypyridonine (Dpd) were assayed. CA and weight-bearing PA were assessed by FFQ method.

Results: Weight of AIS at < 12-y and 13-y was significantly lower than controls (P< 0.05). From 13-y, corrected right and arm-span of AIS were significantly longer than the controls (P< 0.02). aBMD and vBMD were 6.7% and 8.4% respectively lower than the controls across the ages (P< 0.05). The disparity in BMD compared with controls increased with age. CA was not different between the AIS and controls (361 mg/d, IQR:230–532mg/d vs. 319 mg/d, IQR:220–494mg/d; P=0.063). Weight-bearing PA of AIS was significantly lower than those of controls (P< 0.02).

CA of AIS and controls reached < 40% of the Chinese calcium DRI (1000 mg/d). Both CA and weight-bearing PA were correlated with BMD in AIS (P< 0.04 & P=0.002 respectively). Both CA and PA were independent predictors on the variations of aBMDs (P< 0.03) and vBMDs (P< 0.04) in AIS after controlling for confounders in multivariate analysis. Regarding bone turn-over rate, bALP in AIS was 38.6% higher than the controls from 13-y onwards (P< 0.005) while Dpd of AIS was 30.4% lower than controls at age 15-y (P=0.003). Furthermore, bALP in AIS was negatively correlated with age-adjusted BMD (r=−0.34, P< 0.001) while the correlation was weaker in the controls (P=0.14, P< 0.002).

Conclusion: The correlation of calcium intake and physical activity with BMD occurred predominantly in AIS only and that these two factors were also independent determinants on BMD of AIS implying that calcium intake and physical activity were significant modulators on BMD in AIS. Significantly faster physical-growth, higher bone formation rate were associated with lower BMD. Osteopenia in AIS could be interplayed by abnormally faster pubertal-growth and bone-turnover. In fact, Calcium intake of AIS was too low to meet the calcium demand for bone-mineralization. A controlled calcium supplementation and programmed physical activity intervention trial is merited to confirm the effect of Calcium intake and physical activity on bone acquisition in AIS at peripubertal period.

The assessment of vestibular function throws new light on scoliosis. Vestibular morphological anomalies are frequent in scoliosis. This communication has two aims:

to correlate the dysfunctions of the semi-circular canal system with morphological anomalies.

These anomalies are demonstrated by graphic modelling from MRI images (see abstract of Dr. Rousié). The examination of the proprio-oculo-labyrinthine system is done by Videonystagmography (VNG) and Videooculography (VOG). We able to test both horizontal and vertical canal function to give a 3D vestibular assessment. We use these tests to measure primitive vestibular dissymmetry (PVD). We compare the 3D endolymphatic morphology with the 3D vestibular function.

Results: The study comprises more than 100 cases. Inclusion criteria: scoliosis and cranio-facial asymmetry (CFA); Exclusion criteria: previous history of vestibular pathology or head injury.

In the horizontal plane the correlations are: with caloric test over 80%; with kinetic test around 70%;

In the vertical plane the correlation is around 70%. The figures will be detailed in the communication.

The difference between the results obtained with the caloric test and the kinetic tests is in connection with the phenomena of central compensation. On the vestibular level there is a close connection between the scoliosis, the vestibular morphological anomalies and the vestibular examination.

Clinical application: We proceed systematically to a vestibular assessment, even in absence of vestibular complaints or disequilibrium. We have found in certain cases where there has been a poor response to treatment or a defect of compliance, there has been an anomaly of vestibular function. After vestibular rehabilitation we observe an improvement of the effectiveness and acceptance of the treatment. We analyse the proprio-oculo-labyrinthin system by VNG, VOG, fundus (asymmetry of static ocular torsion) and the vestibulo-spinal system by posturography. The main anomalies concern vertical semi-circular canals function, otolithic system and vertical ocular smooth pursuit. The vestibular rehabilitation rebuilds a coherence between these three systems. This is possible in the child of more than six years. For us the vestibular assessment and vestibular rehabilitation are the first step of the management of the treatment.

The vestibular assessment and vestibular rehabilitation are necessary because of the close connections between the anomalies of the proprio-oculo-labyrinthin and the scoliosis.

Analysis of balance is emerging as an important parameter in spinal deformity. Force plate technology permits a quantitative study of balance through centre of pressure (COP) measurement. COP measurements obtained from the force plate approximate the projected centre of gravity. In a standing subject the COP reflects the projected centre of gravity however repeatability and reliability of such analysis is lacking.

COP measurements were obtained from eight asymptomatic volunteers (mean age 32) with no history of back pain or previous spinal surgery. Each subject stood on a Zebris force plate platform for 30 seconds daily. 15 sets of data were acquired for each subject. For one subject, an additional 15 sets of data were collected on one day for comparison to the longitudinal data.

Intra- versus inter-subject reliability analysis revealed a Cronbach’s alpha value > 0.9 for the following COP movement parameters: distance travelled over 30 seconds, distance travelled in the first and last five seconds, and average speed. Comparison of the mean intra- versus inter-subject coefficients of variation revealed significant differences for all parameters (p< 0.004).

COP movement parameters are reliable in terms of intra-subject repeatability and can detect significant individual subject movement patterns. This suggests that COP movement patterns over time are idiosyncratic for each individual. While the repeatability of COP measurement has been established, the sensitivity to change with pathology and in response to treatment for spinal pathology remains to be evaluated.

Précis: Using full length x-rays and force plate technology, the purpose was first to investigate the relationship between the gravity line and spino-pelvic parameters on asymptomatic adult volunteers and then to analyse age related changes. Trunk inclination and pelvic parameters appears as the two key-factors of the GL location; with age the GL location regarding the heels does not change but trunk global inclination shifts forward, pelvic tilt increases, and the pelvis shifts toward the heels.

Introduction: Although work by several authors has placed emphasis on global balance in the setting of spinal deformity, the relationship of spino-pelvic parameters related to this concept remains poorly defined. Using the force plate device and radiographic measurement, this study aimed to define the relationship between these parameters and the location of the gravity line (GL) in asymptomatic adult population.

Materials and Methods: 75 asymptomatic adult volunteers were recruited and subdivided by age (18–40, 41–60, > 61). Full-length free-standing AP and lateral radiographs were obtained with simultaneous assessment of the force plate gravity line (GL) location. The latter was projected on each x-ray to compute distance between anatomical components and GL and correlate its location with radiological parameters. Age related changes were investigated using ANOVA with Bonfer-roni-Dunn Post-Hoc test.

Results: Radiographic measurements revealed strong correlations between trunk global inclination and distance from S1 to the GL (r=0.7), sacral slope and pelvic incidence (r=0.78), distance from the bi-femoral head axis to the GL and S1 to the GL (r=0.73), and sacral slope and lordosis (r=0.89). With advancing age, the GL location with respect to the heels does not change and a global spino-pelvic regulatory mechanism appears to maintain this posture: trunk global inclination shifts forward, pelvic tilt increases, and the pelvis shifts toward the heels, increasing its distance from the GL.

Discussion: his study demonstrates the importance of pelvic parameters and trunk inclination in the regulation of the GL location. The relationship between the gravity line, pelvic parameters, and overall spinal alignment may emerge as essential in the evaluation of spinal deformity. Further investigation in this field may lead to a formula of balance that can assist in optimal planning of corrective procedures for spinal deformity.

Précis: Gravity Line (GL) measurement by forceplate offers key information on standing balance. In this study x-ray measurements and GL offsets were calculated in two adult: volunteer controls, sagittal plane deformity patients. The deformity group revealed significant pelvic retroversion and posterior sacral displacement regarding GL and heels. However, GL-heel and GL-femoral head offsets were similar indicating that sagittal plane deformity may induce posterior pelvic translation and retroversion in order to maintain an inherent ideal/fixed GL-heel relationship.

Introduction: Sagittal spinal imbalance in the adult remains poorly understood and challenging. Limitations of radiographic analysis have lead researchers to apply forceplate technology to enhance the study of spinal balance through evaluation of the gravity line (GL). The aim of this study was to investigate differences between asymptomatic adults and patients with sagittal spinal deformities, with a hypothesis that imbalance would lead to changes in the GL – spinal relationship.

Material and Method: This prospective study included 44 asymptomatic subjects (mean 57yo) and 40 patients with sagittal deformities (mean 65yo, inclusion criteria: L1-S1 lordosis< 258, Pelvic Tilt> 208, C7 plumbline> 5 cm). Coronal plane deformities were excluded. Full-length free-standing sagittal radiographs were obtained with simultaneous acquisition of the GL and heel position (by forceplate). Spino-pelvic radiographic parameters were calculated and distances (offsets) from the GL analysed. Group differences were evaluated by independent sample t-tests.

Results: Groups did not differ in age, thoracic kyphosis, offsets from femoral heads to heels, femoral heads to GL, and GL to heels. As per inclusion criteria the sagittal deformity group had greater mean C7 plumbline (8cm vs 0cm), increased pelvic tilt (27° vs 13°) and loss of lordosis (46° vs 58°). The sagittal deformity group also had greater pelvic incidence (60° vs 51°), anterior trunk inclination (−3° vs −11°), S1 displacement toward the heels (distance decreased, 87 vs. 46mm). All differences p< 0.001.

Discussion: The sagittal spinal deformity group revealed marked differences; the sacrum has a more posterior position in relation to the GL and heels. However, the GL to femoral head offset was not markedly influenced. The additional finding of no change in the GL to heel offset and rather fixed GL-femoral head offset appears to indicate that sagittal spinal deformity induces a posterior sacral translation and pelvic retroversion in order to maintain a fixed GL-heel relationship.

Introduction: Several authors observed links between AIS and asymmetries as in function and anatomy, especially in the brain. Others described high frequency of AIS in patients suffering from craniofacial asymmetry (CFA). CFA involves asymmetry of Basicranium separating the face from the brain. Because of neurodevelopmental factors, CFA reflects brain growth. So, Posterior Basicranium (PB) asymmetry involves cerebellum asymmetry and spatial asymmetry of vestibular organs. In a previous study we highlighted that CFA was associated with functional anomalies: difficulty of fixation caused by ocular torsion, off balance caused by vestibular dysfunction, postural disorders.

Purpose: To explore AIS on different levels: PB, Eyes and Vestibular System.

Patients:

Control group (CG):32 subjects, 26W. & 6M., fr. 8 to 51.

Methods: We used MRI (EXCITE G.E.) 1.5T, head coil, Volumic T2-weighted sequence.

Step1: 3D Basicranium measurements in both groups with Brainvisa processing: (http://brainvisa.info/)

Discussion: Normal subjects revealed weak asymmetry and dorsoventral rotation of P.B & cerebellum

AIS showed a pathognomic increase of these Human traits. Inside AIS subgroups, TL & G3 revealed highest levels of asymmetry and rotation.

We will discuss, thanks to AIS homozygosis twins in mirror, genetic origins for these specific P.B. & Cerebellum asymmetries.

Modelling of semi-circular canals revealed significative malformations in AIS compared to normal group. Again, T.L. and G3 revealed highest scores of canals anomalies. We highlighted a specific malformation in AIS: abnormal connexion between lateral & posterior canal.

We will demonstrate, thanks to same AIS twins, genetic origins of this malformation and propose a genetic hypothesis to link the different results.

Conclusion: These specific anomalies could be considered as preventive factors of AIS. Work supported by Cotrel Fondation.

Nachemson [2] drawing upon the theses of Sahlstrand [3] and Lidström [4] articulated the view there are more girls than boys with progressive AIS for the following reason. The maturation of postural mechanisms in the nervous system is complete about the same time in boys and girls. Girls enter their skeletal adolescent growth spurt with immature postural mechanisms – so if they have a predisposition to develop a scoliosis curve, the spine deforms. In contrast, boys enter their adolescent growth spurt with mature postural mechanisms so they are protected from developing a scoliosis curve. We term Nachemson’s concept the neuro-osseous timing of maturation (NOTOM) hypothesis [1,5] The earlier sexual and skeletal maturation of girls may have an evolutionary basis through natural selection. Curve progression in AIS is associated with acceleration of the adolescent growth spurt [6]. Postural sway involves proprioceptive, vestibular and visual input to the central nervous system. In normal children there is a significant reduction in postural sway amplitude between six to nine years and 10–14 years [7,8]. In 1071 normal children aged 6–14 years postural sway is more stable in girls from 6–9 years and over 10 years there is no sex effect [9]; all these findings fit the Nachemson concept. But in view of a subsequent report on 64 normal children aged 3–17 years showing the change with age is limited to boys [10] the age and sex effect of postural sway in healthy children needs further evaluation. In AIS children stabilometry findings are conflicting and observed greater postural sway may be secondary to the curve. In the siblings of scoliotics Lidström et al [11] concluded that postural aberration is a factor in the aetiology of AIS.

Conclusion: The NOTOM hypothesis suggests a treatment to prevent progression of late-juvenile idiopathic scoliosis, early-AIS, and some secondary scolioses. It is based on delaying the onset of the adolescent growth spurt and puberty as used therapeutically in children with idiopathic precocious puberty (IPP)[12]. The proposal is to administer a gonadorelin analogue which in the pituitary down-regulates receptors to hypothalamic gonadotropin-releasing hormone (GnRH) causing a fall in both luteinizing hormone (LH) and follicle-stimulating stimulating hormone (FSH); in turn this causes a fall in oestrogens and androgens and thereby delays or stops menarche and slows bone growth – as in girls and boys with IPP [13]. Expert paediatric opinion is supportive. King [14] has suggested the use of a gonadorelin analogue (Lupron) to delay the onset of the adolescent growth spurt in progressive AIS.

The possibility that AIS aetiology involves undetected neuromuscular dysfunction is considered likely by several workers [1,2]. Yet in the extensive neuroscience research of idiopathic scoliosis certain neurodevelopmental concepts have been neglected. These include [3]:

a CNS body schema (“body in the brain”) for posture and movement control generated during development and growth by establishing a long-lasting memory, and

During normal development the CNS has to adapt to the rapidly growing skeleton of adolescence, and in AIS to developing spinal asymmetry from whatever cause. Examination of publications relating to the CNS body schema, parietal lobe and temporo-parietal junction [4,5] led us to a new concept: namely, that a delay in maturation of the CNS body schema during adolescence with an early AIS deformity at a time of rapid spinal growth results in the CNS attempting to balance the deformity in a trunk that is larger than the information on personal space (self) already established in the brain by that time of development. It is postulated that this CNS maturational delay allows scoliosis curve progression to occur – unless the delay is temporary when curve progression would cease. The maturational delay may be primary in the brain or secondary to impaired sensory input from end-organs [6], nerve fibre tracts [2,7,8] or central processing [9,10]. The motor component of the concept could be evaluated using transcranial magnetic stimulation [11].

Conclusion: Any maturational delay of the CNS body schema could impair postural mechanisms in girls and boys with or without early AIS deformity. The “body in the brain” concept adds a particular CNS mechanism (maturational delay) to the neuro-osseous timing of maturation (NOTOM) hypothesis for the pathogenesis of AIS [12,13]. The NOTOM hypothesis states that there are more girls than boys with progressive AIS because of different developmental timing of skeletal maturation and postural maturation between the sexes in adolescence [12,13].

The aetiology of idiopathic scoliosis, despite of long-lasting efforts to disclose it, remains unknown.

The purpose of the study was to evaluate the spine development after pinealectomy or cortical sensory motor area damage in the growing rats.

Method: The authors operated 69 Wistar albino rats (aged three to four weeks) in antraperitoneal anaesthesia. In the first group (22 rats) pinealectomy – PIN was performed, in the second one (25) the sensory motor cortical area 2x1x1 mm bellow the coronal suture was removed – SMCA. The sham operation consisted of craniotomy – CRA (11 rats) and craniotomy with durotomy – CRDU (11 rats). All surgeries were performed from the left side. Radiography was made three months after surgery. Scoliosis, C2-T7 lordosis, T7-S1 kyphosis were measured. Results have been processed by software Statistica 7.1. StatSoft, Inc. (2005). We used ANOVA test for evaluation of potential difference between groups, in the case of approving the difference between groups, we tested difference between each two groups by two-sample t-test. Those tests were realised on 0,05 significant level.

Results: In the PIN group scoliosis 9–14 degrees (mean value 10,8) developed in five animals, in SMCA group scoliosis 10 – 24 degrees (mean value 15,9) was observed in eight animals.

These statistically significant differences were found: higher surgery weight in PIN, longer surgery time in PIN and SMCA, lower lordosis in PIN and higher in CRDU, differences of all groups in kyphosis and in an end weight.

Conclusion: Our results indicate the importance of cortical area damage, together with craniotomy and durotomy in the development of growing rat spine. We cannot exclude the influence of peri-operative bleeding, brain hypoxia or metabolic effect of anaesthetics.

These damages could cause a disorder of balance between smaller inhibitory and greater facilitating area of CNS, controlling the muscular tone and resulting in the development of lordosis and scoliosis due to muscle imbalance.

While previous studies have highlighted possible aetiological factors for adolescent idiopathic scoliosis (AIS), research employing gait measurements have demonstrated asymmetries in the ground reaction forces, suggesting a relationship between these asymmetries, neurological dysfunction and spinal deformity. Furthermore, investigations have indicated that the kinematic differences in various body segments may be a major contributing factor. This investigation, which formed part of a wider comprehensive study, was aimed at identifying asymmetries in lower limb kinematics and pelvic and back movements during level walking in scoliotic subjects that could be related to the spinal deformity. Additionally, the study examined the time domain parameters of the various components of ground reaction force together with the centre of pressure (CoP) pattern, assessed during level walking, which could be related to the spinal deformity. Although previous studies indicate that force platforms provide good estimation of the static balance of individuals, there remains a paucity of information on dynamic balance during walking. In addition, while research has documented the use of CoP and net joint moments in gait assessment and have assessed centre of mass (CoM)–CoP distance relationships in clinical conditions, there is little information relating to the moments about CoM. Hence, one of the objectives of the present study was to assess and establish the asymmetry in the CoP pattern and moments about CoM during level walking and its relationship to spinal deformity.

The investigation employed a six camera movement analysis system and a strain gauge force platform in order to estimate time domain kinetic parameters and other kinematic parameters in the lower extremities, pelvis and back. 16 patients with varying degrees of deformity, scheduled for surgery within a week took part in the study. The data for the right and left foot was collected from separate trials of normal walking. CoP was then estimated using the force and moment components from the force platform.

Results indicate differences across the subjects depending on the laterality of the major curve. There is an evidence of a relationship between the medio-lateral direction CoP and the laterality of both the main and compensation curves. This is not evident in the anterior-posterior direction. Similar results were recorded for moments about CoM. Subjects with a higher left compensation curve had greater deviation to the left. Furthermore, the results show that the variables identified in this study can be applied to initial screening and surgical evaluation of spinal deformities such as scoliosis. Further studies are being undertaken to validate these findings.

Introduction: Classification systems in relation to scoliosis have been a hallmark for the clinician in the development of therapeutic options. The triple curve pattern with three distinct lateral curvatures of approximately equal severity has been recognised as distinct and, potentially, unique in its presentation. From a large population of families with FIS, a subpopulation of families with a triple curve pattern was evaluated in order to determine if this curve pattern is distinct on a genetic level.

Methods: With IRB approval, a sample of families with FIS (202 families, 1198 individuals) were recruited and underwent a genomic screen. The results were analysed using a model independent linkage analysis (SIBPAL). A subgroup of FIS families with at least one member having a triple curve was identified (six families, 32 individuals). After initial linkage analysis, the group underwent further fine mapping analysis utilising a battery of SNPs.

Results: Analysis of the data from the genomic screen on the triple curve subgroup revealed significant areas on chromosome 10 when analysed qualitatively and quantitatively in either a single-point or multipoint fashion.

Conclusion: The utilization of clinical data to discern potential relevance of specific genetic loci in the aetiology of FIS has resulted in an area on chromosome 10 that is significant (p < 0.01). The relatively small population of families within this subgroup coupled with the strength of the data suggests a unique genetic etiological factor associated with the formation of a triple curve in FIS.

Introduction: Adolescent idiopathic scoliosis (IS) is the most common spine deformity arising during childhood, but the aetiology of IS remains unknown. A large proportion (75%) of structural scoliosis is clinically classified as idiopathic. Idiopathic scoliosis often appears in several members of the same family, this strongly suggesting a genetic transmission. Clinical studies indicate that approximately 1:4 of the total scoliosis cases and 1:3 of idiopathic scoliosis cases are familial. Also studies on twins showing that concordance of monozygotic twins is greater than that of dizygotic twins suggest a genetic basis for the idiopathic scoliosis. A series of candidate genes, including FBN1, COL1A1, COL1A2, COL2A1 and elastin genes, have already been examined by linkage studies, with negative results, and, at present, the particular mode of inheritance of the idiopathic scoliosis still remains unclear. There are conflicting data in the existing literature. Some reports show that the disorder has many of the characteristics of a complex trait, indicating the presence of a multifactorial inheritance pattern, while other studies indicate a major autosomal dominant gene effect. Even more, not all the linkage studies, which demonstrate that the inheritance pattern of idiopathic scoliosis is based on a major autosomal dominant gene effect, did identify a unique locus responsible for idiopathic scoliosis. A linkage with idiopathic scoliosis has been found at locus 17p11 in a three generation Italian family and at locus 19p13.3 in a Chinese family. Therefore, it is possible that idiopathic scoliosis is caused by alterations in different genes.

Study Design: This study aimed at investigating the loci responsible for susceptibility to idiopathic scoliosis in all the population and not only in single families. For this reason, we chose to perform an association study on parent-offspring trios. A genetic study and statistical linkage analysis of a population of 81 trios, each consisting of a daughter/son affected by idiopathic scoliosis (IS) and both parents.

Objectives: The objective of this study was to assess a linkage disequilibrium between the matrilin-1 (MATN1) gene and the idiopathic scoliosis (IS).

Summary of Background Data: In a previous study (Giampietro et al., 1999), a number of genes, associated with spine musculoskeletal deformity phenotypes in mouse and in synteny between mouse and man, were identified as candidate genes for IS. Among these genes, MATN1, which carries a polymorphic micro-satellite marker within its sequence, was selected for a linkage analysis. MATN1 is localised at 1p35 and is mainly expressed in cartilage.

Methods: In all trios components, the region of MATN1 gene containing the microsatellite marker was amplified by a polymerase chain reaction. The amplicons were analysed by a DNA sequencer-genotyper. The statistical analysis was performed using the extended transmission/disequilibrium test.

Results: Three microsatellite polymorphisms, respectively consisting of 103 bp, 101 bp and 99 bp, were identified. ETDT evidenced a significant preferential transmission for the 103 bp allele (2 = 5.058, df=1, P=0.024).

Main Conclusions: The results suggest that the familial idiopathic scoliosis is linked to the MATN1 gene.

Introduction: Adolescent idiopathic scoliosis (AIS) is described as a sex-influenced autosomal dominantly inherited disorder with females more often affected than males, and operative ratio of 7F:1M (Child et al. 1999). Two AIS loci have been reported on chromosome 17p11 (Salehi et al. 2002) and chromosome 19p13.3 (Chan et al. 2002) in the Italian and Chinese populations, respectively. Three other susceptibility AIS loci on chromosome 6q, distal 10q and 18q (Wise et al. 2000), and more recently primary candidate regions on chromosomes 6, 9, 16, and 17 (Miller et al, 2005) have also been reported.

Purpose: o perform a genome scan for suitable UK multiplex families and identify new genetic loci for AIS.

Method: NA samples from 208 subjects (134 affected, 17 reduced penetrance members and 79 normal) from 25 multi-generation British families with confirmed diagnosis of AIS were selected from our AIS family database, and genotyped for 410 polymorphic markers from the entire genome, spaced at 10 cM intervals. Genotypic data were exported into Cyrillic to construct the most likely inherited haplotypes for each chromosome and in each family. Two–point LOD scores were calculated using MLINK initially for the entire genotypic data, and again for the affected meioses only, followed by GENEHUNTER for multipoint linkage analysis for each family.

Results: Overall, 170 560 genotypes were obtained and analysed. DNA samples from 250 subjects from the 25 families are currently available for further genotyping and saturation mapping. Our AIS families show absence of linkage to the X chromosome as well as previously reported AIS loci, except for chromosome 9q and 17q as reported by Miller et al. (2005). Preliminary inspection of inherited haplotypes indicates that a number of these families may be segregating with several new AIS loci with LOD scores ranging from 1.0 – 3.63 for various DNA markers on 15 different chromosomes. Linkage evaluation and comprehensive saturation mapping of the two loci with the highest LOD scores of 3.63 and 4.08 for chromosomes 9q and 17q respectively were conducted and these regions were successfully refined. Candidate genes are currently being screened.

Conclusion: Preliminary evidence already indicates genetic heterogeneity of AIS. Candidate genes from the highest LOD score regions are at present being screened.

Introduction: Familial idiopathic scoliosis (FIS) is a complex genetic disorder potentially resulting from multiple genetic interactions and variants. A previous genome wide screen in a large population of families with FIS followed by fine mapping utilizing STRP’s identified and narrowed critical regions on chromosomes 9 and 16. A high density SNP map was then designed across these regions. This array was then assayed within the same population in an effort to link and/or associate specific genetic intervals or candidate genes with the expressed phenotype.

Methods: A sample of families with IS (202 families, 1198 individuals) was recruited with IRB approval and underwent a genomic screen. Results were analysed by model-independent linkage analysis (SIBPAL). Following initial analyses, families were then stratified according to mode of inheritance. 101 families (550 individuals) represented an autosomal dominant mode of heritability and underwent fine mapping in the candidate regions.

Custom SNP pools were designed for the candidate regions at a density of 1 SNP/58Kb. DNA from 550 individuals (AD group) were genotyped using the Illumina platform. A total of 1536 SNP markers were attempted, of which 1324 were released; 519 SNPs were genotyped on 9q32-24 and 805 SNPs genotyped on 16p12-q22. The map was generated using NCBI dbSNP chromosome report on Build 34. Overall missing rate was 0.06%; the overall duplicate error rate was 0.05%.

FIS was analysed both as a qualitative trait with an arbitrary threshold, and as a quantitative trait, or the degree of lateral curvature. Model independent sib-pair linkage analysis was performed on the subsets (SIBPAL, S. A. G. E. v4.5).

Results:

Chromosome 9: Multipoint model-independent qualitative analysis (threshold at ten degrees) did not result in any p values of < 0.05. When the threshold was set at 30 degrees, several regions with p values of < 0.005 were observed. One region spanned 10 Mb, and coincides with the region found to be most suggestive of linkage at the 0.05 level for the quantitative analysis which was 6 Mb in length.

Discussion: The current work has significance in the stepwise confirmation and narrowing of genomic regions which are potentially meaningful in the aetiology of FIS. Stratification of the initial sample into subgroups, initially by heritability and then by threshold of disease resulted in heightened significance at specific markers demonstrating the heterogeneity of this disorder. Ultimately, the independent association of genetic loci and this disorder will enhance the ability to elucidate prognosis, counsel patients, and guide therapeutic plans.

Purpose: Adolescent idiopathic scoliosis (AIS) is know to occur in families and research has shown that in populations or predominantly Northern European origin, 97% of AIS patients are related to families with AIS. It affects 1–2% of the population and results in deformities treated by bracing and surgery. Brace prescription is empirical and surgery is reserved for late cases and brace failures. Identifying the genetic markers for AIS would allow creation of a diagnostic gene-based test that may also have prognostic value for differentiating progressive and non-progressive curves.

Methods: A 21 million name data base of the original European pioneers in Utah was assembled including 3 million descendents and 18 million ancestors. 500 DNA samples from affected and first degree unaffected relatives were collected and genotypes determined with capillary electrophoresis using 763 autosomal markers and gene chip scanning for 116 000 SNPs. Disease haplotypes were also scanned with a 500K SNP chip to further narrow the position of each loci.

Results: Two markers were identified with LOD scores of 7.0 and 7.3. p-values from SNP scanning were highly significant. More detailed descriptions of these genotypes will be presented.

Conclusion: Two genetic markers were identified, one of which was present in 95% of patients with AIS greater than 40°. In our population, no one with AIS less than 40° had these markers. A genotype test for AIS may be possible that would offer both diagnostic and prognostic value. Further characterization of the genes and their mutations could give information concerning the molecular pathway that lead to disease expression.

Idiopathic scoliosis has been studied through centuries, but problems of its aetiology and pathogenesis up till now are the subjects of considerable discussion. Pathogenetic mechanism of the spine deformity development in idiopathic scoliosis (IS) was established on the basis of in-depth morphological and biochemical investigations of structural components of the spine in patients with IS (surgical material) (Zaidman A.M., et al. 2001). It was shown that IS develops on the basis of disturbance of proteoglycans (PG) synthesis and formation in vertebral growth plates. Decrease of chondroitin sulphate component of PG and increase of keratan sulphate one, as well as decrease in degree of sulphating of glycosaminoglycan (GAG) chains and increase of non-acetilated sugars – all this evidences for conformational changes in proteoglycans. The found keratan sulphate-related fraction is likely a marker of genetic changes in PGs in idiopathic scoliosis. Structural changes in PGs in combination with reduce of quantity of diffuse molecules which perform trophic and informational function, and disorders of receptor function of chondroblast membranes (ultra structural and histochemical findings) are the factors of disorders in regulation mechanisms of vertebral growth plate cells and matrix differentiation and reproduction.

Long-term studies (Zaidman A.M., et al., 1999–2003) demonstrated a major-gene effect in Idiopathic Scoliosis. The next stage was major gene localization by the method for candidate gene testing. The aggrecan gene with known polymorphism of the number of tandem repeats in exon G3 was considered to be one of these candidate genes. Various alleles of this gene provide attachment of different number of chondroitin sulfate chains to a proteoglycan core protein, thereby changing functional properties of cartilage. The aggrecan gene AGC1 coding a core protein of aggrecan molecule has been localised to region 15q2b. In anald families nine alleles of aggrecan gene have been identified, among them three alleles with tandem repeats numbers of 25, 26, and 27 prevailed. We did not reveal preferable transmission of any of these alleles to the proband The absence of reliable association of IS with polymorphism of exon G3 can not be interpreted as a non-linkage of the whole aggrecan gene to IS development determination.

As the linkage of other proteoglycans to IS development has not been excluded, we perform the RT-PCR and immunoblot analyses of the expression of main PG genes and their protein products in cultivated chondroblasts isolated from vertebral growth plates in 15 patients with III–IV grade IS (surgical material). The study has shown that aggrecan gene expression is significantly decreased in cultivated chondroblasts from patients with IS, what correlates with a decrease of synthesed protein product, both in cells (chondrocytes) isolated from IS patients and in cultural media. The presence of keratan sulphate-related fraction and keratan sulphate increase are associated with luminicene increase. In present we perform a sequencing of aggrecan genome.

Since the first pathography of Idiopathic Scoliosis (IS) and Scheuermann’s disease (SD) clinicians consider these two pathologies as separate nosological entities. The reason for this is different clinical implications of diseases. SD is known to be more common in boys, while IS is a sad privilege of girls. Kyphotic spinal deformity is typical for patients with Scheuermann’s disease while scoliotic one for patients with idiopathic scoliosis. Schmorl’s nodes are found more frequently in SD. Both deformities are attributed to the growth asymmetry, anterior growth plates are affected in SD and lateral ones – in IS. Despite different clinical presentations, these two nosologies have the same pathogenetic mechanism and semiology.

To our regret, there are no reports on comparative morphological and biochemical investigations of SD and IS. Long-term studies have given rise to the question of a single nature of scoliotic and kyphotic spine deformities.

Material and methods: Clinical and genetic examination with segregational analysis of pedigrees was performed in 350 families with IS and in 95 families with SD. Structural components of the spine obtained from IS and SD patients operated in our Institute were studied with morphological and biochemical techniques.

The potency for synthesis and structural organization of chondroblasts isolated from vertebral body growth plates of patients with IS and SD were subjects of morphological, biochemical, and ultrastructural analyses. Qualitative and quantitative composition of growth plates was investigated in culture mediums.

Results: Clinical and genetic examination of families with IS and SD have shown that both pathologies are inherited both from maternal and paternal lines. Families presented combinations of these pathologies. Segregational analysis of IS and SD pedigrees has revealed major gene dependence of both pathologies inherited by autosomal-dominant type with incomplete penetrancy genotypes according to gender and age. In experimental animal model of genetically dependent spine deformity there were cubs either with scoliosis or with kyphosis in one litter. The target organ for pathologies discussed is growth plate and secondary disorders of vertebral body and disc structure.

Morpho-histochemical study of the spine structural elements has revealed the same changes in patients with IS and patients with SD:

Disturbance of structural and chondral organization of cells and matrix in vertebral body growth plate.

Our knowledge of the incidence of scoliosis and scoliosis surgery is based on a few small scale studies. The National Health Service (NHS) in the United Kingdom has long collected data on hospital based activity. We have used a five year English database (1998–2002) of hospital admission statistics to study age-adjusted admission rates for scoliosis (code M41 in the International Classification of Diseases, 10th revision) and for two scoliosis surgery codes (V41 ‘instrumental correction of deformity of spine’ and V42 ‘other correction of deformity of spine’ (the latter includes ‘anterolateral release of spine for correction of deformity’).

Results: Three thousand, seven hundred and eighty three patients (2533 females and 1240 males) aged 5–29 years had diagnosis M41 recorded over the five year sample period. Most of the patients were teenagers. 971 (males and females) of these had operation V41 and 1212 had V42, it is likely that the vast majority of these cases had idiopathic scoliosis. We made regional maps based on age-adjusted admission rates/100000 population. Admission rates varied from 5.75/100000 (95% confidence intervals x to y) in London to 2.8/100000 (x to y) in the Yorkshire-Humberside region.

Interpretation: There was wide geographical variation in admission rates. We considered 5 hypotheses:

Social deprivation – we were able to study this, and admission rates appeared independent of social deprivation.

Conclusion: There is wide variation in recorded rates of diagnosis and surgical treatment without obvious explanation. It might be possible to study clinical case notes, identified from the statistical database, to check whether variation is simply attributable to unreliability of coding. To determine whether there may be a genetic explanation for the geographical variation found by us, the possibility could be explored of comparing the scoliosis maps with other maps of genetic profiles of the English population.

Recent literature has reported multiple critical regions identified through linkage analyses to be potentially relevant in relationship to the aetiology of FIS. This is supportive of the concept that FIS is a complex genetic disorder resulting from multiple genetic interactions and variants. While these areas harbour multiple genes, the work to date has been crucial to our ability to focus and hopefully eliminate massive areas on the genome that are irrelevant to this disorder. As one reviews these genes, however, one should develop a potential algorithm for prioritization of candidate genes. Additionally, one should delve into potential biological mechanisms in relationship to the creation of a spinal deformity. If you were a gene causing scoliosis, what would you look like and how would you function?

One approach to prioritization of candidate genes may be based on the virtue of their direct potential as a biological basis for the deformity, such as genes that encode for a protein of known function, the function of homologous proteins, and the tissue expression pattern. Within the localised region of chromosome 9, one such gene is COL5A1, a precursor for collagen type V alpha chains, a fibrillar forming collagen ubiquitously distributed within the connective tissues. A second group of genes may be those genes encoding regulatory proteins of the extracellular matrix.

Transmembrane 4 superfamily, member 6 (TM4SF6) localised on the critical region on Xq22 is believed to span the cellular membrane with a role in cellular adhesion within the matrix. A third group of genes may maintain a temporal and/or spatial pattern of expression that may relate to the building of the axial skeleton itself. The Iriquois genes isolated on chromosome 5 play multiple roles in embryonic development including anterior/posterior and dorsal/ventral patterning of the central nervous system. Lastly, genes that do not have an intuitive relationship to scoliosis, but are localised within areas of strong linkage, will need to undergo analysis. Multiple examples exist within the reported critical regions within the literature to date.

Another approach to the review of candidate genes within the regions is to think of known genetic disorders in which, 1) scoliosis is recognised as an element of the phenotype, and, 2) the gene and the biological mechanism of the disorder is well known. Immediate potential examples that come to mind are that of known collagen disorders such as osteogenesis imperfecta. The assumption that scoliosis is solely a result of mechanical load imposed upon abnormal connective tissue may be more elementary than what is truly occurring. Another example may be that of neurofibromatosis (gene – NF1). While this particular gene is localised near one of the identified regions, unfortunately, the biological function of the gene in relationship to phenotypic findings is still unknown.

In conclusion, genetic research related to FIS to date has driven us to unbelievable expectations within a relatively short period of time. Further understanding of this complex disease will best be accomplished with thoughtful experimental, orderly design ultimately to have an impact in the therapeutic treatment of this disorder.

Introduction: Patient questionnaires permit a direct measure of the value of care as perceived by the recipient. The Scoliosis Research Society outcomes questionnaire (SRS-22) has been validated as a tool for self-assessment. We investigated the correlation between SRS-22 and a detailed radiological outcome two years following anterior correction of Thoraco-Lumbar Adolescent Idiopathic Scoliosis (TL-AIS).

Methods: The SRS-22 questionnaire was completed by 30 patients two years following anterior correction of TL-AIS. Pre-operative, post-operative and two year follow-up radiographs of all 30 patients were assessed. The following parameters were measured at each time point:

Primary Cobb angle,

The percentage improvements for each were noted. Correlation was sought between Total SRS score, each of the five individual domains and various radiographic parameters listed above by quantifying Pearson’s Correlation Coefficient (r).

Results: Percentage improvement in primary Cobb angle (r = 0.052), secondary Cobb angle (r = 0.165) and AVT of the primary curve (r = −0.353) showed little or no correlation with the SRS-22 total score or any of its five domains. Significant inverse correlation was found between the UIV tilt angle at two years and the SRS-22 (r = −0.516). Lateral radiographs however showed little or no correlation between thoracic kyphosis (r = 0.043) and SRS-22.

Conclusion: The SRS-22 outcomes questionnaire does not correlate with most of the radiographic parameters commonly used by clinicians to assess patient outcome.

An automated system has been developed to measure three-dimensional back shape in scoliosis patients using structured light. The low-cost system uses a digital camera to acquire a photograph of a patient with coloured markers on palpated bony landmarks, illuminated by a pattern of horizontal lines. A user-friendly operator interface controls the lighting and camera and leads the operator through the analysis. The system presents clinical information about the shape of the patient’s deformity on screen and as a printed report. All patient data (both photographs and clinical results) are stored in an integral database. The database can be interrogated to allow successive measurements to be plotted for monitoring the deformity.

The system is non-invasive, requiring only a digital photograph to be taken of the patient’s back. Identification of the bony landmarks allows all clinical data to be related to body axes. This reduces the effects of variability in patient stance. Measurement of a patient, including undressing, landmark marking and dressing, can be carried out in approximately 10 minutes. The clinical results presented are based on the old ISIS report. This includes:

transverse sections at 19 levels from vertebra prominens to sacrum.

Additionally, a three-dimensional wire-frame plot, a coloured contour plot and a pair of bilateral asymmetry plots give visual impressions of any deformity in the measured back.

Précis: A recently developed Classification of adult scoliosis was utilised to study surgical treatment in 339 patients. At 12 month follow up after surgery for thoracolumbar/lumbar scoliosis greatest improvement in outcome scores were noted in the following patients: lost lumbar lordosis, treatment with osteotomies, fusion to the sacrum for marked sagittal imbalance. Complication rates were greatest for: fusion to the sacrum, sagittal imbalance greater than 4cm.

Introduction: A recently proposed radiographic Classification of adult scoliosis offers a useful system with high clinical impact and reliability. Continued work is required to apply this system in the development of treatment guidelines. The purpose of this study was to anal surgical treatment outcomes, and complications, by Classification subtype at 12 months post-operative follow up.

Material and Method: This study included 339 patients: Type IV (thoracolumbar major) and Type V (lumbar major) adult scoliosis (Spinal Deformity Study Group). All patients had complete full-length spine radiographs and outcomes questionnaires (SRS, ODI and SF-12). An analysis of classification subtypes (modifiers) included outcome scores by surgical treatment. The latter included approach (anterior, posterior, both), use of osteotomies, and extension to the sacrum (or not).

Results: Lordosis modifier was strongly correlated with baseline disability and post-operative improvement. Type C (loss of lordosis) patients had the lowest baseline outcome but also greatest improvement with surgery (p< 0.05). Subluxation modifier had impact on preoperative but not on postoperative outcomes measures. Marked sagittal balance had the worst outcomes of all groups if fusion fell short of the sacrum. Patients with osteotomies saw greater improvement than those without (p< 0.05). Anterior, posterior or combined procedures showed no significant difference in outcomes. Peri- and post-operative complications did not vary by lordosis modifier, subluxation modifier but were elevated for fusion to the sacrum (p< 0.05).

Conclusion: At 12 month follow up for surgical treatment of adult thoracolumbar/lumbar scoliosis greatest improvement in outcome scores were noted in the following patients: lost lumbar lordosis, treatment with osteotomies, fusion to the sacrum for marked sagittal imbalance. Complication rates were greatest for: fusion to the sacrum, sagittal imbalance greater than 4cm. Further longitudinal follow up will permit validation of optimal treatment by Classification type of adult spinal deformity and refine patient and surgeon expectations of operative care.

Précis: A multi-centre prospective effort focused on analysis of a previously reported Classification of adult scoliosis. 809 thoracolumbar/lumbar deformities were studied. Radiographic analysis (deformity apex, lumbar lordosis, intervertebral subluxation), outcomes measures (ODI, SRS instruments) and surgical rates were examined. The Classification into Types, based on deformity apex location, and addition of modifiers (lordosis, subluxation) established clinically significant groups (disability, pain). In addition to high clinical impact, the Classification was also able to predict surgical rates.

Introduction: A recently proposed radiographic classification of adult scoliosis offers a reliable method of categorizing patients. Continued work on this classification is expected to develop treatment guidelines. This investigation anald treatment patterns of a large patient population of thoracolumbar and lumbar adult scoliosis, emphasizing surgical rates and approaches by classification subtypes.

Methods: This investigation anald 809 Type IV (thoracolumbar major) and Type V (lumbar major) curves from the Spinal Deformity Study Group database. Enrolled patients had complete SRS, ODI and SF-12 outcomes questionnaires and free standing full-length spine radiographs. Analysis compared non-operative versus surgical treatment (no imposed protocol) with surgical treatment assessed by approach (anterior, posterior, both), +/− osteotomies.

Results: Of 809 patients, 348 were treated surgically (43%) and classified as lordosis type A (n=422), B (n=313), C (n=74). Surgical rates were greater for B vs. A (51% vs. 37%, p< 0.05)), trend for A vs. C (46%). Subluxation modifier scores: 0 (n=360), + (n=159), ++ (n=290). Surgical rates were greater for ++ vs. 0 (52% vs. 36 %, p< 0.05), trend vs. + (42 %). Greater sagittal imbalance was more likely to receive surgical treatment. Loss of lumbar lordosis (modifier B, C) was associated with increased osteotomy rates and posterior or circumferential treatment versus anterior only procedures (most common in modifier A). Greater subluxation (modifier ++) was associated with more circumferential surgery. Greater sagittal imbalance was associated with higher rate of posterior only surgery.

Discussion: In this analysis, greater lordosis or subluxation modifier score was associated with higher surgical rates. Loss of lordosis and greater subluxation grade was associated with higher rates of circumferential surgery than lordotic spines or those without significant subluxation. This information suggests the ability of this classification system to predict treatment. Longitudinal follow up will permit validation of optimal treatment by classification of adult spinal deformity.

Background: Surgical treatment of spinal deformities is complex and is performed by a limited number of spine surgeons. To obtain adequate radiological and clinical correction, a large amount of clinical experience is required when planning corrective surgery because of the enormous amount of patient related variables, and the many surgical techniques (e.g. rod rotation vs translation, pedicle screws vs hooks, anterior vs posterior).

The widely used classification systems (King and Lenke) are useful for documentation of the deformities. Unfortunately explicit guidelines for surgery are not clear. A multi-centre database with pre and postoperative patient data including photographic images and x-rays will be very useful in decision making. It will allow surgeons to find similar cases in the database that will help them in their decision making for surgical planning and execution. Furthermore it will provide extensive data to perform outcome studies, and to develop general treatment guidelines. Surgery for spinal deformities will become more evidence based and less dependent on the individual surgeons judgement.

Methods: A modern web-based database system, Scolisoft was developed for documenting patient data and curve characteristics. The system contains patient data (demographics etc), radiological data (AP, Lat, bending films), classification of curve patterns according to the often-used classification systems and information about the surgical procedure. It includes pre and postoperative radiological data and clinical photographs.

The patient data can also be stored and printed as a PDF-file, so that it can be used as a patient chart and for patient information purposes.

Scolisoft allows the user to select patients based on all the individual characteristics, e.g. curve classification. For pre-operative planning of a specific deformity, a cohort of patients with the same deformity (patient demographics, curve pattern, bending films etc) can be selected and the postoperative results viewed.

With the same selection tool, cohorts of patients can be selected for outcome studies.

Furthermore Scolisoft provides the possibility of discussing difficult cases with other spine surgeons using the system.

Finally, complications are registered according to the existing Scoliosis Research Society complication registry system.

Experiences: Data of more than 200 patients have been entered into the former PC application system. The current web based system has 60 cases that have been entered during its trial phase. Most cases have been adolescent or adult idiopathic scoliosis. Forty two surgeons have used the software and eight surgeons have participated in entering cases. The web-based version has shown to be very user friendly. Submitting the radiological and clinical images is easy (but takes some time). All data input is possible by a simple click of the mouse. Therefore it is relatively easy to learn.

The system already has the possibility for documenting other spine pathology such as sagittal plane deformities, fractures and spondylolisthesis.

Conclusion: Scolisoft is a powerful, user-friendly web-based registry for spinal deformities. It is a very useful tool in planning spinal deformity surgery and research. In this time of evidence-based medicine, it is time to take the planning of scoliosis surgery out of the realm of myth, and this database is a strong step in that direction.

Introduction: In situ contouring is meant to give the shape of the spine to the rod and then the shape of the rod to the spine. Thus, it is used in order to set up the instrumentation as well as to reduce the spinal deformity. This technique was born in 1993, when we presented our first scoliosis correction results (CT scan study of vertebral derotation) with the rod rotation technique during the French SRS (GES). Our great disappointment with the rod rotation technique forced us to try to find a different correction method.

Scoliosis is the consequence of vertebral rotation. Each vertebra turns about a different axis which results into a global torsion of the spine. This torsion will yield characteristic modifications. On the frontal x-ray view one can notice the maximum projection of the deformity, usually estimated by means of the Cobb angle, whereas on the sagittal x-ray view a flat back will be observed. Indeed, scoliosis flattens sagittal physiological curvatures. Hyperkyphosis may occur only between two scoliotic curves (two adjacent flat back segments) or in case of vertebral rotation higher than 90° when the sagittal projection corresponds to frontal structures. In this last case, the maximum deformity is projected on the sagittal view. The vertebral rotation will also pull on the ribs, thus creating the rib hump.

Classical Surgical Techniques: Nowadays there are several classical correction techniques for scoliosis treatment.

Over the last decades, Harrington developed the distraction-compression technique, then Eduardo Luque proposed the spinal translation technique, and latter on Cotrel and Dubousset developed the rod rotation method that revolutionised spine surgery.

By pulling on the concave side of the spine, the distraction-compression technique is intended to reduce the deformity shaft while dragging along the apex in a pure translation movement. The distraction is applied mainly onto the flexible segments, far from the apex. Therefore, the apex will hardly modify its relative position with regard to the other vertebrae. Besides, there is a high risk of spinal cord stretching on the concave side at the apex level.

Furthermore, this technique is often associated with a high rate of post-operative flat back and requires postoperative cast and brace wear as the fixation remains fragile. Last but not least, the traction technique does not solve the rotation problem. On the contrary, traction increases the torsion forces and leads to higher rotation constraints.

The spinal translation used to be performed by means of metallic wires passing under the lamina that were tightened around the rod. This technique of scoliosis correction was based on a totally different correction mechanism with regard to Harrington’s one. Indeed, medialisation of the apex results into a spontaneous increase of the intervertebral gap at the extreme levels of the curve. This distraction is automatic, and as a matter of fact it is impossible to apply it as the wires are sliding on the rod. The problem with spinal translation is that it cannot control rotation, neither with screws nor with hooks. Frontal X rays show that the anterior spine will always be located outside the rods pulling the posterior arch. This technique was improved by Asher and Chopin, who introduced screws and hooks. However it is still very difficult to decide on which side one should work, i.e. concave or convex side. The problem of rotation is still unsolved as anterior spine projection onto the x-rays is still next to and outside the rods.

Rod rotation is the most popular technique nowadays as it allows rather good global correction. However, the thoracic correction does not follow the pathology path and therefore has no impact of vertebral rotation. This technique allows only slight adjustments, often very difficult to perform especially in the frontal plane. In 1993, we reviewed 52 scolioses operated with the rod rotation technique. All patients had undergone pre- and post-operative CT scan, so we could estimate the rotation correction. The results were highly disappointing as the vertebral rotation at the LEV (lower end vertebra) decreased of only 2.3°, while at the UEV (upper end vertebrae) level it was 1.1° higher after surgery, and at the apex level it remained almost unchanged (0.4° smaller). In conclusion, correction was obtained by vertebral translation, horizontalisation, forward and backward pushing of the vertebra, without any derotation. Several examples clearly reflected this mechanism, proved by the mobilization of the vertebrae with regard to the aorta.

When looking at the path described by the vertebra, one can easily notice that the different techniques described above do not allow to follow the deformity path. Thus, the thoracic vertebra goes frontward and turns to the right. This circular movement has a posterior centre of rotation. Vertebral translation does not follow this path as it moved about the arch cord. The rod rotation performs a circular movement about an anterior centre of rotation. The correction and deformity paths describe an ellipse. We can conclude that these techniques will lead to high constraints within the spine. Hence the risk of neurological structures damage during correction manoeuvres.

At the lumbar level, the apex moves backwards and to the left. Thus, it will describe an arch about a posterior rotation centre. The vertebra traction will move along the cord of this arch while the rod rotation will strictly follow the reverse pathology path. As the convex rod is linked to a hook or a screw, it will lead to a combined force of internal traction and anterior push. This convex push increases rotation by turning the screw in the sense of pathologic deformity. Therefore, the projections of the screws on the frontal x-rays will be oriented outside the rod, while the normal axis of the pedicle is about 20° oblique oriented toward the inside.

In Situ Contouring: Given these conclusions on the failure of traditional methods, we tried to develop the in situ contouring for a more efficient scoliosis correction. We would like to remind surgeons that the technique was designed to give the shape of the spine to the rod in order to set the instrumentation up, then to give the shape of the rod to the spine in order to reduce the deformity. All surgeons performed in situ rod bending at least once in their practice without being aware of.

However, when performing in situ contouring, some security rules have to be strictly respected. First of all, the rod must be free to move, so implants must be closed around the rod but remain unlocked until the correction manoeuvres are finished. The rod mobility will allow the automatic spine stretching/shortening without dangerous constraints. Vertebrae must slide along the rod by means of the implants, i.e. screws and hooks, solidly attached to them. In other words, the spine, i.e. vertebrae, must be mobilised. To do so, the benders must be placed close to the implants. The other reason is to avoid high lever arms that would lead to high risky forces (loads).

The correction principles are based on the vertebrae movement in space in order to enable a frontal and sagittal correction while working into the axial plane. To do so, the rod must have specific mechanical features: initial short elastic and long plastic domains. The correction manoeuvres on the rod will modify this mechanical behaviour and at the end of the correction manoeuvres the plastic domain will decrease wile the elastic one will increase. An initially too elastic rod would require stronger manoeuvres with regard to the residual correction, which may present some supplementary risk for neurological structures.

The levels to be instrumented are selected as usual, as in situ contouring does not modify rules usually used in order to determine the strategic vertebrae. The strategic vertebrae are selected depending on the information provided by bending tests. Thus all discs that do not open in both directions will be included into the fused segment.

Thoracic scoliosis: Similar to the rod rotation, the working rod is concave one in the thoracic spine. In contrast with the rod rotation technique, every second vertebra will be instrumented, going as close as possible from the apex. As neither distraction nor compression is performed, laminar hooks are not compulsory anymore. In our practice, we use pedicular hooks above T10 and screws below T10.

The rod will be contoured towards the inside and backwards for all instrumented levels. These manoeuvres will allow the medialisation of the apex while restoring kyphosis. At the same time, these actions will lead to a derotation of the apex. The contouring manoeuvres are performed iteratively starting from the apex towards the limits of the curvature through successive manoeuvres in the frontal plane and in the sagittal plane. Contouring is over when required correction is obtained and when the rod modified its mechanical behaviour and became too elastic to allow further contouring.

The apex follows the deformity path. Thus the vertebra moves backwards and towards the inside, describing a circular movement similar to the deformity path in the opposite sense. Therefore, three-dimensional correction of both mild and severe (> 100°) thoracic scolioses. However, the purpose of the surgery should not be to have a straight vertical rod, but to obtain the best possible spinal balance with the best possible correction in the three planes.

Lumbar scoliosis: Lumbar scoliosis may also be treated by in situ contouring. In this case, the working rod is the convex one. This rod will be bent towards the inside and forwards, thus enabling the lordosis restoration and the medialisation of the apex. These combine manoeuvres should lead to derotation. However, similarly to the rod rotation technique, forward bending will make the apex move in the pathological direction, thus increasing rotation. Thereby, it is paramount that screws turn simultaneously with the contouring manoeuvres. Only this combination of movements will provide with a three-dimensional correction.

To do so, derotation blocks are placed on the screws heads so that the assistant can turn them while the surgeon is performing the forward contouring manoeuvres that will allow lordosis restoration. This mobilization perfectly follows the deformity path and replaces the spine between the rods. This technique may be used both for mild and severe scoliosis correction in the three planes.

To facilitate correction and to maintain it on a long term basis, posterior release and posterior fusion may not always enough. In this case, anterior release and grafting may be required. Anterior approach may be facilitated by video assistance. Thoracoscopy will be preferred between T3 and T11, while video assistance is recommended for the thoracolumbar and lumbar regions. Anterior release associated with in situ contouring does provide significant correction especially in severe scoliosis as well as in stiff curvatures in the adult.

Three Dimensional Validation in Practice: Theory is nice but validation in practice is compulsory in order to verify our hypotheses. To check the validity of our statements, Raphael Dumas, PhD, performed a biomechanical analysis of the surgical correction by in situ contouring technique. He studied 20 scoliotic patients by means of stereoradiographic three-dimensional reconstruction. The stereoradiographic reconstruction technique is based on the identification of anatomical landmarks on frontal and sagittal x-ray films, previously acquired in a calibrated radiological environment equipped with a 90° turning table. This method provided us with three-dimensional reconstructions of spines allowing for an accurate measurement of vertebral rotations. Indeed, vertebral rotations must be measured in standing position, especially in the pre-operative examination, and has to be expressed in a fixed referential. These requirements could not be met with the traditional methods, i.e. CT scan. Three-dimensional reconstructions also provide us with an axial view of the whole spine, while allowing a comparison between the post-operative and pre-operative vertebral rotations at each level. We also calculated the intervertebral rotation. This rotation is maximum at the end vertebrae levels and minimum at the apex level. It is totally independent from the reference axis as the trunk movement will not alter the relative position of adjacent vertebrae. We actually consider that intervertebral angles are paramount for the estimation of the deformation severity as well as of the obtained correction. In our series (20 scoliotic patients) we observed a maximal rotation at the thoracic apex level (17.3°) and at the lumbar apex one (19°). The correction gain obtained was 11.3° at both levels. The intervertebral rotation had a maximum value at the limit vertebrae levels, i.e. 8.9° for thoracic superior level, 11.3° at the thoraco-lumbar junction and 7.3° at the inferior lumbar level. The correction obtained in these three regions was respectively 7.2°, 8.9° and 6°. We developed a detorsion index that corresponds to the difference between post-operative and pre-operative sums of intervertebral rotations of vertebrae within the organic curvature pondered by the pre-operative sum. The detorsion index at the thoracic level is 52% while at the lumbar level it is 85%. One can note that the thoracic detorsion is quite disappointing.

We could consider that the pedicular hook prevents from important detorsion in the thoracic spine, as it will not allow important derotation of vertebrae. This is why we had to design a new pedicular implant that was meant to provide bilateral support during correction manoeuvres. The so called bipedicular implant is linked to the vertebra at the costo-vertebral joint level holds the pedicle on its lateral side. This new implant enables a double action, i.e. posterior traction combined with concave medialisation and convex push. Thus the vertebra moves as a wheel, describing a global movement of derotation.

We have used this implant for two years now and we had no particular drawbacks as far. No tolerance problems were noted either. Derotation blocs allow for the combination of rotation movements at the thoracic and lumbar levels while the rod is contoured to reach the best possible curve correction.

Conclusion: The in situ contouring has been used for 10 years now. It is not just a physical gesture; it is a whole new philosophy of reduction, a new way of thinking in spine surgery. In situ contouring replaces vertebra in its initial spatial context while replacing the surgeon in the best position to create after thorough reflection on the pathological mechanism. The in situ contouring may be successfully used not only for scoliosis correction but also for other deformities, especially sagittal ones such as hyperkyphosis, fractures, malunions and lumbar degenerative deformities.

Introduction: There are few long-term studies after Zielke ventral derotation spondylodesis (VDS). We present a minimum 17 year follow-up study to assess factors predicting distal adjacent disc degeneration.

Material/Methods: Twenty-eight patients with thora-columbar AIS operated in 1982 have been retrospectively evaluated. Mean age 16,3 years, minimum follow-up 15 years. Anterior fusion was performed with rib graft.

Results: Mean pre-op Cobb angle was 65 ± 23°, post-op correction rate was 61,2 ± 12,4%. Mean angulation of end vertebra was 32 ± 10°, post-op corrected to a mean of 8° (correction rate 79%). Mean post-op Th10/L2 kyphosis was 10°. Rod breakage was seen in 17 patients.

Conclusion: Thoracolumbar kyphosis was associated both with proximal implant breakage and with segmental lordosis and degeneration of the distal adjacent segment. Disc angulation in the AP plane seems to be good tolerated. Anterior support with iliac bone graft or cages is expected to overcome these complications.

Introduction: We believe the information given by a new 2D/3D low dose radiation system is useful to the spinal surgeon.

Method: This commercially developed system was evaluated over the past three years. We evaluated 150 patients, with normal controls, using two prototypes. We compared it with a CT scan for accuracy in 2D and 3D reconstruction and for radiation doses.

Results: We found various advantages of this system over CT scanning:

Reductions in radiation exposure of x8 to x10 fold in 2D, and x800 to x1000 in 3D.

Overall it provides a new approach to assessing spinal deformity both in the horizontal plane and in volumetric measurement.

Conclusion: his innovative method is clearly a help for both patients and surgeons.

Background: Unclear aetiology in scoliotic and kyphotic deformities of the spine are responsible for uncertainty in treatment options. To clarify aetiology a constant reference to what normal growth and optimal construction of the entire spine should be at the end of growth is lacking.

Examination of sitting children and consequent testing of muscular tightness can be useful in understanding the different disturbances of growth that keep the spine apparently away from an optimal configuration and thereby optimal function. Prolonged sitting of children exists only 200 years or less.

Goal:

- Better understanding of the role of the central nervous system, especially the cord and roots in proper and improper growth of the human spine.

Methods:

- Present obvious important and consistent clinical observations in children in sitting and supine position with early and advanced adolescent deformities, both kyphotic and scoliotic by photographic studies and video fragments.

Results: We discovered by alteration of our brace-configuration that applying lordotic forces exclusively on the thoracolumbar spine gives excellent correction of kyphotic and scoliotic deformities progressing in adolescence. In a study of 32 patients with double curves > 25° all scoliotic curves significantly (p< 0,001) reduced by correcting with a forced lordotic fulcrum.

Extended clinical examination of children with proven or suspected spinal deformities revealed a complex of consistent findings in different sitting positions and functional tests in supine and standing positions.

Discussion: By looking for scientific support for these phenomena in (bio-)mechanical literature the work of Milan Roth was disclosed in his complete width. His embryologic studies, (neuro) anatomical and radiological findings with their explanations, alongside interesting cadaver-, mechanical- and neuro-anatomical experiments and models can bring his concept of neuro-spinal relationship in growth and misgrowth back to orthopaedic daylight. Even Nicoladoni saw a century ago that a cascade of structural alterations take place around the “core”-unit of the spine: the boundaries of the central canal to let it stay on its place and in the shortest configuration possible in scoliosis, by suspected tensile and compressive forces.

Anatomical and biomechanical consequences of keeping the spine upright in standing, but more important in the sitting positions seems to fit. Children do sit for prolonged periods only in the last one or two centuries!

It can be shown that the presence of these tension related clinical signs are easily leading to high compressive forces with deformation of the ventral parts in the TL-junction while sitting In literature evidence of torsion facilitating anatomical features can be found to clarify why some spines deform in scoliosis an not in pure kyphosis

Conclusions: By recognising positive effects of creating lordosis at the thoracolumbar junction of the spine and consistent clinical findings in early deformations scientific support was found by early experimental work of Roth. With a leading role of the central nervous system in growth of the spine of standing and sitting vertebrates by steering a tension based system, deformation can be understood as adaptations. Consequences for preventive measures and therapeutic strategies in deformities seems inevitable.

Objective: To evaluate the final result of surgical correction of AIS depending on preoperative spinal mobility and the type of procedure.

Summary of background data: To our knowledge no report has clearly demonstrated the role of different types of surgery in the final result of correction of deformed thoracic spine in AIS.

Materials and Methods: This is a retrospective, clinical study of patients with AIS and thoracic curves treated with CDI (hooks only) in the department of spinal surgery for children and adolescents of Russian Republican Spinal Centre from 1996 to 2005. Inclusion criteria included:

diagnosis of AIS King type II and III,

A total of 247 patients met the inclusion criteria and they were divided in two groups:

thoracic curve less than 90° and

In the group (A) there were 168 patients (male/female – 11/157, mean age 15.3 years), in the group (B) – 79 patients (male/female – 8/71, mean age 15.5 years). Coronal curve flexibility was assessed on supine side-bending AP radiographs. According the type of surgical technique the patients were divided in four groups:

I - CDI correction

All the operations in the groups III and IV were performed in one session.

Results: In the group (A) mean thoracic curve before surgery was 66.8°, on the side-bending films 42.9° and after surgery 26.0°. The corresponding data according the type of surgery are presented in Table1.

So, CDI adds only 9.1° to side-bending correction (Gr. I) and skeletal traction gives 5.8° more (Gr. II). Anterior release with CDI improves preoperative correction by 14.7° (Gr. III) and the same procedure with skeletal traction – by 30.0° (Gr. IV). Consequently the part of the skeletal traction varies from 5.8° to 6.2°. Anterior release in its turn gives 14.7° of additional correction per se and 20.9° with skeletal traction.

In the group (B) mean thoracic curve before surgery was 109°, on the side-bending films 90.6° and after surgery 54°. The corresponding data according the type of surgery are presented in Table 2.

So, CDI adds 26.3° to side-bending correction (Gr.I) and skeletal traction gives only 1.9° more (Gr.II). Anterior release with CDI improves preoperative correction by 25.9° (Gr.III) and the same procedure with skeletal traction – by 40.6° (Gr.IV). Consequently the part of the skeletal traction varies from 1.9° to 14.7°. Anterior release in its turn does not give additional correction per se and 12.2° – with skeletal traction.

Conclusion: Our study supports the data of Delonne et al. (1998) that the instrumentation per se does not play the principal role in achieving final correction in AIS surgery. Skeletal traction and anterior release are of great importance as well. The second deduction is that curve correction is defined mainly by the volume of surgical procedure not by the preoperative mobility on side-bending films.

Study design: A retrospective evaluation of screw position after double rod anterior spinal fusion in idiopathic scoliosis using computerised tomography (CT).

Objective: To evaluate screw position and complications related to screw position after double rod anterior instrumentation in idiopathic scoliosis.

Summary of Background Data: Anterior instrumentation and fusion in idiopathic scoliosis is gaining widespread use. However, no studies have been published regarding the accuracy of screw placement and screw related complications in double rod and double screw anterior spinal fusion and instrumentation in idiopathic thoracolumbar scoliosis surgery.

Methods: CT examinations were performed after anterior spinal fusion and instrumentation in 17 patients with idiopathic scoliosis. The vertebral rotation at each level was measured. At each instrumented level the position of the screw and the plate relative to the spinal canal, relative to the neural foramen and relative to the aorta was measured. Complications related to screw position were registered.

Results: 189 screws in 17 patients were evaluated. The average age of the patients was 31 years (range 15–53 years). Fourteen patients had a left convex thoracolumbar curve and three patients a right convex thoracolumbar curve. The mean lumbar apical rotation preoperatively was 27°. Malposition occurred in 23% of the total number of screws. Three screws were in the spinal canal (1%). This resulted in pain in the right leg. However, electromyography showed no abnormalities. On three levels there was contact between the instrumentation and the aorta. No vascular complications did occur. 113 screws (ten patients) were placed under fluoroscopic guidance and 76 screws (seven patients) were placed without use of fluoroscopy. No complications related to screw position were observed in the group in which the screws were placed under fluoroscopic guidance.

Conclusions: Adequate placement of two screws in the vertebra in idiopathic scoliosis is a technically demanding procedure, which results in frequent malposition, fortunately with a low risk of neurological and vascular complications.

Introduction: In this study we focus on idiopathic scoliosis with a primary thoracic curve and a secondary lumbar curve. We were interested in how the lumbar curve corrects following selective thoracic fusion and whether one can predict the correction of the lumbar curve. In the literature it is said that the lumbar curve spontaneously corrects to balance the thoracic curve after selective thoracic fusion. Because of these findings we postulate there should be a correlation between the correction of the lumbar and thoracic curve of the scoliosis.

Recently we showed in patients treated with Harrington instrumentation with sublaminar wiring (second generation technique) that the correction of the lumbar curve was not a reflection of the thoracic correction. So it is interesting to know whether with the use of third generation instrumentation techniques and more sophisticated classification systems the correlation of the unfused lumbar cure becomes more predictable.

Objective: To establish whether in primary thoracic idiopathic scoliosis treated with selective thoracic fusion using CD instrumentation there is a significant correlation (p< 0.05) between the correction of the thoracic and lumbar curve. And to assess whether, in the in the individual patient, the lumbar modifier (A, B and C) according Lenke, can be used as a correct predictor of outcome results. The higher the correlation coefficient between the relative (%) corrections of the thoracic and lumbar curves, the higher the predictability of the correction of the unfused lumbar curve.

Material and methods: We performed a retrospective study on 38 patients with adolescent idiopathic scoliosis treated by selective thoracic fusion (CD instrumentation). There were 29 female and nine male patients. For radiographic evaluation we used the standing antero-posterior and lateral projections of the thoracic and lumbar spine, preoperatively and at least one year postoperative. We assessed the frontal and sagittal Cobb angles. The angles were all measured by the same investigator (second author).

Results: Using Pearson correlation analyses we found a significant correlation (p< 0.001) between the relative (%) corrections of thoracic and lumbar curves (table1). The correlation coefficient between the relative correction of the thoracic and lumbar curve decreased with the Lumbar modifier (A, B, C).

Conclusion: A significant correlation is present between the relative corrections of the main thoracic curve and the lumbar curve after selective thoracic fusion in idiopathic scoliosis. The recently introduced new classification system seems to be of great predictable value for the spontaneous correction of the lumbar curve. Depending on the curve-type, a different technique for predicting the outcome should be used.

Introduction: In rigid AIS, the main resistance for thoracic derotation are the anteriorly rotated ribs on the concavity. This study presents clinical and radiographic long term results of the CTP, which is a routine surgical procedure at the authors’ institution.

Material and Methods: Between 1996 and 1997 we have operated on 466 cases of scoliosis. 36 patients with thoracic AIS were evaluated. Technique: The ribs on the concave side are osteotomised close to the costo-transverse joint and elevated over the bended rod.

Results: Mean follow up was 6.4 y. Mean preoperative side bending flexibility was 21%. Mean correction rate was 68%, mean rib hump correction was 3cm. Mean loss of correction 4°. There was no neurological complication, and pulmonary morbidity was not increased.

Conclusion: In rigid thoracic scoliosis, a release of the concave ribs by means of the CTP can both significantly increase the extent of correction and contributes to an excellent cosmetic result.

Open anterior surgery, including release and instrumentation, is a widely used technique for correction of dorsal and dorsolumbar curves. In the past we have used various different devices to maintain correction. These include Dwyer cable, Zeilke rods, Webb-Morley rods, vertebral staples and the Kaneda system. Any of these can be combined with posterior correction, stabilization and grafting. Several of these techniques have been successfully adapted for the treatment of our cases in Egypt. We encounter severe deformities due to their late presentation.

Over the last five years we have used anterior endoscopic release. All had posterior instrumentation.

Results: We did anterior release in 20 scoliosis cases and corpectomy in 10 cases. These were compared with another twenty cases who were treated by open anterior and posterior surgery.

The results are very encouraging regarding degree of correction; hospital stay; and costs as compared with our historical series of conventional two-stage surgery. There are a number of constraints on using endoscopic techniques. Surgeons require long training and close co-operation. It is contraindicated in those cases with adhesions and patients unfit for one lung anaesthesia. We found the technique is safe and effective. We recommend it for treatment of rigid curves to gain good results and to reduce hospital costs.

Study design: Prospective study after minimally invasive anterior approach of the thoracolumbar spine in scoliosis correction.

Objective: To describe the technique and first results after minimally invasive anterior approach of the thoracolumbar junction with insertion of double rod and double screw instrumentation.

Summary of Background Data: Minimally invasive techniques are used at many areas of surgery nowadays. Minimally invasive surgery should have the same correction potential as with conventional approaches. Possible advantages of minimally invasive surgery are small incisions, less tissue damage, less morbidity and an improved cosmetic appearance.

Methods: In this study we describe the technique and the preliminary results of minimally invasive open approach of the thoracolumbar spine with insertion of double rod and double screw instrumentation. A consecutive series of seven patients were included. All patients were female with a mean age of 16.7 years (range 10–28). The cause of thoracolumbar scoliosis was mixed.

Results: The thoracolumbar curve was 59° preoperatively and 22° at six months follow up (63% correction). The unfused thoracic curve was 40° preoperatively and 29° at six months follow-up. In the sagittal plane of the fused levels Cobb angle was 61° of lordosis preoperatively and 35° of lordosis at six months follow up. Lumbar lordosis of the unfused spine was 16° preoperative and 5° at six months follow up. Thoracic kyphosis was 33° preoperatively and 24° at six months follow-up. The average time of surgery was 6.6 hours (range 5.5–7hours). The average estimated blood loss was 764ml (range 350–1200ml). Average hospital stay was 11 days (range 5–14days), and average stay at the intensive care unit was 1.7 days (range 0–3 days). One minor neurological complication with complete recovery was observed.

Conclusions: Minimally invasive surgery has the advantage of less tissue damage, less morbidity and a better cosmetic appearance. With newer implants a good correction of the scoliosis can be achieved.

Anterior instrumentation is an established method of correcting King I adolescent idiopathic scoliosis. Posterior segmental pedicle screw instrumentation, with its more powerful corrective force over hooks, could offer significant advantages. The purpose of our study is to compare the results of anterior instrumentation versus segmental pedicle screw instrumentation in adolescent idiopathic thoracolumbar scoliosis. A retrospective analysis was conducted on 36 consecutive female patients with adolescent idiopathic thoracolumbar scoliosis who had surgery from December 1997. All had a minimum of two year follow-up. Eleven patients had posterior surgery performed on them.

Mean age at surgery was similar between both groups. Length of surgery was significantly shorter in the posterior group (189 minutes versus 272 minutes). Length of hospital stay was shorter in the posterior group (6.2 days versus eight days). Estimated blood loss, duration of analgesia, and ICU stay did not differ significantly between the two groups. No complications were encountered in both groups at latest follow-up. The magnitudes and flexibility of the thoracolumbar curves did not differ significantly between the two groups. The number of levels in the major curve was also similar between the groups. Fusion levels were shorter in the anterior group (mean 4.1 versus 5.0). The percentage correction of scoliosis was similar between the two groups at all stages of follow-up, being 74% at one week post-surgery, 70% at six months post-surgery, 68% at one year post-surgery and latest follow-up in the anterior group; and 71% at one week post-surgery, 67% at six months post-surgery, 68% at one year post-surgery, and 67% at latest follow-up in the posterior group.

Thoracolumbar sagittal alignment at T11 to L2 was maintained for both groups throughout the follow-up period. The incidence of proximal junctional kyphosis was higher in the posterior group (p < 0.01).

In conclusion, surgical correction of both the frontal and sagittal plane deformity are comparable to anterior instrumentation. Shorter length of surgery and hospital stay are the potential benefits of posterior surgery. Posterior segmental pedicle screw instrumentation offers significant advantage, and is a viable alternative to standard anterior instrumentation in idiopathic thoracolumbar scoliosis.

Posterior instrumented fusion is an established surgical treatment for majority of AIS cases. In the past decade, thoracoscopic instrumentation and fusion has emerged as a viable alternative to conventional posterior techniques in situations that require selective thoracic fusion. Most reports comparing the two techniques have focused on physician-based outcomes such as curve correction and maintenance of the surgical correction with both methods being comparable. Recently, the SRS-24 has been used to evaluate patient-based outcomes after scoliosis surgery. The instrument assesses seven equally-weighted domains that look at pain, self-image, general function, activity level, change in self-image and function post-surgery, and satisfaction with the procedure. It has been used to evaluate differences between AIS and normal patients, and in different degrees of AIS deformity. The instrument has not been used in comparing different methods of surgical treatment for similar curve types.

We applied the SRS-24 prospectively to our patients who had undergone either thoracoscopic (TG) or posterior (PG) instrumented fusion, and had been followed-up for at least 12-months postoperatively. There were 42 patients in TG and 42 patients in PG. The mean age at time of surgery, pre-operative Cobb angles, and number of spinal segments fused were similar in both groups. The mean follow-up period at the time the SRS instrument was administered was 26 (± 13.5) months for TG and 30.7 (± 12.1) months for PG. The postoperative Cobb angle on the latest follow-up was significantly better for TG compared to PG (17 versus 25.1 degrees, respectively; p < .001). Upon comparing the SRS domain scores between both groups, a significant difference was noted only in the patient satisfaction domain with TG scoring better than PG (p < .02).

The first four SRS-24 domain scores for TG and PG were also compared to the corresponding domain scores of 97 patients who had scoliosis but were not candidates for surgery (SG), as well as to the scores of 72 patients who did not have scoliosis (NG). SG, TG, and PG were comparable with regards to pain and all three were significantly lower compared to NG (F=14.828, p < .0001).

General function and activity level scores of TG were significantly lower compared to the other three groups (F=4.870, p < .003 and F=4.793, p < .003, respectively). Despite this, the self-image domain scores of both TG and PG were not significantly different from NG, with SG scoring significantly poorer compared to the other three groups (F=3.183, p < .02).

In summary, thoracoscopic instrumented fusion resulted in better curve correction compared to posterior instrumented fusion and was achieved with less spinal segments being fused. This was despite the finding that patients who underwent thoracoscopic surgery had lower physical function and activity level scores. Additionally, both surgical techniques resulted in patients whose perception of themselves was comparable to those patients who did not have scoliosis. The SRS-24 was not able to detect any differences between the two surgical methods in all domains except for overall patient satisfaction which was significantly better in the thoracoscopic group.

Thoracoscopic spinal instrumentation and fusion has emerged as a viable alternative to open anterior and posterior techniques for the treatment of thoracic adolescent idiopathic scoliosis. Furthermore, the morbidity associated with thoracoscopy is limited, and the cosmetic result more desirable because of the minimal skin and chest wall dissection required with this method. However, the technique is technically demanding and has been perceived as having a steep learning curve. The objective of our study is to anal the initial series of 50 patients performed by a single surgeon, with respect to the coronal and sagittal alignment on radiographs, as well as a review of the peri-operative data and complications.

Fifty consecutive patients who underwent thoraco-scopic instrumentation and fusion were divided into two groups for the purpose of this study: the first 25 cases (1st group) and the second 25 cases (2nd group). The minimum follow-up of these cases was 12 months (range 12 to 67 months). Data collected included the operative time, intra-operative blood loss, number of levels instrumented, length of the hospital stay, the number of days in the ICU, and the duration of analgesia.

No major complications, such as neurological deficit, vascular injury, or implant failure were observed. No significant difference was encountered between the groups in terms of age and menarche at surgery, pre-operative curve magnitude and flexibility, sagittal profile, as well as the number of levels in the curve pre-operatively. The second group had significantly better coronal deformity correction at one week post-operatively (9.5 degrees versus 16.3 degrees, p < 0.001), six months post-operatively (12.1 degrees versus 18.9 degrees, p < 0.001), and at latest follow-up (15.1 degrees versus 19.5 degrees, p < 0.05). The percentage correction of scoliosis was significantly better in the second group at one week postoperatively (p < 0.001), six months post-operatively (p < 0.001), and at latest follow-up (p = 0.014). The percentage change in thoracic kyphosis and lumbar lordosis after surgery was not significantly different between both groups at various times of follow-up. There was no difference between both groups with regards to the number of levels fused, hospital stay, and duration of parenteral analgesia. Operative time was significantly less in the second group (302 minutes versus 372 minutes, p < 0.001). Estimated blood loss was also less in the second group (170 cc versus 266 cc, p = 0.04). The length of ICU stay was also shorter in the second group (1.8 days versus three days, p = 0.004). From the loess (locally-weighted regression) fit, the learning curve is estimated to be 30 cases with regards to the operative time, ICU duration, and the coronal plane deformity correction.

The learning curve associated with thoracoscopic spinal instrumentation is acceptable. The complication rates remained stable throughout the surgeon’s experience. Thoracoscopic anterior instrumented fusion is a viable surgical alternative to standard posterior fusion and instrumentation for adolescent idiopathic scoliosis requiring selective thoracic fusion.

Introduction: Spinal deformities and scoliosis in particular, represent the most prevalent type of orthopaedic deformities in children and adolescents. At present, the most significant problem for clinicians is that there is no proven method or test available to identify children or adolescents at risk of developing AIS or to identify which of the affected individuals are at risk of progression. As a consequence, the application of current treatments, such as bracing or surgical correction, has to be delayed until a significant deformity is detected or until a significant progression is clearly demonstrated, resulting in a delayed and less optimal treatment. Among patients with AIS needing treatment, 80% to 90% will be treated by brace and 10% will need surgery to correct the deformity by spinal instrumentation and fusion of the thoracic and/or lumbar spine. About 15000 such surgeries are done every year in North America, resulting in significant psychological and physical morbidity. Moreover, there is no pharmacotherapy available to either prevent or reduce spinal deformities due mainly to our limited knowledge of AIS aetiopathogenesis. We have recently reconciled the role of melatonin in AIS aetiopathogenesis by demonstrating a melatonin signalling dysfunction occurring in a cell autonomous manner in cells derived from AIS patients exhibiting severe scoliotic deformities. This defect could potentially explain the majority of abnormalities reported in AIS since melatonin receptors and signalling activities are normally found in all tissues and systems affected in AIS, thus offering a very innovative and unifying concept to explain the aetiology of AIS. Moreover, several lines of evidence suggested that inactivation of Gi proteins by an increased phosphorylation of serine residues could be at the source of this signalling defect in AIS. The goals of that study were to assess the possibility to establish a molecular classification of AIS patients and to demonstrate the feasibility to correct this melatonin signalling defect in cells of AIS patients using therapeutic compounds.

Methods: Primary cell cultures were prepared from musculoskeletal tissues of AIS patients (n=150) and age- and gender-matched controls (n=35) obtained intra-operatively. An informed consent was obtained for each subject as approved by our Institutional Ethical Committee. The osteoblasts, the bone-forming cells, were selected to assess whether or not an alteration of melatonin signalling pathway occurs in AIS and accordingly to identify which component of the melatonin transduction machinery could be involved. Co-immunoprecipitation experiments with membrane extracts were performed to identify interacting molecules with key components of melatonin signal transduction machinery. The functionality of melatonin signalling was assessed by investigating the ability of Gi proteins to inhibit stimulated adenyl cyclase activity in osteoblast cultures. Inhibition curves of cAMP production were generated by adding melatonin to the forskolin-containing samples in concentrations ranging from 10-11M to 10-5M in a final volume of 1 ml of _-MEM media containing 0.2% bovine serum albumin (BSA) alone or in presence of 2.5 _M of therapeutic compound A or therapeutic compound B (the nature of both compounds tested cannot be disclosed at this stage). The cAMP content was determined using an enzyme immunoassay kit (Amersham-Pharmacia Biosciences). All assays were performed in duplicate. A non-parametric test, the Wilcoxon matched pairs test was performed to verify the significance between 2 means. Significance was defined as P< 0.05.

Results: Osteoblasts from patients with AIS showed a lack or a markedly reduced inhibition of forskolin-stimulated adenyl cyclase activity by melatonin generating three distinct response-curves corresponding to three functional groups. In order to identify candidate genes involved in AIS aetiopathogenesis, we focused our attention on known kinases and phosphatases modulating Gi protein functions and characterised their interacting partners. Interestingly, PKC_ was initially targeted owing to its property to phosphorylate Gi proteins in vitro. Indeed, in normal osteoblast interactions occurring between MT2 melatonin receptor and RACK1 (a cytosolic protein that bind to and stabilises the actives form of PKC and permits its translocation to different sites within the cells) and PKC_ were detected although those interactions among different AIS patients were altered. Interestingly, treatment with compound A or B rescued melatonin signal defect in cells derived from 36% and 47% of AIS patients respectively. Overall, melatonin signal transduction was restored in cells of 64% of AIS patients (23/36) when treated by one of these therapeutic compounds.

Conclusions: The functional classification of AIS patients is correlated at the molecular level by distinct interactions between key molecules normally involved in melatonin signal transduction in spite that these patients exhibited the same curve type (right thoracic, Lenke type 1). Collectively, these data strongly argue that traditional curve pattern classification is not a relevant stratification of AIS patients to identify its genetic causes. Moreover, using that molecular system we have demonstrated also the possibility to identify therapeutic compounds to rescue the melatonin signalling defect observed in AIS without any prior knowledge of mutations in any defective genes causing AIS because we are measuring a function.

Research project supported by La Fondation Yves Cotrel de l’Institut de France

Introduction: Over the last three years, we have demonstrated the complex role of melatonin, a hormone produces mainly in the brain, in the development of scoliosis and in particular by reporting for the first time that cells from AIS patients cannot respond to melatonin, which contrasted with similar cells isolated from healthy subjects. We have determined that this phenomenon is caused by chemical modifications affecting the activity of Gi proteins, a group of small proteins normally associated with both melatonin receptors. Interestingly, previous studies showed that melatonin deficiency could also induce a scoliosis suggesting that the asymmetrical growth of the spine in humans and in melatonin deficient animals could be caused by a common downstream effector regulated by melatonin. This study was then designed to determine and characterise the early biochemical, cellular and molecular changes underlying the formation of spinal deformities in growing pinealectomized chicken and in bipedal C57Bl/6 mice, a naturally melatonin deficient strain of mice.

Methods: For this study, 145 newly hatched chickens (Mountain Hubbard) were purchased at a local hatchery and divided into three distinct groups. First group, pinealectomized (n=100), underwent complete removal of the pineal gland. The second group, sham (n=20), underwent superficial cranial incision without the ablation of the pineal gland. The third group, control (n=25), the chickens did not undergo any surgical procedure. All surgeries were performed by the same surgeon between day three and five after hatching. At days 14, 21 and 28 chicken underwent radiographic examination with a DEXA bone densitometer (PIXImus II, Lunar Corp., Madison, WI). Each digital image was evaluated for the presence of scoliosis and the degree of curvature was measured. Cobb angle threshold value of 10° and higher was retained as a significant scoliotic condition. Blood samples (1 to 2 ml) were taken from a peripheral wing vein of each chicken (from 6 am to 9 am) at the age of 14, 21 and 28 days. Sera were collected by centrifugation and immediately stored at −80°C until assayed. Serum melatonin concentrations were determined using an ELISA method (IBL, Hamburg, Germany). At day 28, chicken were euthanised and tissues were collected to extract mRNA for expression analysis or proteins for subsequent detection. C57Bl/6 mice (n=50) were purchased from Charles-Rivers and bipedal mice were generated by removing the forelimbs and tail after weaning (three weeks old) according to a protocol approved by our institutional animal health care committee. Sera of AIS patients and matched healthy controls were also analysed to determine the levels of circulating P factor using an ELISA assay.

Results: Our results demonstrated a more dynamic variation of circulating melatonin level only in pinealectomised chicken developing a scoliosis, which allowed us to separate scoliotic chicken in two distinct groups. In the first group, the animals showed a biphasic response with a strong decrease of melatonin level between days 14 to 21, followed by a rapid recovery to almost reach the normal values at day 28. In the second group, pinealectomised chickens showed a linear decrease of circulating melatonin over the three-week period while, non-scoliotic pinealectomised chicken showed non-significant variations in melatonin concentration with values close to those obtained with the shams. At the molecular level, expression analysis demonstrated higher expression of a gene encoding a protein that has been termed P factor only in paraspinal muscles of pinealectomized chicken developing a scoliosis. Accumulation of P factor was also confirmed at the protein level by Western blot analysis. Bipedal C57Bl/6 mice, which are naturally melatonin deficient, developed also scoliotic deformities in a proportion of 45% over a two-month period. Interestingly, we observed that genetically modified mice devoid of P factor (n=60) or one of its receptor (n=40) in the same genomic background (C57Bl/6) cannot develop a scoliosis in the same conditions. Moreover, P factor circulating levels in scoliotic patients showed a 2–4 fold increase when compared to healthy matched individuals.

Conclusions: These results showed for the first time a more dynamic variation in circulating melatonin levels among pinealectomised chicken, which was unsuspected by previous studies. Interestingly, a transient decrease of circulating melatonin level was sufficient to induce scoliotic deformities during the first two weeks even if melatonin concentration was subsequently recovered a week later. This may explain why melatonin injection in pinealectomised chicken is not always efficient in preventing scoliosis. Taken together, these observations further suggest that a melatonin decrease below a certain threshold during a specific postnatal window may be sufficient to trigger a scoliosis and reconcile the data concerning AIS patients showing in most of the studies no significant variation when analysed at late stages. The study of early molecular changes in animal models also led us to identify a novel factor, which appears essential to initiate scoliosis through a specific signalling action. The clinical relevance of the P factor in AIS and related spinal syndromes is further strengthened by the detection of high levels of P factor only in scoliotic patients and could pave the way for the development of innovative diagnosis tools as well as the first pharmacological treatments to prevent scoliosis deformities in children.

Research project supported by La Fondation Yves Cotrel de l’Institut de France

Objective: Infants introduced to indoor heated swimming pools in the first year of life show an association with progressive adolescent idiopathic scoliosis (AIS). Similarly control children exposed in this way show an association with vertical spinous process asymmetry. A new method of assessment was used on these controls who were standing in an upright position. Overall, our evidence suggests that indoor heated swimming pools contain a risk factor that predisposes some infants to develop spinal asymmetries years later – progressive AIS in a few and off-vertical spinous process asymmetry in the many. What the risk factor may be and its possible portal of entry into the infant’s body are unknown and possibilities are examined. A subsequent new group of control children confirms the association of indoor heated swimming pools and vertical spinal asymmetry.

Risk factors: An irritant gas trichloramine (nitrogen trichloride) has been found to contaminate the air of indoor-chlorinated pools which Bernard et al link to asthma and chronic airway inflammation. Besides the lungs the skin in infants may provide another portal of entry of any chemical risk factors for spinal asymmetries. In connection with a chemical risk factor Nachemson anecdotally noted the development of scoliosis in salmon fry at a fish farm who were exposed to water contaminated after the re-painting of a water regulating dam.

Environmental epigenomics and disease susceptibility: Barker and his colleagues and others have shown that the origins of important chronic diseases of adult life may lie in foetal responses to the intrauterine environment and in infants to early postnatal life. Currently, there are British and US medical research projects to gather information on how human genes and environment interact over the years to cause disease; the British project is called Biobank. Another aspect concerns disease susceptibility by spotting gene variants in people who already have specific diseases. Do the suspected risk factors of indoor-chlorinated pools for spinal asymmetries need to be included in such studies? Is there potential for prevention?

In our earlier study we found 61% of the controls taken swimming in the first year of life had vertical spinous process asymmetry. In the subsequent smaller study the incidence even higher (83%).

Conclusions:

The evidence reported in our earlier paper suggests that infants introduced to indoor heated swimming pools in the first year of life show an association with spinal asymmetries including progressive AIS and in controls vertical spinous process asymmetry.

Genetic factors and impairment of central nervous system (CNS) are known factors in aetiology of adolescent idiopathic scoliosis. MRI pathology of CNS (brain asymmetry, syringomyelia) was found. Perinatal pathology could cause damage of CNS.

Material and method: Perinatal risk factors are evaluated in adolescent idiopathic scoliosis – AIS group (39 patients) compared with normal individuals – N (28 persons).

In the AIS group, the mean onset of right thoracic curve was 12,2 years, apex vertebrae were T7 – T11 (T8 in 8 cases, T8–9 in 5, T9 in 12 cases), mean Cobb angle measured 49,0 degrees (SD 14,500), thoracic kyphosis T3-T12 19,9 (SD 12,167), lumbar lordosis T12-S1 –53,1 (SD 8,338).

A questionnaire was created to identify parental age, diseases, mother diseases and remedies during pregnancy, pregnancy duration, child resuscitation, childbirth pathology, incubator, jaundice duration, diseases during the first year of life, beginning of sitting and standing, right or left handing. Results have been processed by software Statistica 7.1. StatSoft, Inc. (2005). For evaluation of potential difference between AIS and N groups two-sample t-test for continuous parameters was used. Two-sample t-test and Fisher test were testing the hypothesis that the values of parameters make no difference between two groups (on the 0,05 significant level).

Results: More children who required an incubator were found in AIS group – 4, N group – 1 (statistically insignificant). We found these statistically significant differences:

- Occurrence of familiar scoliosis in AIS group – nine out of 39, 0 in N group.

Conclusion: These finding confirm the importance of genetic factors and support the influence of CNS dysbalance factors in early childhood. The earlier sitting (in AIS group) could start the dysbalance of postural motor system. Further studies are necessary.

AIS has different image than paralytic scoliosis or scoliosis accompanying some diseases of the spinal cord in electromyographical and electroneurographical examinations (EMG and ENG). These differences are concerned to different progression, characteristic properties in skeletal system pathology or curves angles at the thoracic and lumbosacral spine.

Radiological diagnosis is not the only tool in detection, monitoring of progress and making easy to undertake a decision about the surgical scoliosis correction. The below presented algorithm of scoliosis monitoring with complex and repetitive (comparative) neurophysiological examinations facilitates the doctor’s decision about method of the conservative treatment or just the moment of surgical intervention [3, 14]. Neurogenic changes in muscles can be found in early stages of the spine deformation – usually when the Cobb’s angle is over 100 [1]. Vertebral rotation and curvature progression follow simultaneously leading to deformation of the spinal cord together with the local ventral roots compression and sometimes inflammation of them. The structure of the grey matter especially in the ventral horn changes its form more on the convex side of scoliosis. Cell bodies together with the axonal hillocks in the motoneuronal pools show deformations comparing to the analogical area of the concave side. This produce discrete unilateral axonopathy in both efferent fibers of peroneal and tibial nerves in scoliotic patients at the age of about 10. This can be found in electroneurographical (ENG) recordings of M and F potentials even at the angle of scoliosis of 100 [10, 14]. Both parameters of the amplitudes and conduction velocities in M-wave studies are decreased and the frequency of F wave recording is diminished what suggests pathological asymmetrical changes just at the level of the ventral root. That is why electromyographical (EMG) recordings show asymmetrical, according to the ventral root somatotopical innervation, selective (found only in some muscles) deficits in frequency and amplitude of motor units action potentials, predominantly in girls. These girls have scoliosis accelerating the most with angle changes of 50 per year [2] that rapidly deepens the neurogenic changes.

Other significant evaluation of the scoliosis acceleration is using the somatosensory evoked potentials (SEPs) for recording progression of pathology in the afferent transmission within the long ascending spinal cord pathways running in dorsal, dorsolateral and lateral funiculi [4, 5]. Changes in parameters more amplitude than conduction velocity from SEPs studies recorded at the cervical level are more visible on the concave than convex side of scoliosis. These changes are correlated with increasing the Cobb’s angle at the apical thoracic vertebrae (Th7–8) while peripheral sensory transmission remains only slightly disturbed [6, 7]. These changes were found to be twice greater when recording of SEPs was performed over cranially on the contralateral side of the scalp to the stimulation site at the ankle (tibial nerve than peroneal nerve fibers excitation) both in mothers and their daughters [4]. This points at the strong inhibition of the afferent transmission at the level of the brain stem (probably thalamus or medial lemniscus). During the comparative SEPs recordings at the cervical level, when parameters of waves change dramatically (or even they disappear), this may suggest that the lateral angle of scoliosis exceeded 450 with great acceleration of the torsion [9]. Somatosensory evoked potential recordings during the surgical correction of scoliosis showed only rarely the immediate improvement of the afferent transmission [7, 8, 11]. However, they make sure a surgeon about lack of blockade within the spinal pathways which comes from derotation and distraction procedures performed on the spine during implantation of the corrective instrumentation. First visible results of improvement in the SEPs parameters recorded postoperatively are usually seen a week after the surgery [14].

The above analogical phenomena but referring to the efferent transmission were shown in motor evoked potentials studies which were induced with the magnetic field (MEP) in areas of motor cortex and recorded from centres of cervical and lumbosacral spinal cord as well as from nerves and muscles of upper and lower extremities [12,13, 15].

Usually when AIS reaches the Cobb’s angle of 200 at the age of 25 and does not progress more it can be assumed, that its development is finished. In these patients the signs of neurogenic changes found in EMG examinations performed in lower extremities, paravertebral and gluteal muscles do not progress, too [14].

Introduction: A parameter in surface topography was developed to measure left-right differences in back surface of different scoliosis patterns, and to relate these to biological asymmetry and the evolution of deformity. Because of the close association between scoliosis and growth, the hypothesis that scoliosis is growth, that it affects not just the spine but the whole body and that it falls into well-described biological patterns of asymmetry, was explored.

Methods: The new measure compares the positions of three points (mid way between the first thoracic vertebra and axilla, and one and two thirds from axilla to posterior superior iliac spines) on either side of the mid-line, reflecting right onto left and expressing the displacement along Cartesian axes in millimetres. The purpose is to measure size and growth differences at diagnosis and during follow-up. Statistical analysis was of prospectively collected topographic, radiographic and clinical data. There were three groups, all female: 1. mild asymmetry (N=84, no radiograph); 2. thoracic (N=65, mean Cobb angle 61.4°±19.5) and 3. thoracolumbar or lumbar (N=40, mean Cobb angle was 51.8°±23.0). Comparisons were made between each group and theoretically perfect symmetry (test value zero). Correlations with Cobb angle change over time were analysed.

Results: Groups one and three showed directional asymmetry in the coronal plane only, and were not statistically different from each other. Group two showed directional asymmetry at all levels, the side of the scoliosis convexity being larger in all three dimensions (left-right, antero-posterior and cranio-caudal). Changes in Cobb angle correlated with statistical significance with change in the vertical height of the convex side.

Conclusions: This topographic measure was developed specifically to quantify the asymmetry of the back surface, to assign it to a biological pattern and to observe how it might change during growth and scoliosis evolution. All levels of asymmetry, the minor as well as the true scoliosis, showed directional asymmetry (normal distribution of left-right differences about a mean that is not zero, genetically determined) which suggests an origin of scoliosis lying in the biology of growth and the evolution of morphology, rather than in a particular disease process. This asymmetry does not cause scoliosis: it is the result of asymmetric growth processes, it is scoliosis. The relevance of this view is that it obviates the need for an identifiable disease process, as scoliosis is a non-specific developmental response to physiological stress. It is the destabilising of the genetic control “programme” that operates in the growing organism to produce an adult phenotype which is an accurate expression of its genotype. This interpretation can explain observations of natural history that currently cause problems viz. the association with growth and development, lateralisation, increased incidence with other medical conditions, and female predominance, the recurrence of deformity after surgical correction and perhaps even the difficulty in reaching a final conclusion on the efficacy of brace treatment.

Background: The neurocentral junction often has been identified as a potential cause of adolescent idiopathic scoliosis (AIS). Disparate growth at this site has been thought to lead to pedicle asymmetry, which then causes vertebral rotation in the transverse plane and ultimately, the development of scoliotic curves.

Objectives:

To develop a model that incorporates pedicle growth and growth modulation into an existing finite element model of the thoracic and lumbar spine already integrating vertebral growth and growth modulation

Methods: The model was personalised to the geometry of a non-pathological subject and used as the reference spinal configuration. Left/right asymmetry of pedicle geometry (i.e. initial length) and left/right asymmetry of the pedicle growth rate alone or in combination with other AIS potential pathogenesis (anterior, lateral, or rotational displacement of apical vertebra) were simulated over a period of 24 months. The Cobb angle and local scoliotic descriptors (wedging angle, axial rotation) were assessed at each monthly growth cycle.

Results: Simulations with asymmetrical pedicle geometry did not produce significant scoliosis, vertebral rotation or wedging. Simulations with asymmetry of pedicle growth rate did not cause scoliosis independently and did not amplify the scoliotic deformity caused by other initial deformations tested by Villemure (2004).

Discussion and Conclusion: The results of this biomechanical model do not support the hypothesis that asymmetrical neurocentral junction growth is a cause of AIS. This concurs with recent animal experiments in which neurocentral junction growth was unilaterally restricted and no scoliosis, vertebral wedging or rotation was noted. With regards to addressing the aetiology of scoliotic curve development, biomechanical modelling represents a powerful tool to investigate cause and affect relationships since AIS patients typically present to the scoliosis clinic well after curves have manifested.

Contact person and Presenter: Carl-Éric Aubin, Ph.D., Canada Research Chair “CAD Innovations in Orthopedic Engineering”, Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Canada, Tel: (514) 340-4711, ext. 4437; Fax: (514) 340-5867; E-mail: carl-eric.aubin@polymtl.ca

Patterns of extra-spinal skeletal length asymmetry have been reported for upper limbs [1] and ribcage [2] of patients with upper spine adolescent idiopathic scoliosis. This paper reports a third pattern in the ilia. Seventy of 108 consecutive adolescent patients referred from routine scoliosis school screening during 1996–1999 had lower spine scoliosis – lumbar (LS), thoracolumbar (TLS), or pelvic tilt scoliosis (PTS). Radiologic bi-iliac and hip tilt angles were both measurable in 60 subjects: LS 18, TLS 31, and PTS 11 (girls 44, boys 16, mean age 14.6 years). Cobb angle (CA), apical vertebral rotation (AVR) and apical vertebral translation from the T1-S1 line (AVT) were measured on standing full spine radiographs (mean Cobb angle 14 degrees, range 4–38 degrees, 33 left, 27 right curves). Bi-iliac tilt angle (BITA) and hip tilt angle (HTA) were measured trigonometrically and iliac height asymmetry calculated as BITA minus HTA (corrected BITA=CBITA) and directly as iliac height asymmetry. Iliac height is relatively taller on the concavity of these curves (p< 0.001). CBITA is associated with Cobb angle, AVR and AVT (each p< 0.001).

Conclusion: The relatively taller concave ilium may be 1) real from primary skeletal changes or asymmetric muscle traction on iliac apophyses [3], or 2) apparent from rotation/torsion at the sacro-iliac joint(s).

In schoolchildren screened for scoliosis about 40% have minor, non-progressive, lumbar scolioses secondary to pelvic tilt with leg-length and/or sacral inequality [1] not reported with preoperative thoracic curves [2]. Forty-nine of 108 consecutive adolescent patients referred from routine scoliosis school screening during 1996–1999 had lower spinal scoliosis with measurable radiological sacral alar and hip tilt angles – lumbar scoliosis 18, thoracolumbar scoliosis 31 (girls 41, boys 8, mean Cobb angle 16 degrees, range 4–38 degrees). In standing full spine antero-posterior radiographs measurements were made of Cobb angle and pelvic asymmetries as sacral alar and iliac heights (left minus right). From anthropometric measurements derivatives were calculated as ilio-femoral length (total leg length minus tibial length) and several length asymmetries, namely: ilio-femoral length asymmetry, total leg length inequality and tibial length asymmetry (all left minus right). Ilio-femoral length asymmetry correlates significantly with sacral alar height asymmetry (girls negatively r= − 0.456, p=0.002, boys positively r=0.726 p=0.041) but not iliac height asymmetry (girls p=0.201) from which three types are identified. Total leg length inequality but not tibial length asymmetry in the girls is associated with sacral alar height asymmetry (r= − 0.367 p=0.017 & r=0.039 p=0.807 respectively). Interpretation is complicated by total leg lengths each including some ilium in which there is asymmetry [3]. But lack of association between ilio-femoral length asymmetry and iliac height asymmetry suggests that the femoral component is more important than iliac component in determining the associations between sacral alar height asymmetry and each of ilio-femoral length asymmetry and total leg length inequality.

Conclusions:

Sacral alar height asymmetry and leg length asymmetries. The evidence suggests that sacral alar height asymmetry is not secondary to the leg length inequalities at least in most girls (negative correlations) and is more likely to result from primary skeletal changes in femur(s) and sacrum.

In idiopathic scoliosis the detection of extra-spinal left-right skeletal length asymmetries in the upper limbs, ribs, ilia and lower limbs [1–7] begs the question: are these asymmetries unconnected with the pathogenesis, or are they an indicator of what may also be happening in immature vertebrae of the spine? The vertebrate body plan has mirror-image bilateral symmetries (mirror symmetrical, homologous morphologies) that are highly conserved culminating in the adult form [8]. The normal human body can be viewed as containing paired skeletal structures in the axial and appendicular skeleton as a) separate left and right paired forms (e.g. long limb bones, ribs, ilia), and b) united in paired forms (e.g. vertebrae, skull, mandible). Each of these separate and united pairs are mirror-image forms – enantiomorphs. In idiopathic scoliosis, genetic and epigenetic (environmental) mechanisms [9–11] may disturb the symmetry control of enantiomorphic immature bones [12–13] and, by creating left-right endochondral growth asymmetries, cause the extra-spinal bone length asymmetries, and within one or more vertebrae create growth conflict with distortion as deformities (= unsynchronised bone growth concept) [14].

Conclusion: This enantiomorphic disorder concept applied to the axial skeleton during infancy, juvenility and adolescence – through reductionism into the molecular mechanisms of growth plate responses to different hormones at successive phases of development – provides a new theoretical insight to explain the whole body deformity of AIS. The concept suggests preventive surgery on spine and ribs.

In subjects with lumbar, thoracolumbar or pelvic tilt scoliosis no pattern of structural leg length inequality has been reported [1]. Forty-seven girls of 108 consecutive adolescent patients referred from routine scoliosis school screening during 1996–1999 had lower spinal scoliosis – lumbar (LS) 17, or thoracolumbar (TLS) 30 (mean Cobb angle 16 degrees, range 4–38 degrees, mean age 14.8 years, left curves 25). The controls were 280 normal girls (11–18 years, mean age 13.4 years). Anthropometric measurements were made of total leg lengths (LL), tibiae (TL) and feet (FL) by one observer (RGB) and asymmetries calculated for LL, TL and FL, as absolutes and percentage asymmetries of right/left lengths. There are no detectable changes of absolute asymmetries with age for LL, TL or FL in scoliotic or normal girls. Asymmetries are found in scoliotic girls compared with normals with relative lengthening on the right for each of LL (0.95%) and TL (0.99%) (each p< 0.001), but not FL (0.38%).

Conclusion: The relative lengthenings in the right leg are unrelated statistically to the severity or side of the lower spinal scoliosis; the cause is unknown and may be related to posture – free standing on the right leg [2] – to neuromuscular mechanisms, or to primary skeletal changes in growth plates of femur(s) and tibia(e).

Nachemson [2] suggested that there are more girls than boys with progressive AIS for the following reason. The maturation of postural mechanisms in the nervous system is complete about the same time in boys and girls. Girls enter their skeletal adolescent growth spurt with immature postural mechanisms. So, if they have a predisposition to develop a scoliosis curve, the spine deforms. In contrast, boys enter their adolescent growth spurt with mature postural mechanisms so they are protected from developing a scoliosis curve. We termed Nachemson’s concept the neuro-osseous timing of maturation (NOTOM) hypothesis and used it to propose a possible medical treatment for idiopathic scoliosis by delaying puberty through the pituitary using gonadorelin analogues as in idiopathic precocious puberty [3,4].

The prevalence of scoliosis is reported to be increased in rhythmic gymnasts (RGs) in Bulgaria [5] and in ballet dancers (BDs) in the USA [6]. Both groups exhibit delayed puberty, which, at first sight, nullifies the NOTOM hypothesis for idiopathic scoliosis. There are similarities between scoliotic RGs and BDs that include intensive exercise from a young age, dieting, delayed menarche, increased scoliosis prevalence (RGs 12%, BDs 24%), mild scoliosis curves (10–30 degrees), and presumably generalised joint laxity. Other differences in addition to country of origin and exercises, include certain anthropometric features and importantly in RGs, thoracolumbar and lumbar curves and, in BDs, right thoracic curves. While constitutional and environmental factors may determine the scoliosis, the different curve types in RGs and BDs suggest that the exercise pattern over many years determines which type of scoliosis develops, although not the curve severity.

Conclusion: The view that scoliotic RGs should be included in a group of sports-associated scoliosis separate from idiopathic scoliosis [5] is supported. We suggest that most BDs who develop mild-moderate scoliosis do not have idiopathic scoliosis but a scoliosis related to intensive exercises over many years acting on a particular phenotype and genotype, similar to the sports-associated scoliosis. In this context the delayed puberty of RGs and BDs with scoliosis does not nullify the NOTOM hypothesis. There is a need to focus research on such subjects who have defined constitutional and environmental factors related to their scoliosis.

It is customary to analyse scoliosis as a mechanical failure: first there is a straight spine (=normal), then an habitual and collapsing posture (=disease) and finally, structural remodelling (Hueter-Volkmann effect = scoliosis). This hypothesis makes two practical predictions:

There is a disease process causing the pathological posture. The purpose of gatherings such as this is to identify this pathology, thus far without success.

The failure of school scoliosis screening to achieve this end is well documented, but the consequence for the underlying hypothesis has not been analysed. Screening failed, not because it was unable to detect scoliosis, but because scoliosis did not behave as the hypothesis predicted.

Disease process: All theories presume some form of neurological or muscular deficit as the final pathway but while the variety is wide, e.g. (historically) anterior poliomyelitis; more recently proprioceptive defect, melatonin or calmodulin disorder, there is no clear evidence for such a deficit in adolescent idiopathic scoliosis (AIS). Of 1342 screening referrals to this centre, 10 had a neurological diagnosis (most of which were already known to the patients) and 598 had radiologically confirmed AIS. In contrast, 1707 referrals to the general clinics included 410 syndromic cases and 420 AIS. Patients with a neurological problem, by and large, find their own way to medical attention. The hypothesis does not explain the natural history or the aetiology, and awkward observations, such as the association with growth (Goldberg et al Spine.18(5):529–535.1993, Eur Spine J.2:29–36.1993 and, most recently, Ylikoski M. Journal of Pediatric Orthopaedics B.14:320–324, 2005) or the higher incidence in ballet dancers (Warren et al. New England Journal of Medicine.314(21):1348–1353.1986) and rhythmic gymnasts (Tanchev et al. Spine.25(11):1367–1372.2000) are ignored.

Screening: Screening programmes (e.g. Goldberg et al., Spine.20(12):1368–1374, 1995) showed that there was no precise demarcation between “scoliosis” and “normal,” and that there was no benefit in terms of the need for surgical correction from screening or bracing, (Goldberg et al. Spine.26(1):42–47, 2001).

Discussion: his information has been in the public domain for some years and, in the meanwhile, there have been huge advances in biology and medicine which must have relevance. When the predictions of a hypothesis are not confirmed, that hypothesis must at least be re-examined, and it is not necessary to wait until a replacement can be suggested. The undisputed aspects of scoliosis, such as association with growth rate and maturation, lateralisation, gender predominance, normal distribution of Cobb angle and asymmetry over the wider population, essential health and normality of those with even severe deformity, increased incidence in other conditions, all suggest a different model. This is an opportune time to pause and reconsider the underlying model of scoliosis in the light of what we have learned about scoliosis and what is now known in other disciplines about how morphology is determined and evolved.

Introduction: The aetiology of scoliosis is not known. Many different mechanisms have been suggested as playing a part in the development. Dysfunction of the segmental paravertebral muscles have been suggested to have some impact on the condition. It is known that the injection of botulinum toxin type B will paralyse muscles by blocking of the motor endplate. The effect has been shown to last up to three months. The experiment was designed to study if segmental muscles in the thoracic region of the spine in pigs play a role in the development of the spine.

Materials and Methods: Six seven days old piglets were used in the experiment. In the lower thoracic region in three levels on the left side the paraspinal muscles were infiltrated with botulinum toxin type B. It was used 10 units of Botox® on each level, a total of 30 units were used on each animal. It was taken care to infiltrate the different small muscles as the toxin does not spread readily to adjacent muscles. The pigs were then left for normal care and development. They all were assessed at four weeks intervals until they were sacrificed three months after initial injection. x-ray were then taken of the spine.

Results: During the follow-up there were no visible changes in the alignment of the spine. The piglets developed normally. On x-ray there were no signs of developmental disturbances and we did not see any signs of scoliotic development. If anything, there was the development of a long curvature in the thoracic spine. On examination there was clear atrophy of the segmental muscles in the injected regions.

Discussion: This experiment suggests that the development of the spine is not guided by either the presence or absence of muscle activation. The dose of Botox® applied to these small muscles should be more than adequate to stop nearly all muscle activity. The pig has a rapid growth period from seven days to three months. Any changes caused by muscle activation should have been detected in this period. It could be that the effect on fast growing animals is shorter than three months. Nevertheless we still saw muscle atrophy at time of sacrifice.

Background and methods: Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity in children, with a prevalence of 1–2%. The disease generally displays complex inheritance. Various family studies have produced many first reports of AIS susceptibility regions, but confirmation of these is lacking. In the present study we investigated extension of our own data, and reproducibility of other published results, by testing linkage in a new collection of fifty-four AIS families. Altogether fifteen candidate regions were evaluated in a two-stage design.

Results: Strongest results were obtained for linkage to microsatellite loci within a candidate region of proximal 8q previously identified by chromosomal breakpoint mapping. Although positive lod scores were obtained for other regions, none exhibited significance less than or equal to P = .05. Lod scores remained stable after analysis of an independent panel of SNP loci in the 8q candidate region and were strengthened with inclusion of additional affected family members (multipoint NPL = 3.02, P = 0.001). Two SNPs near the peak of linkage produced evidence of association to AIS susceptibility. Both SNPs are found within plausible candidate genes for AIS susceptibility.

Conclusion: These results support linkage of the 8q11-8q13 region to AIS susceptibility. Bashiardes et al. previously described a chromosomal break in the 8q11 region that disrupted the gamma-1- syntrophin (SNTG1) gene and segregated with AIS in an extended kindred. In that study, possible rare splice site mutations were identified an additional affected family and one sporadic case. The peak of linkage and association detected in this study appears to be distinct from the SNTG1 gene. This suggests the possibility that more than one gene in the region may contribute to disease. A more detailed analysis of the region encompassing this linkage peak, and the SNTG1 gene, is warranted in larger family collections.

Purpose: To compare the post-operative morbidity, of a novel vertical approach, with that of the standard transverse one, for procurement of Autologous bone graft from the iliac crest, for the purpose of cervical spine fusions.

Methodology: Patients undergoing procurement of bone graft from the iliac crest were prospectively randomised into two groups. The study group (18) underwent the procedure through a novel vertical approach, while the controls (22) had the standard transverse approach. Both groups were evaluated by a blinded observer at 1 month and 6 months postoperatively. The visual analogue pain score,(VAS), use of analgesics, disruption of cutaneous nerve function and local tenderness were recorded.

Results: The mean VAS in the study group was 2.5 and 4.4 in the control group one month postoperatively. This was reduced to 2.9 in the control group and 1.8 in the study group six months later. The study group had a lower incidence of local numbness (33.3 %) compared to (72.7%) in the control group one month after surgery. Use of analgesia after 6 months was lower in the study group (11.1%), compared to 50% in the control group 6 months post operatively. There was no significant difference between the two groups with regards to other parameters.

Conclusion: The vertical approach to the iliac crest is associated with lower morbidity and is an effective alternative to the standard approach.

Aim: To determine the incidence of adjacent level osteophytes in patients who have had anterior cervical fusion using an anterior cervical plate as compared to those who are fused without an anterior cervical plate.

Design: We retrospectively reviewed the lateral radiograms of sixty two patients who have had an anterior cervical fusion with a minimum follow up of twelve months.

Materials and methods: We looked for the development of adjacent level osteophytes in these patients at their final follow up, which was generally at the time radiological fusion. There were 27 patients in the first group who had an anterior cervical plate used to fix the vertebrae in addition to the Cervios cage, while the 35 patients in the second group in whom only a Rabea cage was used for the fusion. The mean follow-up was 20.6 months (range 12–48).

Results: 64.3% of the patients who had an anterior cervical plate developed adjacent level osteophytes while none of the patients who have had the fusion without the cage developed the osteophytes.

Conclusion: We found the patients who had an anterior cervical interbody fusion using a plate had a significant risk of developing adjacent level osteophytes while this is not seen in patients who do not have the plate for the fixation.

Background: The phenomenon of heterotopic ossification (HO) is a well-known complication of joint replacement surgery. However, the clinical associations and effects of HO in cervical arthroplasty are unclear. This study investigates the incidence of HO in cervical disc replacement, identifies potential associated risk factors, and assesses the relationship of HO with clinical outcomes.

Method: The patient population (n=90; 39 men, 51 women; mean age 45 years; range 26–79 yr; standard deviation, 9.8 yr) was acquired from the original multi-center, prospective, observational Bryan Disc Study by the European Consortium. The presence of HO was defined in accordance with the McAfee classification based on cervical lateral x-rays at 12 months post surgery and interpreted by an independent neurosurgeon and a radiologist. Secondary outcome measurements included Odom’s criteria and the Medical Outcomes Study Short-Form 36-Item Health Survey.

Results: 16 out of the total 90 patients (17.8%) experienced HO. 6 patients (6.7%) experienced Grade 3 and 4 HO. 10 patients’ (11%) artificial discs demonstrated movement of less than 2 degrees on flexion and extension cervical x-ray at 12 months post-operatively. 4 of these patients had HO of Grade 3 or 4. Male sex ([chi]² = 4.1; P = 0.0407) and older patients (P = 0.023; odds ratio = 1.10; 95% confidence interval = 1.01–1.19) were associated with development of HO.

Discussion: HO is known to restrict movement of large joint and lumbar disc replacements. Our study demonstrates male sex and older age as potential risk factors in development of HO after cervical disc arthroplasty. There is a strong association between HO and subsequent loss of movement of implanted cervical artificial discs. Failure to preserve motion may expedite the onset of symptomatic adjacent segment level disease making this an important complication requiring further investigation. Grade 3 or 4 HO limited movement in 4.4% of patients.

Introduction: Atlanto-Occipital dislocation is rare and usually fatal. Stabilisation is typically from Occiput to C2; sacrificing atlantoaxial movement. To preserve movement, screw fixation from the articular mass of C1 to the occipital condyle has been described. Amongst other structures, the hypoglossal nerve is at risk. No previous study has addressed the anatomy of the hypoglossal canal in relation to screw trajectory. We aim to identify landmarks to aid safe screw passage into the occipital condyle.

Methods: 20 dry skulls provided 40 hypoglossal canals (HCs) and 40 occipital condyles (OCs). No distinction was made between sex, race or age. 9 parameters were measured for each HC, and relation to skull base was noted.

Results: The mean length of the HC was 10mm (range 8 to 14). The extra-cranial foramen of the HC is located lateral to the intra-cranial foramen (30° range 19 to 45). 19 out of 20 skulls had HCs with intra-cranial foramina more caudal than their extra-cranial foramina, ie the HC angled cranially (22° range 7 to 51). 36 of 40 OCs were found to be wholly inferior to the rim of the foramen magnum, with 4 (in 2 skulls) whose bodies lay largely below, but extended above, this landmark. Every single HC studied was situated, in its entirety, superior to the rim of the foramen magnum.

Conclusions: The trajectory of the hypoglossal canal from its intra-cranial foramen is antero-supero-lateral. It is situated, in its entirety, superior to the rim of the foramen magnum. The thickest portion of the occipital condyle is antero-medial. Screw passage from posterior through the C1 articular mass ought to aim for the anterior, superior, medial quadrant of the occipital condyle, and should not pass cranial to the rim of the Foramen Magnum in order to minimise the risk to the Hypoglossal Nerve.

Aim: To compare the outcomes between two different surgical techniques for cervical myelopathy (skip laminectomy vs laminoplasty).

Methods: Cervical skip laminectomy is a new technique described by Japanese surgeons in 2000. The advantage of this procedure over the other conventional techniques is it addresses multilevel problem in a least traumatic way without need for instrumentation.

We are comparing the above two techniques with 25 patients in each group operated by 3 surgeons. The first group had conventional laminoplasty and the second group underwent the skip laminectomy. The groups were comparable in age, sex, pathology and clinical presentation. Both these group had clinical outcome measurements using SF 12 questionnaires, pre and postoperative clinical assessment with standard tools performed by independent surgeon and a specialist spinal physiotherapist. We also routinely performed pre and postoperative MRI scans to assess the adequacy of decompression.

Results and Conclusion: here was no significant difference in the outcome of these patients in terms of the operative technique, hospital stay, clinical and radiological outcome. However skip laminectomy is relatively a easier procedure to perform, while the laminoplasty does need instrumentation.

Objective: To investigate the clinical outcomes, and the requirement of surgery following selective nerve root block performed for cervical radicular pain in patients with MRI proven disc pathology.

Methods: Thirty consecutive patients with cervical radiculopathy and correlating MRI pathology were studied. Mean age of patient was 46yrs (range 28–64yrs). Twenty nine of the thirty patients also complained of associated neck pain. All underwent fluoroscopically guided, selective cervical nerve root block with steroid (20mg Depomedrone) and local anaesthetic (0.5ml Bupivo-caine 0.25%). Radiographic contrast was used to confirm needle position. All procedures were conducted by the same clinician.

Pre and post procedure pain and physical function scores were noted using the standard SF 36 questionnaire, as well as whether subsequent surgery was required. Mean follow up time was seven months (range 2–13 months).

Results: 81% of patients reported an improvement in arm pain, and 66% in neck pain following the procedure. 77% of patients had an improvement in pain score (mean improvement 16 points). 68% of patients had an improvement in physical function score (mean improvement 20 points). At the time of follow up only one patient had undergone surgery for cervical radicular pain.

Conclusion: This study suggests that fluoroscopically guided selective nerve root block is a clinically effective interventional procedure in the management of cervical radicular pain, and may prevent the need for open surgery.

Introduction: We have assessed the clinical observation that the angle of the contralateral lamina matches the angle required from the sagittal plane for the placement of pedicle screws in the subaxial cervical spine.

Method: 54 axial CT scans were examined. All subjects were scanned for the exclusion of fracture between December 2003 and December 2004. The digitised images were analysed on the Philips PACS system using SECTRA software. 168 individual vertebrae were assessed between C3 and C7. The following were measured; the angle of the pedicle relative to the sagittal plane, the smallest internal and external diameter, the angle of the lamina and the distance from the lateral mass to the anterior vertebral body (LMAVB) in the line of the pedicle. Reproducibility was assessed in a subset of 10 individuals with paired measures using the FDA approved formula for CV%.

Results: Angular measures had a CV% of 3.9%. The re-measurement error for distance was 0.5mm. 336 pedicles were assessed in 25 females and 29 males. Average age was 48.2 years (range 17–85). Our morphologic data from live subjects was comparable to previous cadaveric data. Mean pedicle external diameter was 4.9mm at C3 and 6.6mm at C7. Females were marginally smaller than males. Left and right did not significantly differ. In no case was the pedicle narrower than 3.2mm. Mean pedicle angle was 130 deg at C3 and 140 deg at C7. The laminar angle correlated well at C3,4,5 (R2> 0.7) and was within 1 deg of pedicle angle. At C6,7 it was within 11 deg. In all cases a line parallel to the lamina provided a safe corridor of 3mm for a pedicle implant.

Conclusions: The contralateral lamina provides a reliable intraoperative guide to the angle from the sagittal plane for subaxial cervical pedicle instrumentation in adults.

Objective: To review the clinical outcome of 37 consecutive patients undergoing C1– C2 transarticular fixation for patients with Rheumatoid Arthritis.

Design: Prospective Observational Study.

Methods: There were 37 patients at 2 centres. Age range was 37– 82 years. The time since diagnosis to treatment was 2– 23 years. Clinical presentation included suboccipital pain in 26/ 37 patients and neck pain in 29/37 patients. 22 patients had presented with myelopathy ( Ranawat grade II or III A). The preoperative imaging included Plain X Rays, CT scans and MRI scans. All patients underwent C1/ C2 transarticular screws ( Stealth guided) except 4 patients in which an aberrant course of the vertebral artery was identified.

Outcome measures: Functional outcome, Complications, Postoperative Neurological Status, Neck Disability index, Myelopathy disability index.

Results: 1 patient had died at 12 month followup. Neck pain improved in 22( 75%) of patients by > 5 points on the VAS. Suboccipital pain had improved in all patients. 17 patients (80%) improved following operation on the Ranawat Grading, 2 patient were worse and 3 patients remained the same.

> 70% patients reported improvement in neck disability index and > 50% patients reported improvement in myelopathy disability index.

Conclusions: C1/ C2 Transarticular fixation with spinal navigation is a safe technique for treating atlantoaxial instability in patients with Rheumatoid Arthritis. This study demonstrates improvement in all domains including neck disability, myelopathy scores and functional outcome.

Introduction: There is growing interest in Health Related Quality of Life (HRQL) questionnaires to quantitate the impact of a variety of diseases and their treatments. The Short Form-36 (SF3) is a comprehensive measure of health status, consisting of 36 questions related to Physical (PCS) and Mental Component Summary (MCS).1 An abbreviated version of SF36, the SF12 has been described.2 We report on the use of SF12 and SF36 to assess the impact of surgery in patients with cervical spondylotic myelopathy (CSM).

Methods: In this prospective study, patients undergoing anterior or posterior decompressive surgery self completed the SF36 questionnaire pre-operatively and at 6 months post-operatively. The data from the SF36 is categorised into 8 scales: physical functioning (PF), physical role (PR), bodily pain (BP), general health (GH), vitality (VT), social functioning (SF), emotional role (ER) and mental health (MH).1 Each scale is scored on a 0 (maximum disability) to 100 (no disability) metric. These 8 scales are reduced to a Physical (PCS) and Mental Component Summary (MCS).1 SF12 utilises only 12 questions of the 8 scales of the SF36.2 We compared the validity, reliability and sensitivity to change in CSM patients.

Results: We studied 105 patients with a median age of 58. Post-operatively, there were improvements in the PCS components of both the SF36 (40 ± 2 to 54 ± 2) and SF12 (34 ± 2 to 48 ± 3) (p< 0.0001; Wilcoxon Signed Ranks test) and MCS component of SF36 (48 ± 2 to 63 ± 2) and SF12 (43 ± 2 to 59 ± 2) (p< 0.001). There were linear relationships between the SF36 and SF12.

Conclusions: Both the SF12 and SF36 scales are valid and sensitive to changes in CSM patients, undergoing decompressive surgery. Despite its abbreviated nature, SF12 appears to be an adequate substitute for SF36 and its brevity should increase its attractiveness to both the clinicians and patients.

Purpose: Published series of minimally invasive cervical foraminotomy (MICF) have shown excellent short-term relief of cervical radiculopathy (85–98%) with minimal surgical morbidity. There have been no long-term clinical series documenting the stability of these results over time. This is the first long-term follow-up of MICF patients to determine the incidence of recurrent symptoms and need for additional cervical spine surgery.

Methods: We conducted a multi-center retrospective chart review of 73 patients who had MICF. Clinical outcome measures were assessed from clinic records, operative records, and telephone surveys.

Results: At 3 months, 70/73 patients (96%) reported relief of radicular pain compared to their preoperative state. By 40 months, 15 patients reported symptoms of cervical radiculopathy. 8 patients experienced recurrent symptoms, and the remaining 7 had a new radicular pattern. Of 7 patients with symptoms at new levels, 6 had pre-existing radiographic abnormality. 15 patients underwent additional cervical surgery after MICF. 3 patients underwent repeat MICF at the same level. An additional 2 patients had MICF at a different level. 7 patients had ACDF at the same level and 2 had fusion at a different level. There were no cases of frank instability or spondylolisthesis noted.

Conclusions: At 40 month follow-up, 21% or patients had radicular symptoms with 11% reporting recurrence of preoperative symptoms and 9% with radicular symptoms in a different distribution. 12% (9/73 patients) of the group required ACDF within the follow-up period. Thus, 64/73 patients were spared fusion in this series. Assuming the 2.5% per year incidence of adjacent level fusion cited in the literature, there would have been 6 cases likely to have required another fusion if all 73 patients had been treated with ACDF initially. From this perspective, MICF continues to be our procedure of choice for properly selected patients with cervical radiculopathy.

There is an increasing awareness of the need to avoid of homologous blood transfusion in elective surgical practice. This stems from a better appreciation of the adverse effects of homologous blood transfusion and increasing pressure on blood stocks because of increasing restrictions on potential donors.

This study examines the effect of using modern blood conservation methods on the subgroup of our patients having surgery for adolescent idiopathic scoliosis. We chose this group because it is a homogenous group of patients of similar age, all of whom had major surgery of a similar severity, and in whom there were few contraindications to our blood conserving strategies.

We studied 78 consecutive patients with adolescent idiopathic scoliosis who underwent surgery. They were divided into two groups. Patients in the study group had one or more modern blood conservation measures used perioperatively. The patients in the comparison group did not have these measures.

There were 46 patients in the study group and 32 in the comparison group. Eight patients who had anterior only surgery, were excluded. The two groups did not differ in age, body weight, and number of levels fused or the type of surgery.

Only 2 patients in the study group were transfused with homologous blood and even these transfusions were off protocol. Wastage of the autologous predonated units was minimal (6/83 units predonated). In contrast all patients in the comparison group were transfused homologous blood. There was significant decrease (p = 0.005) in the estimated blood loss when all the blood conservation methods were employed in the study group.

Using blood conservation measures, lowering the hemoglobin trigger for transfusion and education of the entire team involved in the care of the patient can prevent the need for homologous blood transfusion in patients undergoing surgery for adolescent idiopathic scoliosis.

Purpose: We describe a technique using orthoganol imaging on a radiolucent table that allows reliable, safe and reproducible insertion of thoracic pedicle screws.

Method: The popularity of pedicle screws for spinal fixation in deformity surgery has increased. Studies have shown lumbar pedicle screws to be safe and effective. The biomechanical superiority of pedicle screws has also been demonstrated. Nonetheless, reluctance to apply the technique to thoracic vertebra remains, most likely because of perceived technical difficulties and a reported high complication rate.

We describe a technique using orthoganol imaging on a radiolucent table, used in a series of patients in whom we have inserted a total of over 2000 screws.

Results: We have inserted over 2000 thoracic pedicle screws without neurological injury. In addition, this technique has allowed us to use pedicle screw to the exclusion of other, less mechanically favourable, methods of fixation to the spine; over the same time period we used only three sublaminar hooks.

Furthermore, the lateral to medial or ‘toeing in’ of screw placement gives greater pull out strength to each screw by increasing the ‘volume’ of bone that has to be overcome before failure by pull out occurs. In addition this trangulation technique allows insertion of :screws of greater diameter than the pedicle and decreases the chance of broaching medially.

Conclusion: Using the technique described, we achieve accurate screw placement ‘first time, every time’, giving us a biomechanically superior construct, allowing more powerful derotation of the spine and thus greater correction of deformity. We recommend its use for all thoracic pedicle screws.

We describe results of a new ‘two needle technique’ of selective nerve root blocks done through posterior triangle of neck in the management of cervical radiculopathy with 2 year results.

Methods: Patients presenting with cervical radiculopathy were evaluated clinically and radiologically and were initially managed with supervised physiotherapy, analgesics and rest. Selective cervical nerve root block was offered to the patients, who did not respond to conservative management. The procedure was performed as a day case, under local anesthesia, with image intensifier guidance, using ‘two needle technique’. A thinner needle is rail-roaded through the lumen of large diameter guide needle to reach the target nerve root foramen and a mixture of Bupivacaine and Triamcinolone acetonide is injected. The outcome was measured using visual analogue score (VAS) and neck disability index (NDI) done on the day of the procedure and compared to the scores at 3 months and 1 year after the procedure.

Results: Outcome in 30 patients who underwent this procedure over three years’ period is presented. Average Visual Analogue Score was 7.36 (range 6 – 10) before the intervention, which improved to 2.27 (range 0 – 7) at 3 months and 1.9 (range 0 – 4) at 1 year. The average Neck Disability Index score prior to intervention was 66.87 (range 44 to 82), which improved to 31.67 (range 18 – 66) at 3 months and 30.44 (range 20 – 48) at 1 year. There were no major complications noted. We conclude that selective cervical nerve root block using ‘two-needle technique’ is safe and reproducible. The therapeutic effect achieved is long lasting, making this procedure a good alternative to surgical management in patients with cervical radiculopathy who do not respond to conservative management.

Aim: To compare thoracic scoliosis correction using either pedicle hooks or pedicle screws.

Methods and results: Two patient groups were studied. Data was collected prospectively and this is a review of the radiological data. All patients had structural thoracic scoliosis. Group 1, 14 patients (9 female and 5 male) mean age 14.6, were treated with posterior correction of scoliosis using the standard USS II technique using pedicle hooks and screws. Group 2, 14 patients (11 female and 3 male) mean age 15.3 were treated using pedicle screws alone to correct the apical deformity, using a variation of the original USS technique. Pre and postoperative Cobb angle, apical vertebral rotation (AVR, Perdriolle method) and apical vertebral translation (AVT) were measured.

Unpaired “t” test was used to compare the magnitude of correction in both groups. The mean follow up period was 6.7 months (range:3–18).

The mean corrections of Cobb angle, AVR and AVT, in group I were 61.1% (range:48.5–83.9), 33.3% (range:8.6–100) and 62.9% (range:43.2–91.4), respectively. In Group 2 the corrections were: 57.4% (range:21.4–81.7), 57.2% (range:16.7–100) and 58.7% (range:34–80.9).

There is no statistically significant difference between the correction of Cobb angle or AVT in both groups (P=0.479 and 0.443 respectively). However, the pedicle screws proved to be more effective at correcting the AVR (P= 0.017). No complications occurred and correction has been well maintained.

Conclusion: Pedicle screws can safely and effectively replace the pedicle hooks in the classical USS technique. They are more effective at correcting the rotational deformity, although do not provide a better correction of Cobb angle. These technical results now need to be correlated with relevant clinical outcomes.

Purpose: To identify patients in whom anterior scoliosis correction was not possible and to determine pre-operative factors that may predict such an outcome.

Methods: From 1999–2005, 257 patients were listed for anterior correction with the Kaneda Anterior Spine System (KASS). Of these 246 were completed successfully. However in 11 cases it was not possible to complete the procedure.

We performed a retrospective review of case notes and X-rays. A control group of 22 patients, in whom anterior surgery was completed, matched to age, sex and type of curve, was used.

Results: Two reasons for abandoning anterior instrumentation were identified; loss of cord signal (7) and failure to achieve adequate correction after anterior release and reduction (4).

Of the seven patients with lost signal three were syndromic and four were associated with syrinx. In all seven, loss of signal occurred on clamping of segmental vessels. All seven had no residual neurological deficit post-operatively and had uncomplicated posterior correction the following week.

All four patients in whom inadequate correction was achieved after anterior release and repositioning had idiopathic curves. Of these two were thoracic and two were thoracolumbar. Mean pre-operative Cobb angle was 67 (range 59–85) compared to a mean of 56 (range 42–68) in the control group. Mean pre-operative stiffness index was 91% (range 85%–100%) compared to a mean stiffness index of 65% (range 53–80) in the control population.

Conclusion: Whilst a successful outcome is achieved in a majority of KASS instrumentations we have identified two reasons why anterior surgery has to be abandoned. Whilst one often cannot pre-operatively anticipate intra-operative loss of cord signal, we found that in cases with an underlying syrinx there is a particular risk of this occurrence. Our experience has shown particularly stiff curves (Stiffness index ≥ 85%) may not be suitable for stand-alone anterior surgery.

Introduction: There has been controversy in recent publications for/against the value of intraoperative traction views under anaesthesia, both studies had patients with a mean standing cobb angle of 55o failing to show the predictive value of these views for curves greater than 60o.

Design: Compare predictive value of fulcrum bending views with intraoperative forced traction under anaesthesia (FTUGA) views in predicting curve flexibility; influencing the correction of curves greater than 60^o in scoliosis deformity.

Subjects: 35 patients with idiopathic scoliosis undergoing surgical correction; mean age was 19 yrs (9–40), the student’s t test and χ2 were used to assess the reliability of FTUGA views in predicting curve flexibility, degree of correction the fulcrum bending correction index (FBCI) used to measure curve flexibility and correction.

Results: The mean preoperative major curve standing and fulcrum bending views Cobb angle was 72^o (50–90), 59^o (20–82) respectively, and 37^o (14–54) on traction views. Posterior correction was performed in all patients. The mean postoperative major curve Cobb angle was 27 (10–54). The number of patients predicted for combined anterior release and posterior instrumentation was reduced from 22 to 3.

Predictive value for traction view according to standing Cobb angle was P=0.1 for Cobb angles (50–59), P=0.1 for Cobb angles (60–69), P= 0.01 for Cobb angle (70–79), P=0.01 for Cobb angle (80–90). P value for the difference between fulcrum bending views, traction views and post op correction P=0.001 in favour of traction views, the mean curve flexibility was 33%, 55% for fulcrum and traction respectively. Mean fulcrum bending and traction correction index were 232%, 123% respectively.

Conclusion: Forced Traction Under General Anaesthesia views were superior in predicting curve flexibility in curves that measured more than 70^o but weak predictor of final correction angle when performing posterior scoliosis correction.

We present in this study our experience in wide decompression, gradual acute reduction and fusion performed in a single sitting, for high grade spondylolisthesis in 17 adolescent cases.

Between 1994 and 2005 we undertook surgical management of 17 adoloscents with high dysplastic Spondy-lolisthesis. All our patients were young females except for one with average age of 13.9 years. All of our cases involved the lumbosacral junction. 8/14 cases presented with frank spondyloptosis (Grade5). Of the remaining 9 cases, 5/14 cases were grade4 and 4/14 were grade3 dysplastic spondylolisthesis respectively. Our indication for surgery in all these patients was unremitting back pain, radicular pain, abnormal posture, gait abnormalities and progressive slip. All these patients underwent single stage wide decompression, posterior instrumentation and reduction of the slips and postero lateral fusion. Since 1999 in addition to the above we routinely performed inter body fusion with cages in lumbosacral segment (9/17 cases).

All patients’ spondylolistheses were reduced to < grade2.16/17 of our patients had a very satisfactory outcome. Our average follow-up of these patients is 4 years (range 1–9 years).4/17 of our patients developed some dorsiflexion weakness postoperatively and all recovered within 3 months of operation.1 patient developed deep postoperative infection necessitating the removal of the implant.

We conclude that acute correction of high grade spondylolisthesis is a demanding procedure. The newer instrumentation (improved sacral fixation) made reduction less difficult and the final outcome is highly satisfying for the patient and the surgeon.

Study design: A retrospective review of patient records with recent clinical and radiographic assessment.

Objective: Long-term evaluation of the Luque trolley for posterior instrumentation in congenital scoliosis.

Summary of background data: From a group of 51 cases treated with the Luque trolley, we review 10 patients with progressive congenital scoliosis (5male, 5female) for a mean follow-up period of 14.8 years, to mean age of 19 years. The mean Cobb angle of the primary curve before surgery was 69.5 degrees. The mean Cobb angle of the secondary cervico-thoracic curve before surgery was 37.1 degrees and of the caudal secondary curve was 26.4 degrees. The mean age at surgery was 5.0 years. 8 patients had a selective epiphysiodesis procedure, 2 with hemi-vertebrectomy, and all underwent single- stage (7 patients) or dual-staged (3 patients) posterior instrumentation with a Luque trolley growing construct.

Method: Clinical evaluation and sequential measurements of Cobb angle were done, with recording of further surgical procedures, associated complications, and final coronal balance. The thoracolumbar longitudinal spinal growth (T1-S1) and growth in the instrumented segmented were also calculated.

Results: The mean preoperative primary curve Cobb angle of 69.5degrees, corrected to a mean postoperative angle of 30.6 degrees, with progression from here to curve magnitude of 38.8 degrees on latest follow up (approximate rate of progression of 0.55 degrees per year).

The mean pre-operative cephalic (cervico-thoracic) Cobb angle of 37.1degrees, corrected to 22 degrees, with progression to 26.6 degrees.

The mean pre-operative caudal (lumbar) Cobb angle of 26.4degrees, corrected to16.2 degrees, this later progressed to 20.6 degrees.

Coronal plane translation measured 1.68 cm at latest follow up [range 0.5–5.1cm].

The thoracolumbar longitudinal growth measured a mean of 8.81cm (approx0.8 cm/year) with a recorded lengthening of 2.54 cm (approx 0.23cm/year) in the instrumented segmented. Half the patients did not require further surgery.

Conclusion: Selective fusion does not always prevent further deformity in congenital scoliosis. The addition of posterior growing construct instrumentation did demonstrate capacity for good correction of primary and secondary curvatures and a limited capacity for further longitudinal growth.

Purpose: To evaluate the indications, outcome, risk factors and complications of transpedicular osteotomy (TPO) in revision scoliosis surgery

Methods: We evaluated patients undergoing TPO for revision scoliosis surgery at our institution between 1989 and 2004 with a minimum follow up of 18 months. Demographic data, anaesthetic risk factors, peri-operative data and complications were recorded. Radiographs pre-operatively, post-operatively and at last follow up recorded sagittal balance, coronal balance, lumbar lordosis and pelvic parameters. Functional outcome was measured using the Whitecloud score.

Results: 21 patients (24 TPO’s) mean age 48.7 years with mean follow up 4.4 years fulfilled criteria for study. All cases had fixed sagittal imbalance pre-operatively. Mean operative time was 4.6 hours and mean transfusion requirement was 2.3. units. A significant improvement (p< 0.03) in sagittal imbalance was gained (although in 3 cases of pseudarthroses this was partially lost) and the post-operative lumbar lordosis correlated closely significantly pelvic incidence (p< 0.03). Functional outcome was good/excellent in 67% cases.

We report 28 complications. 22 early included 4 dural tears, cardiac decompensation with reduction, 5 neurological deficits including a parpaplegia secondary to haematoma which was evacuated and the patient made a good recovery at 6 months, 2 UTIs, IVI infection, superficial wound infection and extension of metalwork due to early proximal decompensation. Late complications included infection (8 years), removal of prominent metalwork, radiculopathy due to screw (6 months) and 3 pseudarthroses. There was no statistically significant correlation of complication with weight, ASA grade or smoking.

Conclusion: TPO in revision scoliosis is an effective method of correcting both coronal and sagittal imbalance but is not without complication, although good functional outcome is achieved in most patients. It is important to consider pelvic parameters pre-operatively to plan the level and magnitude of TPO required.

Scoliosis and hip subluxation/dislocation are common and often coexistent problems encountered in patients with cerebral palsy (CP). The underlying mechanism may be related to muscle imbalance. Surgical correction may become necessary in severe symptomatic cases. The effect of surgical correction of one deformity on the other is not well understood.

We retrospectively reviewed a series of 17 patients with total body cerebral palsy with diagnoses of both scoliosis and hip subluxation who had undergone either surgical correction of their scoliosis (9 patients) or a hip reconstruction to correct hip deformity (8 patients). In all patients, the degree of progression of both deformities was measured, radiographically, using the Cobb angle for the spine and the percentage migration index for hip centre of rotation at intervals before and at least 18 months post surgery.

All patients who underwent scoliosis correction had a progressive increase in the percentage of hip migration at a rate greater than that prior to scoliosis surgery. Similarly, patients who underwent a hip reconstruction procedure demonstrated a more rapid increase in their spine Cobb angles post surgery.

There may be a relationship between hip subluxation/dislocation and scoliosis in CP patients. Surgery for either scoliosis or hip dysplasia may in the presence of both conditions lead to a significant and rapid worsening of the other. The possible negative implications on the overall functional outcome of the surgical procedure warrants careful consideration to both hip and the spine before and after surgical correction of either deformity. In selected cases there may be an indication for one procedure to follow soon after the other.

Introduction: Patient questionnaires permit a direct measure of the value of care as perceived by the recipient. The Scoliosis Research Society outcomes questionnaire (SRS-22) has been validated as a tool for self-assessment. We investigated the correlation between SRS-22 and a detailed radiological outcome two-years following anterior correction of ThoracoLumbar Adolescent Idiopathic Scoliosis (TL-AIS).

Methods: The SRS-22 questionnaire was completed by 30 patients two-years following anterior correction of TL-AIS. Pre-operative, post-operative and two-year follow-up radiographs of all 30 patients were assessed. The following parameters were measured at each time point: 1) Primary Cobb angle, 2) Secondary Cobb angle, 3) Coronal C7-midsacral plumb line, 4) Apical Vertebra Translation (AVT) of primary curve, 5) AVT of the secondary curve, 6) Upper instrumented vertebra (UIV) translation, 7) UIV tilt angle, 8) Lower instrumented vertebra (LIV), 8) LIV tilt angle 9) Apical Vertebra Rotation (AVR) of the primary curve, 10) Sagittal C7-posterior corner of sacrum plumb line 11) T5–T12 angle, 12) T12-S1 angle, 13) shoulder height difference. The percentage improvements for each were noted. Correlation was sought between Total SRS score, each of the five individual domains and various radiographic parameters listed above by quantifying Pearson’s Correlation Coefficient (r).

Results: Percentage improvement in primary Cobb angle (r = 0.052), secondary Cobb angle (r = 0.165) and AVT of the primary curve (r = −0.353) showed little or no correlation with the SRS-22 total score or any of its five domains. Significant inverse correlation was found between the UIV tilt angle at two years and the SRS-22 (r = −0.516). Lateral radiographs however showed little or no correlation between thoracic kyphosis (r = 0.043) and SRS-22.

Conclusion: The SRS-22 outcomes questionnaire does not correlate with most of the radiographic parameters commonly used by clinicians to assess patient outcome.

A 2002 study by Goldberg et al showed that surgery before age 10 for infantile onset idiopathic scoliosis (diagnosis < 4 years, Cobb angle => 10°) preserved neither respiratory function nor cosmesis, and has not been contradicted. In 2005, Mehta re-emphasised scoliosis correction by serial cast-bracing, while Thompson et al reported satisfactory results with growing rods. An analysis of the status quo of a cohort of patients with infantile idiopathic scoliosis (other diagnoses and syndromes excluded), managed by cast-bracing, was undertaken, asking whether interim progress was acceptable or demanded a change of protocol.

Of 35 patients born between October 1993 and December 2002,15 have completely resolved, age at diagnosis 1.6 ± 0.96 years, Cobb angle 20.3°±11.9, RVAD 11.1°±13.8, latest age 4.1± 2.3. 20 were prescribed cast-bracing, age at diagnosis 1.8±0.9 years, Cobb angle 47.3°±12.6, RVAD 29.6±24.5, age at treatment was 2.1±1.0 years. Cobb angle (p< 0.001) and RVAD (p=0.001) were larger in the treated group, but age at presentation was the same (p=0.473). Surgery was performed on 3 children unresponsive to initial casting, at ages 3.2, 3.6 and 3.7, and in 3 at ages 8.6, 10.1 and 11 years. 3 children, aged 6.0, 8.1 and 11.3 are out of brace with straight spines and 11 are stable in brace.

Infantile idiopathic scoliosis seems programmed to resolve or progress according to initial severity and in line with growth rate. Those who respond to casting in infancy generally remain stable until near puberty when surgery is uncontroversial. Those who progress relentlessly and immediately in cast remain the issue, as reports of newer methods include a wide range of ages and diagnoses and give their outcome in terms of Cobb angle only. It has not yet been shown that any treatment will alter their prognosis so constant analysis of all outcome parameters is essential.

Aim: This study measures the outcomes of surgery for neuromuscular scoliosis using patient/ carer goal setting techniques.

Method and Results: In neuromuscular scoliosis, the objective of surgery is to maintain or improve sitting ability and to improve overall function. Measuring the outcome of surgery by patient/carer grading of patient/ carer set goals has not been used in this patient group.

A group of 20 children who underwent spinal fusion for neuromuscular scoliosis were assessed using a postural and functional measure pre-op, post-op, and at 3 and 12 months post-op. In addition, each patient was asked to record three goals for undergoing the surgery. At one year post op, patient/carers were asked to grade on a scale of 0 – 10, how satisfied they were that the goals had been achieved.

Nineteen patients had clear pre-op goals for the surgery relating to functional activities. The most frequent goals stated for the non-ambulant children were- sitting for longer periods (7/46), making dressing easier (7/46) and sitting more upright (6/38). There were 15 other functional goals stated. The ambulant children stated- appearing straighter (3/12), increase in confidence (2/12), reducing pain (2/12) and maintaining respiratory function (2/12). There were 3 other functional goals stated. Seventeen patients completed the study, 2 were lost to follow up, 1 died. The average satisfaction rate from goals achieved 1 year post-op was 7.9/10.

Conclusion: Establishing goals that are realistic and contribute positively to the functional ability or practical management of the child with neuromuscular scoliosis undergoing spinal surgery, encourages the family to be central in the decision making process. It also allows unrealistic expectations to be discussed pre-op and represents the most patient centred method of outcome assessment.

Aim: The aim of this study is to prospectively evaluate the functional outcome of surgical correction in 20 patients with a significant neuromuscular scoliosis.

Method and Results: The principal objective of surgical correction of neuromuscular spinal deformity should be to maintain or improve function of the patient, but there is little evidence to support this. In wheelchair dependent patients the goal is also to maintain sitting ability, and in ambulant patients prevention of further deformity is important. Studies formally quantifying these outcome parameters have not been published with modern surgical techniques.

A consecutive series of 20 children with neuromuscu-lar scoliosis (age range 2–18 years) undergoing surgical correction were evaluated using 2 standard functional assessment tools, the Seated Postural Control Measure (SPCM) which assesses posture and function, and the Pediatric Evaluation of Disability Inventory (PEDI) which records functional ability in the domains of self-care, mobility and social function. The patients were evaluated pre-operatively and then at 2 weeks, 3 and 12 months post-operatively.

Complete data is presented for all patients at 3 months and 13 of 20 patients at 1 year follow up, the remaining data is to be collected.

The SPCM demonstrated an improvement in posture in 95% from pre-op to 2 weeks post-op, with 25% demonstrating some regression at 3 months. Most maintained or improved this at 1 year. The PEDI demonstrated a reduction in mobility at 3 months but at 1 year 60% returned to preop status.

Conclusion: Sitting position is improved by surgery, but mobility is impaired for a significant period following the correction, which may have more impact on the child’s and families life. Families need to be counselled prior to surgery about the loss of mobility and ability to self-care post operatively but that it does return by one year.

Purpose: To investigate the potential value of titanium anterior interbody cages compared to morselized rib graft for anterior interbody fusion in combination with posterior instrumentation, correction and fusion for Scheuermann’s kyphosis.

Methods and Materials: A Non-Randomised historic cohort study of two surgical techniques in matched subjects was carried out.15 patients with identical pre-operative radiographic and physical variables (age, gender, height, weight, BMI ) were managed with combined anterior release, interbody fusion, posterior instrumentation, correction and fusion . Group A (n=8) had morsilized rib graft inserted into each intervertebral disc space. Group B (n=7) had titanium interbody cages packed with bone graft inserted at each level. The posterior instrumentation extended from T2 to L2 in both groups. Pre- and post-operative curve morphometry was studied on plain radiographs by two independent observers. The indices studied included Cobb angle, Ferguson’s angle(FA) , Voutsinas index(VI), Sagittal Vertical Axis (SVA), Sacral Inclination (SI) and Lumbar Lordosis (LL). Interbody Fusion was assessed at final follow up. Each patient was reviewed at 3, 6, 12, 24, 48 and 60 months following surgery with standing radiographs. Wilcoxon-matched pairs test and Mann-Whit-ney test were used for statistical analysis.

Results: The average follow-up for groups A was 70 and Group B,66 months. For the whole group, the pre-operative : postoperative median Cobb angle, FA, VI, SVA and SI were 86: 42degrees, 50 : 28.4degrees, 28.7 :13, −3.5 : −4.0 centimetres and 40 : 34 degrees respectively. There were significant differences for all variables [p< 0.01] indicating good correction. At four-year follow-up, fusion criteria were satisfied in 12 / 15 cases (80%). Three patients had distal junctional kyphosis. There was no significant difference with respect to the variables between the two groups and both retained the post-operative correction achieved.

Conclusion: There was no significant advantage in the use of anterior titanium interbody cages over the use of morselized rib graft in the surgical management of Scheuermann’s Kyphosis.

The purpose of the study is to assess changes in cortical activity in chronic low back pain patients with and without illness behaviour.

Introduction: It is well recognised that patients with chronic low back pain (CLBP) may have major psychological factors which affect their level of disability. Abnormal patterns of illness behaviour have been described ¹.

Methodology: 30 patients with CLBP of more than six months duration were recruited. Patients with radicular pain or previous surgery were excluded. Two groups were created dependant on the presence of Waddell signs. “Copers” (n=16) showed 0 or 1 Waddell signs. “Non-copers” (n=14) showed 4 or 5 Waddell signs.

After informed consent, all subjects underwent fMRI scanning. Experimental pain was induced by thermal stimulation of the right hand. Straight leg raising (SLR) was performed following visual clues indicating that a leg raise was either definitely, possibly or not going to occur. Finally, clinical LBP was simulated by direct vibrotactile stimulation of the lumbar spine to a VAS threshold of 7/10.

The individual fMRI scans were independently referenced to anatomical markers and corrected for motion. Inter group analysis was performed using cluster-corrected thresholds of p< 0.05.

Results: During experimental pain stimulation, Non-copers showed significantly increased cortical activity as compared to Copers. Similar findings were evident when SLR was anticipated. The areas of increased cortical activity were primarily regions known to be involved in affective pain interpretation suggesting heightened activity.

When clinical LBP was simulated, the outcome was strikingly different with the Copers showing increased cortical activity particularly in the dorsolateral prefron-tal cortex and regions associated with cognitive pain processing and inhibition of subcortical pain pathways.

Discussion: This study shows that in patients with CLBP and illness behaviour cortical pain processing is abnormal. The findings suggest that possibly the abnormal behaviour shown by such patients may be due to failure of cognitive inhibitory pain pathways. It is possible that these abnormalities might respond to either pharmacological or psychological treatment.

Aim: The purpose of this study was to evaluate the extent of neurological deficit following excision of spinal neurofibromas.

Methods: Retrospective case series, combined with contemporary neurological examination and outcome questionnaires.

Results: 46 patients (26 males, 20 females) with a mean age of 46 between the years of 1985 – 2005. The incidence of neurological deficit subsequent to nerve sectioning to remove the tumour was 28/46 (60.9%) in the acute period. In the long term this reduced to 28%.

Conclusions: Despite the sectioning of nerves during surgery motor or sensory deficit was surprisingly rare. It was mainly sensory and recovered with time. This is presumably due to neural plasticity and dermatomal overlap. These results provide useful information for surgeons to counsel their patients preoperatively.

The purpose of this study is to determine whether the mode of anaesthesia chosen for patients undergoing lumbar microdiscectomy surgery has any significant influence on the immediate outcome in terms of safety, efficacy or patient satisfaction.

This prospective randomised study compared safety, efficacy and satisfaction levels in patients having spinal versus general anaesthesia for single level lumbar micro-discectomy.

Fifty consecutive healthy and cooperative patients were recruited and prospectively randomised into two equal groups; half the patients received a spinal anaesthetic (SA), the remainder a general anaesthetic (GA). Each specific mode of anaesthesia was standardised.

Comprehensive postoperative evaluation concentrated on documenting any complications specific to the particular mode of anaesthesia, recording the pace at which the various milestones of physiological and functional recovery were reached, and the level of patient satisfaction with the type of anaesthesia used.

The results showed no serious complication specific to their particular mode of anaesthesia in either group. Thirteen out of 25 SA patients required temporary urinary catheterisation (9 males, 4 females) while among the GA group 4 patients required urinary catheterisation (4 males and 1 female). Post-operative pain perception was significantly lower in the SA group. The SA patients achieved the milestones of physiological and functional recovery more rapidly. While both groups were satisfied with their procedure, the level of satisfaction was significantly higher in the SA group.

In conclusion, lumbar spinal microdiscectomy can be carried out with equal safety, employing either spinal or general anaesthesia. While they require more temporary urinary catheterisation associated with the previous use of intrathecal morphine, patients undergoing SA suffer less pain in association with their procedure and recover more rapidly. Blinded to an extent by not having experienced the alternative, both groups appeared satisfied with their anaesthetic. However, the level of satisfaction was significantly higher in the SA group.

Aim: To determine the need for caudal epidural steroid injections to be administered with a mixture containing local anaesthetic.

Patients: 100 consecutive patients listed for caudal epidural by two spinal orthopaedic consultants with lum-bosacral radiculopathic pain. 19 patients did not fulfil the criteria for the trial.

Methods: Subjects randomised to either steroid injection (80mg triamcinolone) with 18mls 0.25% bupivicaine or steroid injection with 18mls Normal saline. Pre-injection maximal (Pmax) and average (Pav) pain scores and Oswestry Disability Index (ODI) scores were obtained for each patient. Pain scores were repeated at 48 hours, 2 weeks and 8 weeks with a second ODI.

Results: A significant improvement in both Pav and Pmax were seen over the study period for both groups. There was no significant difference in either group for ΔPav. or ΔPmax at any stage of the study. Those patients who received a mixture containing bupivicaine underwent a significant improvement in their ODI in contrast to those who were injected with the saline mixture. There was also a significant difference in the ΔODI between groups.

Conclusion: Epidural bupivicaine injection appears to enhance the effect of epidural steroid injection with adequate levels of monitoring and access to specialist support. There may be a beneficial effect on the local pain pathways by the local anaeasthetic that outlasts the direct pharmacolgical effect.

Purpose: To assess the effectiveness of nasal salmon cal-citonin in the treatment of lumbar spinal stenosis

Methods: Forty patients with symptoms of neurogenic claudication and MRI proven lumbar spinal stenosis were enrolled into the study. They were randomly assigned to either nasal salmon calcitonin 200 i.u or placebo nasal spray (sodium chloride) for the first 4 weeks. At the end of the 4 weeks of initial treatment the patients were given a 6 weeks washout period, during which they received no further nasal spray and were instructed to continue with their normal analgesics. At the end of this period all patients received a further 6 weeks of active nasal salmon calcitonin.

Outcome measures: Oswestry Disability Index (ODI), Low Back Outcome Score (LBOS), Visual Analogue Score (VAS) for leg and back pain, Shuttle Walking Test Distance in metres.

Results: In the 4 weeks during which patients received active/placebo nasal salmon calcitonin there was no statistically significant difference in the change in outcome scores between the two groups (change in ODI [p=0.51], change in VAS for leg pain [p=0.51] and change in shuttle walking distance [p=0.78]) There is a minimal improvement in the mean ODI at the end of only 3.7 points in the calcitonin group and 3.8 points in the placebo group [p=0.44]. The VAS for leg pain deteriorated in both groups. There was a minimal improvement in the VAS for back pain in the calcitonin group of 5 mm, it deteriorated in the placebo group by 11mm [p=0.03]. At the end of the trial 9 patients (23%) reported either an excellent or good outcome, 6 reported a fair outcome (15%) and 17 patients (43%) reported a poor outcome.

Conclusion: This dose of Nasal salmon calcitonin is not effective in the treatment of patients with lumbar spinal stenosis.

Purpose: To measure outcome in patients undergoing decompression for lumbar canal stenosis (LCS) by lami-nectomy.

Methods: 100 patients (57 men, 43 women) under one consultant surgeon presenting with neurogenic claudication and MRI confirmed LCS were studied . 23 patients had pre –existing spondylolisthesis (21 Grade 1, 2 Grade-2) and were managed by laminectomy without fixation. Patients completed a set of outcome measure questionnaires (SF-36, Visual analogue scores for back pain, leg pain, leg sensory symptoms and the Roland-Morris back disability score) pre-operatively, 3 months post surgery and at longer term follow up (median 2 years). Outcome scores were analysed and for SF-36 compared to age matched normative data. Statistical significance was calculated using Wilcoxon’s matched pairs and correlations using Spearman’s rank test. Statistical analysis was performed using the SPSS statistical package.

Results: Average age 68 years (inter-quartile range 60 – 77). For the cohort visual analogue scores and Roland scores showed significant improvement (p < 0.01) at both 3 months and at long term follow up compared to pre-operative scores. For the physical functioning domain of SF-36, outcome scores improved significantly (p< 0.01) at short and long term follow up with 80% of patients having better long term scores compared to pre-operative scores. The physical functioning domain of SF-36 was significantly correlated with the changes seen in the visual analogue pain scores and the Roland back pain score (p < 0.01). Outcome for the spondylo-listhesis subgroup was similar to the outcome in patients without pre existing spondylolisthesis.

Conclusions: Laminectomy for lumbar canal stenosis is an effective treatment resulting in significant health gains which are maintained in the longer term. Our data validates SF-36 as a measurement of disease severity and outcome in this condition.

Purpose: To evaluate the long term clinical outcomes as well as radiological changes in distal unfused mobile segments and to evaluate factors that may predispose to distal disc degeneration and/or poor outcome.

Method: 151 mobile segments in 85 patients (65 female), mean age 43.2 (range 21–68), were studied. Curve type, number of fused levels and pelvic incidence were recorded. Clinical outcome was measured using the Whitecloud function scale and disc degeneration using the UCLA disc degeneration score. Spinal balance, local segmental angulations and lumbar lordosis were measured pre- and post-operatively as well as at the most recent follow up – mean 9.3 years (range 7–19).

Results: 62% of patients had a good or excellent outcome. 11 had a poor outcome of which 10 underwent extension of fusion – 5 for pain alone, 3 pain with stenosis and 2 pseudarthroses. Pre-operative disc degeneration was often asymmetric and was slightly greater in older patients. Overall, there was a significant deterioration in disc degeneration (p< 0.0001) that did not correlate with clinical outcome. Disc degeneration correlated with the recent sagittal balance (Anova F=14.285, p< 0.001) and the most recent lordosis (Anova F=4.057, p=0.048). The post-operative sagittal balance and local L5-S1 sagittal angulation correlated to L4 and L5 degeneration respectively. There was no correlation between degeneration and age, pre-operative degenerative score, pelvic incidence, sacral slope, number of fused levels or distal level of fusion.

Conclusion: Disc degeneration does occur below an arthrodesis for scoliosis in adults which does not correlate with clinical outcome. The correlation of loss of sagittal balance with disc degeneration may be as a result of degeneration causing the loss of balance or vice versa i.e. sagittal imbalance causing degeneration. Immediate post-operative imbalance correlates with degeneration of the L4/5 disc, which may imply the latter.

Purpose: Inadequate disc fragment excision, suboptimal bony decompression of the lateral recess, and persistent foraminal and far lateral compressive lesions are the most common cited causes for persistent radiculopathy after lumbar decompressive surgery. This study examines the utility of continous intraoperative monitoring of electromyographic (EMG) nerve root potentials during decompression of lumbar radiculopathy using a proprietary neurophysiological EMG monitoring system (Neurovision; Nuvasive; San Diego, CA).

Methods: A prospective, non-blinded, non-randomized study was undertaken in 43 patients with symptomatic lumbar radiculopathy and weakness undergoing decompressive surgery. All had previously failed conservative therapy. Preoperative and postoperative data for neurological strength examination, EMG amplitudes, VAS scores for radiculopathy were recorded. Continuous EMG nerve root potentials were monitored and recorded during surgery.

Results: At the time of surgery, 39 of 43 patients demonstrated measurable asymmetric EMG amplitudes. Of these 39, 30 patients had clinical strength improvements. Intraoperative EMG improvements were seen in 21 of these 30 patients with an overall sensitivity of 70%. Of 9 patients who did not improve in strength, 8 demonstrated no improvement or worsening on EMG for a specificity of 89%. Overall, EMG nerve root monitoring had a positive predictive value of 95.5% and a negative predictive value of 47.1% with regards to strength improvement. 3 cases had worsened transient weakness that resolved within 3 months. In detecting such injury, EMG was 100% sensitive, 97% specific with a positive predictive value of 75% and a negative predictive value of 98%.

Conclusions: Use of intraoperative EMG nerve root surveillance may provide a useful adjunct in determining the adequacy of decompression during surgery of compressive lumbar radiculopathy and may help to predict the degree of motor improvement. Although a rare complication, EMG is particularly sensitive at detecting iatrogenic injury to the nerve root during surgery.

Objective: This was to analyse RLBUHT orthopaedic spinal service’s provision of spinal care and to determine the impact on the need for surgery.

Methods: This was a three-year retrospective cohort study of orthopaedic patients with spinal related problems from January 2003 to January 2006. The sample included all patients referred to the service by general practitioners in Liverpool. Patients were examined by orthopaedic musculoskeletal physiotherapists lead by senior specialist therapists. The latter had autonomy to access imaging investigations and blood tests. Patients were referred to the consultant surgeons for surgical consideration when appropriate or to the physiotherapy department for non-surgical management. Outcome measures used included the Stockport Scale, the Roland and Morris Disability Questionnaire, the Neck Disability Index, the Euroquol Questionnaire and the Visual Analogue Scale.

Results: 17,214 patients were referred to the service from January 2003 to January 2006. 9,896 patients attended, 2,600 failed to attend and 4,718 cancelled their appointments. The number of referrals increased from 4,499 in 2003 to 5,695 in 2004, and 7,020 in 2005. Patients going on for surgery remained 200 to 220 cases per annum. The waiting times to surgery decreased from 3 to 6 months, to within 3 months. An audit of 300 patients discharged from the physiotherapy department using the Stockport Scale from January 2005 to January 2006 revealed that problems were solved / goals achieved in 40.3% of patients, with significant improvement in 42.7%, some improvement in 8.3% and no improvement or no data in 8.7%.

Conclusion: Over the three-year period there has been a significant increase in the number of patients managed by this service. This has not resulted in an increase in patient waiting-time. Surgical intervention per head of population has not altered and has been sooner. Our experience demonstrates an effective model of care for large urban populations.

Aim: To assess the kinematic changes that occur within the lumbar spine 2 years following insertion of the Dynesys Spinal stabilisation implant.

Materials and Methods: Twenty patients who were treated with Dynesys surgical stabilisation for dominant lower back pain underwent positional MRI scanning before and two years following surgery.

The patients were divided into two groups, A and B. The first, Group A, in which only Dynesys was used and the second, Group B, in which Dynesys was used adjacent to one or more fused segments.

Results: The results of the pMRI measurements showed that the range of movement (ROM) of the L1/S1 angle in Group A reduced by 11.8o{pre-op=37.9o, postop=26.1o(p=0.085)} while in Group-B reduced by 12.3o {pre-op=37.8o, postop=25.5o(p=0.017)}.

The ROM of the end plate angle at the instrumented segments in Group A reduced from 5.72^o to 1.44^o{difference 4.28^o(p=0.005)} and in Group B reduced from 6.00^o to 2.17^o,{difference 3.83^o(p=0.001)}.

The ROM of the end plate angle at the level above instrumentation in Group A reduced from 8.2^o to 5.1^o {reduction 3.1^o(p=0.085)}, while in group-B increased from 7.3^o to 7.5^o, a difference of 0.2^o (p=0.877).

The mean anterior disc height in Group A reduced by 2.1mm (p< 0.001) from 9.59mm to 7.44mm. The posterior disc height also reduced from 6.56mm to 6.26mm, a difference of 0.3mm, (p=0.434). In Group B, the anterior disc height reduced by 1.98mm (pre-op=9.04mm, post-op= 7.06mm, p=0.001) and the posterior height by 0.35mm (pre-op 6.14mm to post op 5.79mm, p=0.443)

Discussion: This study shows that the Dynesys stabilisation system allows some movement at the operated segment two years following surgery. The study also confirms that the adjacent segment hypermobility often seen following spinal fusion surgery is eliminated.

Purpose: To establish the results of a three week functional restoration program in terms of commonly used surgical outcome measures

Method: 135 patients ( 57 male 78 female) undertook a three week functional restoration program consisting of hydrotherapy, gymnasium work, education and cognitive behavioral therapy. They completed pre-program standard questionnaires including the Oswestry Disability Index and the Roland Morris. Follow up was at an average of 26 months (std dev 7) The patient global assessment of worse, unchanged, better and much better were completed as well as the pre-program outcome measures.

Results: Oswestry; Roland Morris

Pre program 34 average: s.d. 158.8; s.d. 4.5

Post program 19 average: s.d. 174.3; s.d. 4.8

Patient Global assessment:

Much better 64; 47%

Excellent 62; 49.6%

Better: 52; 38%

Good: 43; 34.4%

Unchanged: 2; 9%

Fair: 16 ; 2.8%

Worse: 7; 5%

Poor: 4; 3.2%

Data on the impact upon work was available for 121 of the patients. Pre program 71 of the 121 had been seriously affected in the workplace. Work follow up was 79% and at follow up only 22 out of 96 were seriously affected in the workplace. A significant improvement.

43 had an injury at work, RTA or similar significant event, 89 did not. The ODI improved by 18 points in the attributable event group and 13 in the non event group. Similar results were found for the Roland score. There was no significant difference between the two groups.

Conclusion: A very favourable results in the treatment of chronic back pain can be achieved, despite including adverse patient groups. Over 80% of patients were in the ‘success’ treatment groups at follow up using the Scandinavian Spine stabilization study group global assessment tool. Surgeons, patients and health care purchasers need to be aware of what can occur with non surgical treatment.

Aim: The clinical and radiological outcomes of a prospective randomised controlled trial comparing Femoral Ring Allografts (FRA) to Titanium Cages (TC) for circumferential fusion are presented.

Methods: Eighty-three patients were recruited fulfilling strict entry requirements (> 6 months chronic discogenic Low Back Pain (LBP), failure of conservative treatment, one or two level discographically-proven discogenic pain). Five patients were excluded on technical infringements (unable to insert TC or FRA). From 78 patients randomised, 37 received FRA and 41 received TC. Posterior stabilisation was achieved with translaminar or pedicle screws. Patients completed the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) for back and leg pain, the Short-Form 36 (SF-36) pre-operatively and 6, 12 and 24 months post-operatively. Assessment of fusion was made by a panel of 6 individuals examining radiographs taken at the same specified time points.

Results: Clinical outcomes were available for all 83 patients (mean follow-up 28 months, range 24–75). Baseline demographic data showed no statistical difference between groups (p< 0.05). For patients receiving FRA, mean VAS (back pain) improved 2.0 points (p< 0.01), mean ODI improved 15 points (p=< 0.01), and mean SF-36 scores improved by > 11 points in 6 of 8 domains (p< 0.03). For patients receiving TC, mean VAS improved 1.1 points (p=0.004), mean ODI improved 6 points (p=0.01), and SF-36 improved significantly in only two of eight domains. Revision procedures and complications were similar in both groups. For the FRA group, 27 levels were fused from a total of 42 assessed (64.2%). For the TC group, 33 levels were fused from a total of 55 assessed (60%). This difference was not statistically significant p> 0.2.

Conclusion: The use of FRA in circumferential lumbar fusion was associated with superior clinical outcomes when compared to those observed following the use of TC. Both groups had similar fusion rates.

Introduction: This study investigates the effect of soma-tisation on results of lumbar surgery.

Methods: Pre- and postoperative data of all primary discectomies and posterior lumbar decompressions was prospectively collected. Pain using the Visual Analogue Score (VAS) and disability using the Oswestry Disability Index (ODI) were measured. Psychological assessment used the Distress Risk Assessment Method (DRAM). Follow-up was at 1 year.

Results: There were a total of 320 patients (average age 49.7 years). Preoperatively there were 61 Somatising and 75 psychologically Normal patients. 47 of the pre-operative Somatisers were available for follow-up.

All pre-operative parameters were significantly higher compared with the Normal group (back pain VAS 6.3 and 3.8; leg pain VAS 7 and 4.7; ODI 61 and 34.4 respectively).

At 1 year follow-up, 23% of the somatising patients became psychologically Normal; 36% became At Risk; 11% became Distressed Depressed; and 30% remained Distressed Somatisers.

The postoperative VAS for back and leg pain of the 11 patients who had become psychologically Normal was 3.4 (pre-op 6.8) and 3.2 (pre-op 6.6) respectively. In the 14 patients who remained Distressed Somatisers the corresponding figures were 5.6 (pre-op 7.8) and 6.7 (pre-op 7.0).

The postoperative ODI of the 11 patients who had become psychologically Normal was 26.4 (pre-op 55.5).

In the 14 patients who remained Distressed Somatisers the corresponding figures were 56.7 (pre-op 61.7).

These differences are statistically significant.

Discussion: Patients with features of somatisation are severely functionally impaired preoperatively. One year following lumbar spine surgery, 60%(28) had improved psychologically, 23%(11) were defined as psychologically normal. This was associated with a significant improvement in function and back and leg pain. The 14(30%) patients who did not improve psychologically and remained somatisers had a poor functional outcome. Our results demonstrate that psychological distress is not an absolute contraindication to lumbar spinal decompressive surgery.

Purposes: To evaluate the effectiveness of Posterior Lumbar Interbody Fusion (PLIF) surgery in resolving back and back related leg pain and its effect on quality of life.

Methods: Two hundred and twenty six patients who met the inclusion criteria of degenerative disc disease, spondylolisthesis, disc herniation and postlaminec-tomy/postdiscectomy syndrome unresolved by conservative therapy were entered into the study. Patients were assessed using a self-administered questionnaire containing the Oswestry disability index (ODI) for back pain related disability, visual analogue scales (VAS) for back and leg pain severity (0 = none, 10 = worst imaginable pain) and the SF-36 general health questionnaire. Outcomes were assessed preoperatively and at a minimum of 2 years follow-up. Statistical significance was tested using a paired t-test after confirming normality of the data.

Results: Of the 226 patients,182 (99 females, 83 males; mean age at treatment, 45.3 years; age range 15 – 67 years) returned follow-up questionnaires (81% response). The mean duration of follow-up was 26.4 months (range 24 – 60 months). The ODI showed a statistically and clinically significant improvement between baseline (52.1) and follow-up (29.5), (22.6(17.8 to 27.5); P= 0.000). This represents a 43% improvement in functional ability. There was a statistically and clinically significant improvement between VAS back pain scores at baseline (7.7) and follow-up (3.9), (3.8 (3.1 to 4.4); P = 0.000 ). This represents a reduction of 49%. Similarly VAS leg pain at baseline (6.6) and follow-up (3.2) ,(3.4 (2.7 to 4.2); P = 0.000) showed a reduction of 52% which was also statistically and clinically significant. All dimensions of the SF-36 except role physical showed a statistically and clinically significant improvement.

Conclusion: The results show that in our series, there is a statistically and clinically significant improvement in pain, functional ability and quality of life after PLIF surgery in patients with chronic back and leg pain unresolved by conservative therapy.

We report a consecutive series of 200 patients who underwent Dynesys flexible stabilisation in the management of intractable lower back pain.

Methods: Patients were only accepted for the study if exhaustive conservative management had failed. They underwent operation between September 2000 and March 2003. Patients were divided into two groups:

Group 1 - Cases where implantation was used as an adjunct to other procedures including decompression, discectomy, or posterior lumbar interbody fusion. (32 male, 36 female, Mean age 56years (range 31–85)).

Group 2 - Patients with back pain and/or sciatica in which no other procedure was used. (65 male 67 female, Mean age 58years (range 27–86))

All patients were profiled prospectively using the Oswestry Disability Index (ODI), SF36 and Visual Analogue Scale (VAS). Patients were reviewed post-operatively using the same measures at 3, 6 & 12 months, and yearly thereafter. Follow-up was 95% at 2 to 5 years.

Results: Group 1 – Mean ODI fell from 54 pre-op to 24 at four years

Group 2 – Mean ODI fell from 49 pre-op to 28 at four years

Similar trends were observed in both groups with a fall in VAS and improvement in SF36.

Discussion: Indications can only be defined following clinical outcome. Perceived indications were based on contemporary understanding of the biomechanical effects of the construct. Further investigation of these variables is clearly desirable. Screw failures (15%) have detracted from the overall success. The virtue of flexible stabilisation over fusion includes avoidance of domino effect, reversibility and possible healing of a painful segment. The key issue is whether it is as effective and this requires prospective randomised controlled investigation, both against fusion, and conservative management. We feel our results in this difficult group of patients are reasonable and continue to use it in our practice.

Purposes: To evaluate the effectiveness of Posterior Lumbar Interbody Fusion (PLIF) surgery in resolving back and back related leg pain and its effect on quality of life.

Methods: Two hundred and twenty six patients who met the inclusion criteria of degenerative disc disease, spondylolisthesis, disc herniation and postlaminec-tomy/postdiscectomy syndrome unresolved by conservative therapy were entered into the study. Patients were assessed using a self-administered questionnaire containing the Oswestry disability index (ODI) for back pain related disability, visual analogue scales (VAS) for back and leg pain severity (0 = none, 10 = worst imaginable pain) and the SF-36 general health questionnaire. Outcomes were assessed preoperatively and at a minimum of 2 years follow-up. Statistical significance was tested using a paired t-test after confirming normality of the data.

Results: Of the 226 patients,182 (99 females, 83 males; mean age at treatment, 45.3 years; age range 15 – 67 years) returned follow-up questionnaires (81% response). The mean duration of follow-up was 26.4 months (range 24 – 60 months). The ODI showed a statistically and clinically significant improvement between baseline (52.1) and follow-up (29.5), (22.6(17.8 to 27.5); P= 0.000). This represents a 43% improvement in functional ability. There was a statistically and clinically significant improvement between VAS back pain scores at baseline (7.7) and follow-up (3.9), (3.8 (3.1 to 4.4); P = 0.000 ). This represents a reduction of 49%. Similarly VAS leg pain at baseline (6.6) and follow-up (3.2) ,(3.4 (2.7 to 4.2); P = 0.000) showed a reduction of 52% which was also statistically and clinically significant. All dimensions of the SF-36 except role physical showed a statistically and clinically significant improvement.

Conclusion: The results show that in our series, there is a statistically and clinically significant improvement in pain, functional ability and quality of life after PLIF surgery in patients with chronic back and leg pain unresolved by conservative therapy.

Purpose: To evaluate the changes in lumbar spine kinematics and clinical outcomes of patients with spinal stenosis 2 years after implantation of the X Stop interspinous decompression device.

Methods: 10 patients (6 males; 4 females) underwent X Stop procedure. Age ranged from 57 years to 71 years. 15 levels were operated (5 single levels: L_2-3 - 1, L_4-5 - 4; 5 double levels: L_3-4 +L_4-5 – 4; L_4-5+L₅S₁ – 1). A 0.6 Tesla Upright MRI scanner was used to acquire images in seated (flexion, extension, and neutral) and erect postures at preoperative, 6 months, and 2 years after surgery. The total range of motion of the lumbar spine and the operated segments were measured, along with changes in disc height, areas of the exit foramens, and dural sac. Clinical outcomes were assessed by Zurich Claudication Questionnaire before and 3, 6, 12, and 24 months after surgery.

Results: Mean Zurich Claudication Scores (n=10)

At 6 months, there was a significant increase in the spinal canal and foraminal dimension. However at 2 years there was a reduction in these dimensions such that there was no significant difference from the preop-erative measurements.

Conclusion: The results of this prospective observational study indicate that X Stop offers significant short-term improvement. It is a safe, effective, and less invasive alternative for treatment of lumbar spinal stenosis. The maximum clinical benefit and mechanical efficacy seems to be realized in the early stages postoperatively with gradual reduction thereafter over 2 years. Co-existing co-morbidities such as obesity and osteoarthritis in the lower limbs may influence the clinical results.

Aim: To assess the kinematic changes that occur within the lumbar spine 2 years following insertion of the Dynesys Spinal stabilisation implant.

Materials and Methods: Twenty patients who were treated with Dynesys surgical stabilisation for dominant lower back pain underwent positional MRI scanning before and two years following surgery.

The patients were divided into two groups, A and B. The first, Group A, in which only Dynesys was used and the second, Group B, in which Dynesys was used adjacent to one or more fused segments.

Results: The results of the pMRI measurements showed that the range of movement (ROM) of the L1/S1 angle in Group A reduced by 11.8o{pre-op=37.9o, postop=26.1o(p=0.085)} while in Group-B reduced by 12.3o {pre-op=37.8o, postop=25.5o(p=0.017)}.

The ROM of the end plate angle at the instrumented segments in Group A reduced from 5.72^o to 1.44^o{difference 4.28^o(p=0.005)} and in Group B reduced from 6.00^o to 2.17^o,{difference 3.83^o(p=0.001)}.

The ROM of the end plate angle at the level above instrumentation in Group A reduced from 8.2^o to 5.1^o {reduction 3.1^o(p=0.085)}, while in group-B increased from 7.3^o to 7.5^o, a difference of 0.2^o (p=0.877).

The mean anterior disc height in Group A reduced by 2.1mm (p< 0.001) from 9.59mm to 7.44mm. The posterior disc height also reduced from 6.56mm to 6.26mm, a difference of 0.3mm, (p=0.434). In Group B, the anterior disc height reduced by 1.98mm (pre-op=9.04mm, post-op= 7.06mm, p=0.001) and the posterior height by 0.35mm (pre-op 6.14mm to post op 5.79mm, p=0.443)

Discussion: This study shows that the Dynesys stabilisation system allows some movement at the operated segment two years following surgery. The study also confirms that the adjacent segment hypermobility often seen following spinal fusion surgery is eliminated.

Background: The recent significant surge in disc arthroplasty surgery has popularised the minimally invasive anterior approach to access the target disc. However, as the abdomen and its great vessels are not the natural territory for the spinal or neurosurgeon, extra care must be taken to access the disc whilst still minimising the risk of the not too uncommon vascular injury. Three dimensional CT angiography has been routinely used in this centre as part of pre operative planning of disc surgery. This was prompted by the frequent intraoperative observation that the vascular pattern has often been far from consistent.

Aim of Study: To assess the anatomic variations of the major abdominal vessels.

Methods: The pre operative 3D CT angiograms of eighty nine patients who had lumbar disc replacements were examined studying specific vascular anatomic parameters.

Parameters studied included position of the Aorta and Inferior Vena Cava, the levels and angles of their bifurcation and the all too important ascending lumbar vein. We also commented on the most accessible (visible) disc part in relation to surrounding vessels.

Results: We found significant variations in vessels anatomy in all parameters studied, confirming inconsistency of the abdominal vasculature. In particular, the angio-grams suggested an alternative approach to access the L4/5 disc in 30% of cases.

Discussion: The incidence of vascular complications in disc arthroplasty surgery is reported to be around 3%. This includes laceration particularly to the left common iliac vein, thrombosis, both arterial and venous and intimal tears. Most of these complications are more than often the result of excessive traction and failure to adequately visualise and mobilise the vessels. Pre operative imaging is therefore critical to plan best vascular approach to the disc. Although MRI scanning is useful in assessing the vasculature, it is less superior to 3D CT angiograms in delineating vessels topographic relation to vertebra and disc.

Conclusion: We have noticed significant variations in abdominal vasculature anatomy. This may have a direct influence on access to L4/5 and higher discs in a siginificant number of cases.

The purpose of the study was, to investigate how often the diagnosis of “Scheuermann’s disease” was made in radiological reports to General Practitioners, to determine the precise nature of the disease being described, and to evaluate the management of patients by GP’s who receive such radiological reports.

A computerised search of radiological reports to local GP’s revealed fifty reports over a two and a half period which included the diagnosis of “Scheuermann’s disease”. Assessment of these radiographs by a Consultant Radiologist indicated that ten of these patients had classical Scheuermann’s (abnormal thoracic kyphosis associated with disc and end plate irregularities), and forty had so called lumbar/type two Scheuermann’s (disc and end plate irregularities of the thoraco lumbar spine without deformity).

A questionnaire was sent out to GP’s which consisted a case history of a middle aged patient with typical symptoms of degenerative low back pain without deformity, including a radiological report indicating the “possibility of Scheuermann’s disease”, on the basis of features typical of Scheuermann’s lumbar/type two.

86% of GP’s indicated that they would inform their patients that they had “Scheuermann’s disease” using that term, but 48% did not appreciate the meaning of the term in the context of the case history.

We conclude that the majority of radiological reports to GP’s which include the diagnosis “Scheuermann’s disease” relate to lumbar/type two Scheuermann’s, and that the nature of the radiological diagnosis, invariably passed on to the patient, is often misunderstood by the GP. This may well result in patients presenting to spinal clinicians with unnecessary anxiety due to concerns of possible serious pathology.

We would recommend that spinal clinicians encourage their radiological colleagues to avoid the use of the words “Scheuermann’s disease” in radiological reports to GP’s except when describing classical adolescent thoracic kyphosis.

We investigated the effect of neck dimension upon cervical range of movement. Data relating to 100 subjects healthy subjects aged between 20 and 40yrs was recorded with respect to age, gender and ranges of movement in three planes. Additionally two commonly used methods of measuring neck motion, chin-sternal distance and uniplanar goniometer, were assessed against a validated measurement tool the CROM goniometer (Performance Attainment Associates, Roseville, MN).

Using multiple linear regression analysis it was determined that sagittal flexion (P= 0.0021) and lateral rotation (P< 0.0001) were most closely related to neck circumference alone whereas lateral flexion (P< 0.0001) was most closely related to a ratio of circumference and length. The uniplanar goniometer has some usefulness when assessing neck motion, comparing favourably to chin-sternal distance that has almost no role.

Neck dimension should be incorporated into cervical functional assessment. One should be wary about recorded values for neck motion from non-validated measurement tools.

Objective: To assess the effectiveness of total disc replacement (TDR) (Charité SB III) for treatment of lumbar discopathy and to report the preliminary clinical results after a minimum follow-up period of two years

Materials and Methods: From 49 patients who underwent lumbar TDR, 31 patients fulfilled the criteria for clinical evaluation at least 2 years after surgery. The mean age was 39ys (range 29 – 48). Preoperative diagnosis included degenerative disc disease in 27 patients and 4 patients had post discectomy back pain. 44 disc prosthesis were implanted, 18 patients had a single level disc replacement and 13 patients had two level replacement. All patients were studied prospectively and clinical results evaluated by assessing preoperative and postoperative Oswestry Disability Index questionnaire and Visual Analogue Scale for back pain. Pre and postoperative patients’ work status as well as patient satisfaction were also assessed. The mean postoperative follow up was 3.3years (range 2 – 8 years). Statistical analysis of the results was done with the Wilcoxon Signed Ranks Test.

Results: There were significant improvements of the clinical outcome measures. Mean post operative ODI compared to mean preoperative scores of 19 and 53 respectively (p< 0.0001) and mean postoperative VAS compared to mean preoperative scores of 2.5 and 7.5 respectively (p< 0.0001). Success rates showed 51.6% of patients had an excellent result (relative improvement of ODI score, > 75%), 19.4% had a good result (relative improvement of ODI score, 60% to74%), and 29% had a fair and poor results (relative improvement of ODI score, < 60%). No major or approach related complications were encountered.

Conclusions: TDR is an effective method of treating discopathic low back pain. The medium term results are comparable to those obtained following traditional lumbar arthrodesis. Yet longer term results are still needed to comment on adjacent segment load transfer and progression of degenerative changes.

Neuromuscular scoliosis is a difficult condition to treat. Curve severity, secondary pelvic obliquity and poor respiratory function can make operative treatment and post operative care challenging. The benefits to the child in terms of improved sitting position and trunk posture can be considerable. We present a large consecutive series of patients with neuromuscular scoliosis treated surgically at our institution.

The aim of this work was to study the clinical and radiographic impact of surgery for neuromuscular scoliosis.

Data was gathered from patient records and radiographs for all cases of neuromuscular scoliosis treated surgically between April 2002 and Feb 2005. 52 cases were identified. They fell into 2 surgical groups: single stage posterior correction and two stage anterior and posterior correction. All posterior instrumentation was transpedicular. Complications, length of stay, and change in severity of sagittal and coronal plane deformity were recorded.

Average pre-operative Cobb angle was 85°. There were 16 patients with additional sagittal plane deformity. Average percentage improvement of Cobb angle was 59%. The correction was better in two stage procedures. Pelvic obliquity was improved in those who were obligatory sitters. Fusion rate was 83% for those followed up more than 1 year. ITU stay was longer in single stage procedures. Complication rate was 58%.

We have shown that with appropriate patient selection the correction of neuromuscular scoliosis can achieve good results with high fusion rates. Two stage correction confers correctional advantage on those who have sufficient respiratory reserve to tolerate it.

The current work compares, in the patients with acute spinal cord injuries (SCI), the rate of early complications in those who were operated ‘out of hours’ to the patients who had their surgical interventions performed on the elective trauma list.

In a two-year study, all the complications occurring within the first month of surgery were recorded. Patients who had their operative procedure between 22.00 pm and 8.00 am comprised the ‘out of hours’ group, while the other group included patients operated on daytime spinal trauma lists. Each group had 22 patients. The demographics, injury patterns, time relapse to admission and theatre, the surgical procedure, its duration, the postoperative results and early complications were retrospectively analysed and compared for the two groups.

There were 38 males. 20 patients had complete SCI and 26 had thoracic spine involvement. Road traffic accident was the cause of injury in 26 patients. Two patients received steroids following the injury. The average admission time was 3 days. Surgery occurred on an average within 48 h (range 1–20 days). The mean theatre time was 2.8 h for the emergency group and 3.4 h for the elective cases. Early postoperative complications were chest infections (5), urinary tract infections (7), superficial wound infections (2), and pulmonary embolism (1). The incidence of complications was higher in cervical injuries, polytrauma, complicated procedures and individuals requiring intensive care. No significant differences were noted between the two groups.

Operating non life-saving emergency cases on elective list constitutes good clinical practice. Various reviews including the National Confidential Enquiry into Patient Outcomes and Deaths (NCEPOD) suggest that operating out of working hours poses a substantial risk to the patient’s health and safety. This study emphasizes that complications relate to the injury level, associated injuries and the procedure itself, rather than to the timing of surgery.

Introduction: Cervical spine pedicle morphology has been assessed by direct measurement and by CT in cadavers. We have assessed reproducibility and produced data for normal ranges in live subjects from the UK.

Method: 54 axial CT scans were examined. All subjects were scanned for the exclusion of fracture between December 2003 and December 2004. The digitised images were analysed on the Philips PACS system using SECTRA software. 168 individual vertebrae were assessed between C3 and C7. The following were measured; the angle of the pedicle relative to the sagittal plane, the smallest internal and external diameter, the angle of the lamina and the distance from the lateral mass to the anterior vertebral body (LMAVB) in the line of the pedicle. Reproducibility was assessed in a subset of 10 individuals with paired measures using the FDA approved formula for CV%.

Results: Angular measures had a CV% of 3.9%. The re-measurement error for distance was 0.5mm. 338 pedicles were assessed in 25 females and 29 males. Average age was 48.2 years (range 17–85). Our data from live subjects was comparable to previous cadaveric data. Mean pedicle external diameter was 4.9mm at C3 and 6.6mm at C7. Females were marginally smaller than males. Left and right did not significantly differ. Mean LMAVB was 34mm (min 21mm). In no case was the pedicle narrower than 3.2mm. Mean pedicle angle was 130 deg at C3 and 140 deg at C7.

Conclusions: CT measurement has acceptable reproducibility. Previous cadaveric measurements have been validated in live subjects in the UK. Although there is some variation in morphology, instrumentation no wider than 3.0mm and no longer than 20mm is unlikely to prove too large for an adult pedicle.

Purpose: To compare two different techniques of inter-body fusion in treatment for single level degenerative spondylolisthesis with symptomatic spinal stenosis.

Methods: Retrospective review of patients with degenerative spondylolisthesis and spinal stenosis treated with decompression and instrumented posterior interbody fusion with and without cages. Between 1996 and 2003 there were 59 patients with single level degenerative spondylolisthesis and spinal stenosis. Of these 32 were treated with complete laminectomy, interbody grafting and pedicle screw fixation. In the second group of 27 patients, the technique was modified by the incorporation of an interbody cage in an attempt to improve the restoration of lordosis. Both groups were comparable in terms of pathology, age, sex, intraoperative technique and were treated by the same surgeon. All patients were followed up at 6, 12, 26 and 52 weeks with radiographs and were assessed for fusion and maintenance of lordosis at a minimum of 1 year.

Results: There was a statistically significant difference between pre and postoperative lordotic angles in both groups. There was no significant difference in clinical outcomes between the two groups, nor was there a statistical difference in postoperative lordotic angles at the end of 1 year between the two groups. We had 2 deep infections in the cage group. There was one implant failure in the no cage group.

Conclusion: We did not find any advantage in using interbody cages in treating single level degenerative spondylolisthesis.

The clinical and radiological outcome of 34 patients who were treated with PDN-Solo and PDN-Solo XL devices for symptomatic degenerative lumbar discs is described.

34 patients had PDNs implanted in their lumbar spines between September 2002 and August 2004. Suitable patients, with proven discogenic back pain, who failed at least six months of conservative treatment, were fully consented prior to surgery. The approach was retroperitoneal in all cases except at L5/S1 when it was transperitoneal. The primary clinical outcome measure was the Low Back Outcome Score (LBOS). X-rays were taken at these follow-up points to assess the integrity and effectiveness of the implants.

36 operations were performed in 15 males and 19 females (including 2 early revision PDNs). All patients were between 20 and 65 years old, with a mean age of 42. 17 patients were treated with PDN alone and 17 with PDN as an adjunct to an interbody fusion.

There were 10 device related complications, two being amenable to early PDN revision and six requiring revision to fusion. Two patients remain symptom-free.

According to the LBOS, only 19 of 29 patients who have not been revised to fusion have had successful outcomes (65.5% of unrevised patients, 56% of all patients). Final follow-up x-rays show that when the PDN remains intact the disc space height is very similar to its neighbours. If the device has dissociated, the disc is narrowed.

Fifty years after lumbar disc nucleus replacement was first attempted by Fernstrom, the success rate is no higher and the reasons for revision are the same. Clearly there has to be a major improvement in this technology before it can be widely adopted. Until such a time as that improvement has occurred, we cannot recommend this device as a treatment for back pain.

Purpose: To perform a genome scan for suitable UK multiplex families and identify new genetic loci for AIS.

Method: DNA samples from 208 subjects (134 affected, 17 reduced penetrance members and 79 normal) from 25 multi-generation British families with confirmed diagnosis of AIS were selected from our AIS family database, and genotyped for 410 polymorphic markers from the entire genome, spaced at 10 cM intervals. Genotypic data were exported into Cyrillic to construct the most likely inherited haplotypes for each chromosome and in each family. Two–point LOD scores were calculated using MLINK initially for the entire genotypic data, and again for the affected meioses only, followed by GENEHUNTER for multipoint linkage analysis for each family.

Results: Overall, 170,560 genotypes were obtained and analysed. DNA samples from 250 subjects from the 25 families are currently available for further genotyping and saturation mapping. Preliminary inspection of inherited haplotypes indicates that a number of these families may be segregating with several new AIS loci with LOD scores ranging from 1.0 – 3.6 for various DNA markers on 15 different chromosomes (1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 13, 16, 17, 20, 21), and absence of linkage to the X chromosome. Linkage evaluation and comprehensive saturation mapping of the 2 loci with the highest LOD scores were conducted and these regions were successfully refined. Candidate genes are currently being screened.

Conclusion: Preliminary evidence already indicates genetic heterogeneity of AIS. Candidate genes from the two highest LOD score loci are at present being screened.

Background: Clinical trials of surgery increasingly use disability and quality of life scales as their primary outcome measures. As such, they are the central dependent variables on which treatment decisions are based. It is therefore essential that these scales provide clinically meaningful and scientifically sound (reliable and valid) measurements.

Aim: The aim of this study was to determine if three scales used widely for spinal surgery (the Short form 36 item health survey – SF-36, Oswestry and Neck Disability Indices – ODI, NDI) satisfied basic requirements for reliable and valid measurement, and if they were suitable to detect clinically significant change.

Method: We analysed data from 147 people undergoing cervical (SF-36, NDI), and 233 people undergoing lumbar (SF-36, ODI) spine surgery. We tested the full range of measurement properties of these scales. These included the assumption that adding up items generates meaningful scores and, if that test was passed, scale targeting to study samples, reliability, validity and responsiveness.

Results: In both samples, the SF-36 had problems. Some scales had notable floor and ceiling effects. As a consequence they were unable to detect change. Other scales failed validity tests. Importantly, there was no support for using SF-36 summary scores in either cervical or lumbar surgery. With the ODI and NDI, there were problems with the individual questions. Specifically, the item response options were not working as anticipated. This compromises the reliability and validity of both scales.

Conclusions: This study, whose aim was to assess three scales used to evaluate surgery, not the surgery itself, demonstrates that all three have important limitations and questions their suitability for this crucial role. Essentially, all three scales give inaccurate estimates of treatment effectiveness. The result is that the benefits of spinal surgery are almost certainly being under-evaluated and spinal surgeons are selling themselves short.

Study purpose: Cancer patients presenting with symptomatic spinal metastases is an increasing problem. It is widely accepted that surgery plays an important role in the management of these patients and recent studies1 conclude that surgical treatment should be more frequently offered. However, who should be offered surgery remains controversial, largely because of a lack of information about outcome. Our study is a prospective analysis of survival and functional outcome in patients with metastatic spinal disease treated primarily by surgical decompression and stabilisation when indicated.

Methods: Sixty two patients with radiologically suspected metastatic spinal disease, managed by one consultant neurosurgeon, were enrolled into a prospective cohort study. Patients presented with pain and or myelopathy. Survival, continence, walking, analogue pain scores and short form 36 (SF-36) scores were analysed.

Results: Median age was 62 years (22–79 years, 35 female, 27 male) with the commonest primary tumours being breast (26%), lymphoma (13%) and prostate (10%). Lung cancer was poorly represented (1 patient). Survival rates were 56% at 1 year, 49% at 2 years and 28% at 3 years. Of 16 patients not walking pre-op, 8 gained the ability to walk, while 5 out of 7 incontinent patients gained continence following surgery.

Conclusion: Our data indicate that long term survival and favourable functional outcomes can be achieved following surgery in patients with metastatic spinal disease. We strongly advocate that patients presenting with metastatic spinal disease be considered for primary surgical treatment but would highlight the importance of appropriate patient selection.

Background: Guidelines for the management of Low Back Pain (LBP) consistently recommend that initial assessment should focus on the detection of serious spinal pathologies. In 1994 the UK Clinical Standards Advisory Group introduced the concept of “red flags”. One flag is the presentation of back pain in people under the age of 20. LBP in children is common, with an annual and lifetime prevalence of around 30%. Because many cases of benign and malignant spinal tumours and spinal infection have been documented in this age group, young people with LBP who are referred to secondary care are investigated by MRI.

Purpose: The purpose of this study is to review the incidence of tumour and infection in subjects under age 20, who present to secondary care with LBP, but do not have concerning objective findings such as neurology, fever, acute deformity or scoliosis.

Method/Results: A retrospective analysis of the MRI database, at a specialist orthopaedic hospital, from 1994 until 2005 identified 403 limited MRI’s taken in LBP patients under the age of 20. Analysis revealed 2 radiological reports of spinal tumour, 1 ependymoma and 1 osteoid osteoma and no cases of spinal infection. Histology confirmed pathology in the ependymoma but excluded serious pathology in the osteoid oste-oma. Other MRI findings, included minor degenerative change (17%), pars defect (9%) and disc prolapse (4%). Therefore, over an 11 year period only 0.25% of young people with LBP who underwent limited MRI were found to have serious pathology.

Conclusion: In conclusion, LBP is relatively common in people under the age of 20 and can be severe enough to warrant secondary care referral. However, in the absence of other objective findings, serious pathologies such as cancer and infection remain rare. These results support the use of limited MRI for screening. However, further research into the clinical value of “under 20” as an independent red flag is recommended.

Recent work has demonstrated that intra-operative contamination of spinal surgical wounds is relatively common. The most frequently isolated wound contaminants are Propionibacterium spp. and coagulase negative Staphylococcus spp. The aim of this study is to examine the efficacy of prophylactic antibiotics used for spinal surgery against bacterial contaminants isolated from intra-operative samples retrieved during spinal surgical procedures.

Intra-operative wound samples were taken from 94 patients undergoing spinal surgery. Samples including skin, subcutaneous tissue and wound washings were processed, inoculated onto agar and incubated under both aerobic and anaerobic conditions for a period of 2 weeks. Bacterial growth was identified using commercially available biochemical test galleries. Thirty-six bacterial isolates were identified. The predominant bacteria isolated included Propionibacterium spp. (n=21) and coagulase negative Staphylococcus spp. (n=15). Each bacterial isolate was tested for its susceptibility to antibiotics used as antimicrobial prophylaxis during spinal surgery. Antibiotic sensitivities were determined in accordance with National Committee for Clinical Laboratory Standards (NCCLS) guidelines.

The antibiotic that performed best against Staphylococcus spp. isolated was ciprofloxacin with 93% of isolates being susceptible to this antibiotic. Cefamandole and cefuroxime also performed well against Staphylococcus spp. isolates.

The antibiotic that performed best against Propioni-bacterium spp. isolates was cefamandole with 100% of isolates being susceptible. Cefuroxime and ciprofloxacin also performed well. The antibiotic that performed least well against bacterial isolates was erythromycin with only 76% of Propionibacterium spp. and 47% of Staphylococcus spp. exhibiting susceptibility.

The results of this study demonstrate that ciprofloxacin, cefuroxime and cefamandole are effective against the majority of Propionibacterium spp. and Staphylococcus spp. isolated from within the spinal wound during surgery. The use of erythromycin in the penicillin allergic patient is questioned and ciprofloxacin proposed as a possible alternative.

Aim: A meta-analysis of randomised controlled trials was performed to investigate the effectiveness of surgical fusion for chronic low back pain compared to non-surgical intervention.

Methods: Several electronic databases (MEDLINE, EMBASE, CINAHL and Science Citation Index) were searched from 1966 to October 2005. Two authors independently extracted data. The meta-analysis comparison was based on mean difference in Oswestry disability index (ODI) change from baseline to follow up of patients undergoing surgical versus non-surgical treatment.

Results: Four studies of 58 articles identified in the search were eligible with a total of 740 patients. One of the studies recruited patients with adult isthmic spondylolisthesis, whereas the other studies recruited patients with a history of chronic low back pain of at least 1 year duration. Surgical treatment involved pos-terolateral fusion with or without instrumentation and flexible stabilisation. Non-surgical treatment involved exercise programs with or without cognitive therapy. The follow-up period ranged from 1 to 2 years. The mean overall difference in ODI between the surgical and non-surgical groups was statistically in favour of surgery (mean difference of ODI: 3.90; 95% confidence interval: 0.17–7.62; p=0.04; I²=21.4%). Surgical treatment was associated with a 13% pooled rate of early complications (95% confidence interval: 6–20%).

Conclusion: Surgical fusion for chronic low back pain favoured an improvement in the ODI compared to non-surgical intervention; this difference in ODI is of minimal clinical importance. Furthermore, surgery is associated with a significant risk of complications. Therefore, the cumulative evidence at present does not support routine surgical fusion for the treatment of chronic low back pain.

Purpose: To study acute effects of Intradiscal Electrothermal Therapy(IDET) on biomechanical properties of human intervertebral discs using Scanning Acoustic Microscopy(SAM) and 11.6 Tesla Nuclear Magnetic Resonance(μNMR)Microscope.

Materials and Methods: Five SpineCATH® IDET catheters (Smith& Nephew) were sited in the lumbar discs of a fresh frozen human cadaver under image control. 6 regions of interest (ROI) – anterior middle (AM), right anterolateral (RAL), left anterolateral(LAL), posterior middle(PM), right posterolateral (RPL) and left postero-lateral (LPL) were marked. These ROI were then subjected to SAM (50MHz, Kremer GmbH).

SAM was performed in C-scan mode(gate width 50ns, depth 3500ns) and acoustical data collected along X–Y plane/depth Z. A B- mode scan acquired acoustic data along X–Z plane/ depth A. Time-of-Flight (TOF) scan used to create 3D-like images based on distance between the top of the disc and maximum penetration depth.

The IDET catheters were heated according to the 90⁰C 16.5-minute protocol. Discs were subjected to SAM using identical protocols as described. The ROIs were incised and analysed using μNMR. A custom made device was fabricated to prevent rotational effects of varying orientation of the specimen in the magnetic field.

Results: 30 ROI were studied using SAM and μNMR. Acoustic Impedance was significantly decreased (p< 0.01)on SAM and these changes were confined only to LPL and LAL.

Non-linear regression analysis of Signal Intensity Ratios of 30 different regions using SPSS showed a significant change in T1 weighting on μMRI by a median factor of 40 ( IQR + 16) for the LPL and 20(IQR + 8) for LAL regions. Significant relaxation difference (p< 0.001) caused by “magic angle”effects wer noted in LPL compared to RPL.

Conclusion: This is the first study depicting structure of human intervertebral discs using 11.6T μMRI and SAM and exploring its clinical potential. The study irrefutably proves that IDET decreases stiffness coefficient only in the treated area. The findings on SAm closely mimicked findings on μMRI.

Introduction: Following the publication of our original survey in 2000 (Eur. Sp. J.11(6):515–8 2002) we have sought to re-evaluate the perceptions and attitudes towards spinal surgery of the current UK orthopaedic Specialist Registrars (SpR’s), and to identify factors influencing an interest in spinal surgery. At that time 175 orthopaedic spinal surgeons in the UK needed to increase by 25% to satisfy parity with other European countries.

Methods: A postal questionnaire was sent to all 950 SpR’s. The questionnaire sought to identify perceptions in spinal surgery, levels of current training and practice, and intentions to pursue a career in spinal surgery.

Results: As before, a 70% response rate has confirmed that 74% of trainees intend to avoid spinal surgery (69% in 2000). However 10% are committed to become a Specialist Spinal Surgeon (9% in 2000). Their perceptions were wide ranging but most concluded that the intellectual challenge and opportunities for research are widely recognised. However enthusiasm is dampened by poor perceptions of outcomes from surgery, negative somatization and depression associations, complications and the fear of litigation. In some areas there is inadequate exposure to spinal surgery during the first 4 years of training.

Conclusions: Spinal surgery remains a career choice for 10% of surgical trainees (up 1% since 2000). With a large SpR expansion (578 to 950 SpRs in the last 5 years) an average of 16 new spinal surgeons annually will be produced over the next six years. This has improved on the figure of 8.6 per year from 2000 and represents a 200% increase in numbers per year. These figures suggest that by 2011 and allowing for retirement, there should be enough spinal surgeons to meet the desired UK/Europe ratio.

Aim: To measure the quality of five major scientific meetings by assessing the publication rate of papers presented and recording their citation index.

Material and Methods: Abstracts of podium presentations at the meetings of the Scoliosis Research Society, International Society for the Study of the Lumbar Spine, British Scoliosis Society, BritSpine and Eurospine were included. We performed a Medline search to identify publications from the abstract. We calculated the time from meeting to publication and recorded the citation rate of the articles.

Results: Of 396 abstracts, 182 were published in peer-review journals – a publication rate of 46%. The publication rates of the five meetings (SRS, BSS, ISSLS, Eurospine, Britspine) were 69%, 53%, 51%, 38%, 24% respectively. Most publications were in “Spine” (55%), then European Spine Journal (11%). The median citation rate of the papers from the SRS, ISSLS, BSS, Eurospine, Britspine meetings was 3, 3, 3, 2, and 1 respectively. The average time to publication was 16 months.

Discussion & Conclusions: Podium presentation is a valuable means for the dissemination of research findings. However, a paper in a peer-reviewed journal is subjected to greater scrutiny, and is perhaps a better indicator of the work’s merit.

The average rate of publication in medicine following presentation is 45%¹. Spinal meetings are within this range.

Although the quality of the scientific work is not the only factor to determine publication, and nor is the quality of the presentations the only factor to assess in evaluating a meeting, the rate of publication and citation rate provide an indicator of the quality and scientific level of meetings.

Purpose of study: This study assessed the current availability of “out of hours” MRI scans for patients who present with symptoms suggestive of cauda equina syndrome to trauma units across the United Kingdom (UK).

Methods: 98 trauma units in 212 hospitals across the UK were identified. Senior house officers and registrars were questioned about the availability of emergency MRI scans after 5pm and midnight and at weekends. All units responded to the survey.

Results: 88 of 98 units had an on-site MRI scanner. In 32 hospitals, an MRI scan could be obtained after 5pm. In only 27 hospitals was this possible after midnight. In 58 units (65%) of cases, consultant to consultant contact was required to arrange the scan. 67 units found it “very difficult” or “impossible” to obtain an MRI scan at the weekend producing a potential delay of 64 hours from presentation at 5pm on a Friday night to 9am on a Monday morning.

Conclusions: The availability of urgent MRI scans in cases of suspected cauda equina syndrome currently represents a “postcode lottery” across the UK. This may mean that patients requiring urgent surgical decompression face a significant delay in diagnosis. Delayed or missed cases of cauda equina syndrome have huge personal, social and economic impact. On-site MRI facilities, which are available 24 hours a day for such cases are recommended in all units receiving an acute trauma on call.

Introduction: Sacroiliac joint pathology can contribute to lowback pain and sciatica. Its frequency and significance is controversial.

Aims: The purpose of this study is to evaluate the incidence and clinical significance of positive SI joint pathology on MRI scans.

Methodology: 353 MRI reports and scans carried out over a one year period for backpain and sciatica were reviewed. Demographic data and clinical notes of patients who had positive SI joint pathology on MRI scans were analysed. Correlation between clinical suspicion of SI joint pathology and MRI findings was studied.

Results: 12 scans showed pathology in the SI joint, an overall incidence of 3.3%.8(66%) were males and 4(33%) females. Only 4(33%) of these patients had Plain Film abnormality. Average age of 41.2 years (33–54). One patient was known case of Ankylosing Spondylitis. Other positive pathology included oedema, sclerois and bridging osteophytes. Clinicians requested inclusion of SI joint in 43 patients. 8 of these were positive, an incidence of 18.6%. In 130 patients, the SI joints were imaged as routine. This yielded positive pathology in 4 patients (3%).

Conclusion: Our study concludes that 18.6% of patients who are suspected to have SI joint involvement clinically have positive pathology on MRI scans.

Routine inclusion of imaging of the SI joint as part of lumbosacral spine MRI for back pain and sciatica shows only 3% positive results.

SI joint should be imaged only if clinically suspected.

Objectives: Ex vivo biomechanical study to compare the properties of isolated, fractured, vertebral bodies after treatment by kyphoplasty with one of two bone tamps: a balloon bone tamp (Kyphon®) or an expandable polymer bone tamp (SKyBone®).

Methods: Simulated compression fractures were created in 21 vertebral bodies (L3–5) harvested from red deer (sp. elaphus. elaphus), with initial strength and stiffness determined concurrently. Deer spine was selected as an alternative to human cadaveric spine due to its availability and its very similar bone density and morphological profile. Vertebral bodies were assigned to one of three groups: (1) unaugmented (control); (2) kyphoplasty using a balloon bone tamp (BBT); and (3) kyphoplasty using a polymer bone tamp (PBT). The kyphoplasty treatment consisted of deploying the bone tamp biped-icularly, then filling the created voids with standardised low viscosity cement. All vertebrae were then recom-pressed to determine their augmented strength and stiffness. Data was analysed using one-way analysis of variance test and paired samples T-Test.

Result: Following fracture and subsequent kyphoplasty augmentation, the median strength of the BBT group was 6.71kN (± 2.71) vs 7.36kN (± 3.43) in the PBT group. Median stiffness in the balloon bone tamp group was 1.885 kN/mm (± 0.340) compared with 1.882 kN/ mm (± 0.868). Augmented strength tended to be greater in the PBT group than for BBT group, but this difference was not significantly different (p> .8). Significantly greater strength was obtained after kyphoplasty using BBT or PBT, compared with control group (p=.001 and .04, respectively). BBT and PBT groups were not statistically different for augmented stiffness (p=.4). Both BBT and PBT groups have greater augmented stiffness as compared to the control group (p=.007 and .005, respectively).

Conclusions: The use of a polymer bone tamp creates similar augmented vertebral body strength and stiffness as compared with the widely used balloon bone tamp in a deer spine model. Similar results would be expected in human spine and consequently the polymer bone tamp may be used as an alternative bone tamp for kyphoplasty.

Introduction: Restoration of vertebral height for burst fractures can be achieved either anteriorly, posteriorly or combined.

Aim: To biomechanically assess and compare stiffness of 1) posterior pedicle screws with Synex, 2) Synex+ Double screw+rod Ventrofix 3) Synex+ Double screw+ Single rod and 4) Synex+ Single screw+ Single rod in reconstructing an unstable burst fracture following anterior corpectomy.

Method: Fresh frozen calf lumbar spines (L3–L5) were dissected and L4 corpectomy performed. L3 and L5 were mounted on a plate and fixed. Loads were applied as a dead weight of 2Nm. The range of movement was measured using the Qualisys motion analysis system using external marker clusters attached to L3 and L5. Bony landmarks were identified with marker clusters as baseline. The movement was measured between the 2 marker clusters.