Massive posterosuperior cuff tears (mRCT) retracted to the glenoid are surgically challenging and often associated with high retear rates. Primary repair is a less-favourable option and other salvage procedures such as SCR and tendon transfers are used. This study presents clinical and radiological outcomes of muscle advancement technique for repair of mRCT. Sixty-one patients (mean age 57±6, 77% males and 23% females) (66 shoulders) underwent all-arthroscopic rotator cuff repair that included supraspinatus and infraspinatus subperiosteal dissection off scapular bony fossae, lateral advancement of tendon laminae, and tension-free double-layer Lasso Loop repair to footprint. Pre-and post-operative range of motion (ROM), cuff strength, VAS, Constant, ASES, and UCLA scores were assessed. Radiologic assessment included modified Patte and Goutallier classifications. All patients had MRI at 6 months to evaluate healing and integrity of repair was assessed using Sugaya classification with Sugaya 4 and 5 considered retears. Advanced fatty degeneration (Goutallier 3-4) was present in 44% and 20% of supraspinatus and infraspinatus. Tendon retraction was to the level of or medial to glenoid in 22%, and just lateral in 66%. 50.8% mRCT extended to teres minor. Subscapularis was partially torn (Lafosse 1-3) in 46% and completely torn (Lafosse 4-5) in 20%. At mean follow-up (52.4 weeks), a significant increase in ROM, Relative Cuff Strength (from 57% to 90% compared to contralateral side), VAS (from 4 ±2.5 to 1±1.7), Constant (50±17.8 to 74 ±13.0), ASES (52 ±17.5 to 87 ±14.9), and UCLA (16± 4.9 to 30 ±4.9) scores were noted. There were six retears (10%), one failure due to P. acnes infection. 93% returned to pre-injury work and 89% of cases returned to pre-injury sport. Satisfaction rate was 96%. Muscle advancement technique for mRCT is a viable option with low retear rates, restoration of ROM, strength, and excellent functional outcomes

In currently used expansive laminoplasty (ELAP) for cervical spondylotic myelopathy (CSM), persistent axial pain, restriction of neck motion and loss of cervical l ordosis have been the significance postoperative problems. To prevent them, the author has developed skip laminectomy in which ordinary laminectomy at appropriate levels is combined with partial laminectomy of the cephalad half of laminae with preservation of the muscular attachments at adjacent levels. Since December 98, the author performed this procedure on 55 patients with CSM who required multilevel posterior decompressions. Twenty-one of these cases with follow-up period longer than 8 months, with an average of 12 months, were observed. In skip laminectomy, a consecutive four-level decompression between C3/4 and C6/7 as an example is accomplished by removing alternate laminae (C4 and C6), the cephalad half of the C5 and C7 lamina and the ligamentum flava at those four levels. The laminae to be removed were selected after analysis of the pre- and postoperative radiological findings. Intraoperative blood loss averaged 34 grams. The operation time averaged 128 minutes. The patients were allowed to sit up or walk on the first postoperative day without neck support of any kind. An average recovery rate according to the Japanese Orthopaedic Association score was 63%. None of these patients complained of residual axial pain. The postoperative ranges of neck motion on lateral X rays averaged 87% of the preoperative ranges. The spinal curvature index, according to Ishihara’s method, was reduced in only one of the 21 cases. Postoperative atrophy of the deep extensor muscles measured on T2 weighed axial MRI was minimal. Skip laminectomy is less damaging to the posterior extensor muscles and its use reduces the postoperative problems commonly seen after ELAP

Bilateral decompression of spinal stenosis may induce instability which compromises outcome. In an attempt to overcome this problem, bilateral decompression can be carried out through a unilateral approach. The ipsilateral side is decompressed by hemi-laminectomy with undercutting partial facetectomy and the contra-lateral side is treated by careful excavation beneath the spinous processes and laminae with preservation of the laminae, posterior ligament complexes and paraspinal muscles. This is achieved with the aid of an operating microscope or loupe and headlight. Previous reports contain little information about outcome and complications. We reviewed 30 patients with bilateral spinal stenosis, but without significant spondylolisthesis who were decompressed bilaterally from a unilateral approach by a single surgeon during a calendar year. They represented a third of our annual operations for spinal stenosis. Thirty patients had 45 levels decompressed. Female to male ratio was 2:1 and average age was 66 years. The average duration of preoperative symptoms was 1.6 years. The mean follow up period was 30 weeks (12 weeks to one year). Assessment was carried out using the Oswestry Disability Index, pre- and post-operative visual analogue pain scores for leg pain and back pain, walking distance and MacNab criteria of patient outcome. Results: improvement in Oswestry Disability Index, pain scores for sciatica and back pain and improved walking distance. All but one case had good or excellent outcome. Complications: one dural tear and two cases with temporary dermatomal sensory change. Whilst the technique is safe, and effective, a longer randomised controlled study is needed to demonstrate any real advantage over traditional approaches

Purpose: Ossification (YLO) and calcification (YLC) of the yellow ligaments constitute an exceptional pathological situation described almost exclusively in Japan. We report a retrospective series of 19 patients from the French West Indies followed between 1996 and 2003. Material and methods: The series included six men and thirteen women, mean age 67.8 years (31–79). A neurological examination was performed in all patients. Positive diagnosis was based on computed tomography results. MRI was performed in fifteen patients. Twelve patients underwent surgery (eight for laminectomy and four for laminoplasty). Operative specimens were analysed. The Rankin score was used to assess treatment efficacy. Results: The patients generally consulted for progressive aggravation of gait disorders. Physical examination disclosed spastic tetra- or paraparesia associated with a pyramidal reflex syndrome and sphincter disorders. Computed tomography provided the positive and differential diagnosis. YLO was seen as a linear hyperdensity underlining the laminae, generally at the lower thoracic level (T9–T12 in six of ten patients). YLC was found at the lower cervical level in nine of the nine patients and appeared as round bilateral hyperdensities independent of the laminae. MRI revealed cord involvement seen as a high intensity signal on T2 sequences. The fifteen operated patients improved 1 to 3 points on the Rankin scale. Prognosis was better for YLC. Pathology examination revealed cartilaginous metaplasia of the yellow ligament leading to laminar bone for the YLO and microcrystal deposits (calcium pyrophosphate and/or hydroxyapatite) for he YLC. Discussion: YLO and YLC are exceptional pathologies. More than 90% of the cases have been described in Japan and only one case in a black patient has been reported. YLO generally affects men in the fifth decade, YLC more often women after the age of 65 years. Positive and differential diagnosis are provided by CT scan. MRI visualises cord involvement. Treatment is based on posterior decompression. Prudence is particularly important for YLO due to dural adherences and the risk of dural breaches. Conclusion: The frequency of YLO and YLC appears to be underestimated in the black population. These conditions can lead to severe myelopathy. Treatment is based on posterior decompression, best performed before appearance of a high intensity signal on the MRI

The standard approach of diagnosing and monitoring scoliosis involves using the Cobb angle from posteroanterior (PA) radiograph. This approach has two key limitations: 1) It involves exposing the patients to ionising radiation during a period of heightened radiosensitivity. 2) The 2D x-ray image is a projection image of a 3D deformity and the Cobb angle represents only lateral rotation. 3DUS would overcome both these limitations. We developed a 3DUS system by combining motion capture technology, a conventional 2D ultrasound scanner and bespoke software. An ex vivo experiment and a pilot clinical study were carried out to demonstrate the system's ability in identifying vertebrae landmarks and quantifying the curvature. For the ex vivo validation, a spine phantom was created by 3D-printing a segmented abdo-pelvis CT scan. The spine phantom was then scanned using 3DUS and the level of agreement in the dimensions measured using 3DUS and CT was assessed. An 11 year old female with adolescent idiopathic scoliosis (AIS) was scanned with 3DUS. The SP co-ordinates were projected on a plane of best-fit to compare the curvature angle from 3DUS with the Cobb angle from the x-ray image. The spinous (SP), transverse processes and the laminae demonstrated high echogenicity and were easily identifiable. The difference between the spine phantom inter-SP dimension measurements made in 3DUS and CT was <2.5%. The PA x-ray of the AIS patient revealed 47° (L4-T11) and 52° (T6-T11) curves. 3DUS was able to represent the deformity in 3D revealing complex curvatures in all planes. The curvature angle from derived from 3DUS for the L4-T11 and T6-T11 curves were 132° (48°) and 125° (55°) respectively. The results of this pilot study demonstrate 3DUS as a promising tool for imaging spine curvature

Aims

Surgical approaches to cervical ossification of the posterior longitudinal ligament (OPLL) remain controversial. The purpose of the present study was to analyze and compare the long-term neurological recovery following anterior decompression with fusion (ADF) and posterior laminectomy and fusion with bone graft and internal fixation (PLF) based on > ten-year follow-up outcomes in a single centre.

Introduction. Kinematics analyses of the spine have been recognized as an effective method for functional analysis of the spine. CT is suitable for obtaining bony geometry of the vertebrae but radiation is a clinical concern. MRI is noninvasive but it is difficult to detect bone edges especially at endplates and processes where soft tissues attach. Kinematics analyses require tracking of solid bodies; therefore, bony geometry is not always necessary for kinematics analysis of the spine. This study aimed to develop a reliable and robust method for kinematics analysis of the spine using an innovative MRI-based 3D bone-marrow model. Materials and Methods. This IRB-approved study recruited 17 patients undergoing lumbar decompression surgery to treat a single-level symptomatic herniation as part of a clinical trial for a new dynamic stabilization device. T1 & T2 sagittal MRI scans were acquired as part of the pre-operative evaluation in three positions: supine and with the shoulders rotated 45° to the left and right to induce torsion of the lumbar spine. 3D bone-marrow models of L5 and S1 at the neutral and rotated positions were created by selecting a threshold level of the bone-marrow intensity at bone-marrow/bone interface. Validated 3D-3D registration techniques were used to track movements of L5 and S1. Segmental movements at L5/S1 during torsion were calculated. Results. Bone-marrow models were created not only in the vertebral body but also in superior/inferior, transverse and spinous processes, pedicles and laminae. Segmental rotation (mean±SD) at L5/S1 was shown to be symmetric for both left and right motions (p=0.149; Left: 1.04°±0.93° and Right: 1.33°±0.80°). The range of motion recorded was: left [0.05°-3.70°] and right [0.35°-3.25°]. These values were equivalent to previously reported values of axial lumbar rotation measured by 3D CT lumbar models. Conclusions. This study demonstrated feasibility of kinematic analyses using the 3D bone-marrow model created with clinical MRI. The bone-marrow model shows the bone-marrow/bone interface geometry –the internal structure of the vertebra rather than outside geometry usually used for kinematic analyses– that is easily and consistently detected due to its high-contrast interface MRI intensity, which does not require lengthy manual tracing of the bony contour. The bone-marrow model includes key elements of the vertebra including posterior elements and the 3D-3D registration technique used for 3D-CT model can be applied (Fig.1). This type of methodology can be used in the clinic to evaluate with sufficient accuracy subject-specific spinal kinematics without exposure to additional radiation. The MRI-based 3D bone-marrow model may also be useful for kinematic analyses of other major joints such as hip, knee, ankle and shoulder joints

Aims: We studied the ulnar nerves of five cadaveric specimens at Guyon’s canal to determine the presence, incidence and position of Renaut bodies. These are fusiform structures composed of fibroblast-like cells found within the endoneurium. Although their aetiology and role is unconfirmed, they do show a predilection for sites of nerve entrapment. Methods: Following dissection of the ulnar nerve sections were stained with toluidine blue and immunostains to demonstrate either Schwann cells, basal laminae, or axons. Fascicular topography, the number of perineurial cell layers and the number and distribution of Renaut bodies were recorded for each section. Results: Two points arise from our demonstration of a consistent appearance of Renaut bodies at the deep distal hiatus of Guyon’s canal. First, markers of subclinical nerve compression are present. Second, our results show that this subclinical compression occurs not in Guyon’s canal itself, but at its deep exit, the deep distal hiatus. Conclusion: These findings have clinical implications for the relief of Guyon’s canal syndrome. Decompression of the space alone may not be adequate. It would seem reasonable to argue that to optimise conditions for nerve recovery, the deep distal hiatus should be released as routine in all Guyon’s canal decompression procedures

Twenty-seven patients with neurological deficit due to burst fractures were treated with fresh frozen allografts following anterior spinal decompression. Their mean age was 28 years. In 19 patients the injury was due to motor vehicle accidents and in five to falls. The mean preoperative kyphosis was 19° (4° to 33°). Three patients with laminae fractures, which resulted in entrapment of the dura, underwent posterior decompression and transpedicular fixation before anterior decompression. Corpectomy was performed in all patients. An appropriate length of femoral allograft was positioned by interference fit and the spine was stabilised with an anterior rod screw construct in 21 patients. The follow-up ranged from 29 to 72 months. Bridwell grade-I fusion was seen in 23 patients at two years. Subsequent follow-up revealed no fracture, resorption or collapse. The mean neurological recovery was 1.4 Frankel grades. Nine patients (37%) made a complete recovery but in four (16%) there was no improvement. The mean postoperative kyphosis was 9° and at two years the mean loss of correction was 3°. One patient presented with a psoas abscess at two-year follow-up. At surgery the graft was partially resorbed but was stable. At six-year follow-up the patient was asymptomatic with a grade-II fusion. The use of allografts saves considerable time in surgery and avoids potential donor site morbidity. They are versatile and are easily available

This review provides a concise outline of the advances made in the care of patients and to the quality of life after a traumatic spinal cord injury (SCI) over the last century. Despite these improvements reversal of the neurological injury is not yet possible. Instead, current treatment is limited to providing symptomatic relief, avoiding secondary insults and preventing additional sequelae. However, with an ever-advancing technology and deeper understanding of the damaged spinal cord, this appears increasingly conceivable. A brief synopsis of the most prominent challenges facing both clinicians and research scientists in developing functional treatments for a progressively complex injury are presented. Moreover, the multiple mechanisms by which damage propagates many months after the original injury requires a multifaceted approach to ameliorate the human spinal cord. We discuss potential methods to protect the spinal cord from damage, and to manipulate the inherent inhibition of the spinal cord to regeneration and repair. Although acute and chronic SCI share common final pathways resulting in cell death and neurological deficits, the underlying putative mechanisms of chronic SCI and the treatments are not covered in this review.

Collagen meniscus implant (CMI) is a tissue engineering technique for the management of irreparable meniscal lesions. In this study we evaluate morphological and biochemical changes occurring in CMI after implantation. Gene expression technique was also adopted to characterise the phenotype of the invading cells. Light microscopy, immunohistochemistry (type I and II collagen), SEM and TEM analysis were performed on five biopsy specimens harvested from five different patients (range, 6 to 16 months after surgery). Fluorophore-assisted carbohydrate electrophoresis (FACE) and real-time PCR evaluation were carried out on two biopsy specimens harvested 6 and 16 months, respectively, after implantation. All these investigations were also applied on non-implanted scaffolds for comparison. Scaffold sections appeared to be composed of parallel connective laminae, connected by smaller connective bundles surrounding elongated lacunae. In the biopsy specimens, the lacunae were filled by connective tissue with newly formed vessels and fibroblast-like cells. Immunohistochemistry revealed exclusively type I collagen in the scaffold, while type II collagen appeared in the biopsy specimens. FACE analysis carried out in the scaffold did not detect any GAG disaccharides. Conversely, disaccharides were detected in the implants. Real-time PCR showed a signal only for collagen type I. In the scaffolds no gene expression was recorded. The morphological findings demonstrate that CMI is a biocompatible scaffold available for colonisation by connective cells and vessels. Biochemical data show a specific production of extracellular matrix after implantation. The absence of signal for type II collagen gene can be attributed to different maturation stages of the in-growing tissue

INTRODUCTION. Surgical correction of spinal deformities in the growing child can be applied with or without fusion. Sublaminar wiring, first described by Luque, allows continuation of growth of the non-fused spine after correction of the deformity. Neurological complications and wire breakage are the main clinical problems during the introduction and removal of currently used sublaminar wires. In this pilot study a posterior hybrid construction with the use of a medical-grade UHMWPE (Dyneema Purity®) sublaminar wire was assessed in an ovine model. We hypothesized that such a hybrid construction can safely replace current titanium laminar wires, while providing sufficient stability of the non-fused spinal column with preservation of growth. MATERIALS AND METHODS. This study included 6 Tesselaar sheep, age 7±2months. Two pedicle screws (Legacy system, Medtronic) were placed at lumbar level. Four consecutive laminae were attached to two titanium bars (4.5 mm) using 3 mm diameter UHMWPE (Dyneema Purity®) on the left side and 5 mm diameter on the right side. The sublaminar wires were fixed with a double loop sliding knot and tightened with a tensioning device. As a control, in one animal titanium sublaminar wires (Atlas cable, Medtronic) were applied. After sacrifice the spine of the animals was harvested. Radiographs were taken and CT scans were performed. The vertebrae were dissected and placed in formaldehyde for macroscopic and histological evaluation. RESULTS. The animals were sacrificed after a (minimal) postoperative period of 15 weeks. One animal developed a wire fistula and one animal died the first postoperative day due to complications of the anesthesia. None of the 3 or 5 mm knots loosened and no neurological complications occurred. An average of 8.7 mm growth was seen over the segment operated on. Computed tomography confirmed the preserved stability. Even though no decortication was performed, variable bone bridges with fused levels were seen on CT. Macroscopic and histological analysis showed no inflammation at lamina and dura levels containing Dyneema Purity®, with the exception of the case with the fistula where it was observed locally. DISCUSSION. This pilot animal model study shows that the UHMWPE laminar wire made by Dyneema Purity® has good handling and tensioning properties and can provide sufficient stability in fusionless spinal instrumentation while allowing substantial growth. The examined model showed to be a feasible spinal study model, without occurrence of neurological problems. Reactive periostal bone formation with fusion levels led to some restrictions in this model. In the future it will be necessary to test the described construction in a large animal scoliosis model

INTRODUCTION: In guided tissue regeneration a membrane is used for defect isolation to protect it against invasion from surrounding tissues and to keep intrinsic healing factors ‘in situ’. This technique has been successfully used in maxillo-facial surgery, but short experience has been reported in long-bone defects, with synthetic membranes and with variable results. In the other hand, calcification and ossification inside the arterial wall have been described. OBJECTIVE: The aim of the study was to evaluate the use of cryopreserved aorta allografts as membranes for guided tissue regeneration in comparison with expanded poly-tetra-fluoro-ethylene (e-PTFE) synthetic membranes. MATERIAL & METHODS: Prospective, randomized, blinded study in 15 New-Zeland rabbits. 10 mm mid-diaphyseal defects were created in both radii: 10 defects were covered with a cryopreserved aortic allograft as a tube, 10 with an e-PTFE membrane and 10, with no barrier membrane, served as controls. Animals sacrifice at 6–12–24–30 months. Studies: X-rays, CT, MR, morpho-densitometric analysis, electronic and optical microscopy. Immuno-cytochemistry on tissues and arterial wall cells cultured. RESULTS: None of the control defects healed. Nine defects covered with an artery completely reconstituted, but only six of those covered with e-PTFE, with a nearly normal cortical-medullar pattern and with progressive increasing in density and thickness of medullar and cortical to values similar to those of the normal bone. Histological studies showed no inflammatory response to the arterial graft, direct union between the artery and the regenerated bone and even mature bone between the elastic laminae of the arterial wall, suggesting superior biocompatibility properties. Immuno-cytochemistry and ultrastructural studies suggest that arterial allografts could act not only as membrane barriers, with additional osteoinductive properties due to trans-differentiation of viable arterial wall cells (endothelial, smooth muscle and/or tissue specific stem cells) towards osteoblastic cells, and also due to ossification secondary to changes in proteins of the arterial extracellular matrix. This could be the application of the process of arterial wall calcification and ossification (usually seen in arteriosclerosis, gender, diabetes or kidney failure) for regeneration of long-bone defects. CONCLUSION: Cryopreserved aortic allografts can be used as membrane barriers for guided bone regeneration, with superior results to e-PTFE membranes

Background and objective: In guided tissue regeneration a membrane is used for defect isolation to protect it against invasion from surrounding tissues and to keep intrinsic healing factors ‘in situ’. This technique has been successfully used in maxillo-facial surgery, but short experience has been reported in long-bone defects, with synthetic membranes and with variable results. In the other hand, calcification and ossification inside the arterial wall have been described. The aim of the study was to evaluate the use of cryopreserved aorta allografts as membranes for guided tissue regeneration in comparison with expanded poly-tetra-fluoro-ethylene (e-PTFE) synthetic membranes. Methods: Prospective, randomized, blinded study in 15 New-Zeland rabbits. 10 mm mid-diaphyseal defects were created in both radii: 10 defects were covered with a cryopreserved aortic allograft as a tube, 10 with an e-PTFE membrane and 10, with no barrier membrane, served as controls. Animals sacrifice at 6-12-24-30 months. Studies: X-rays, CT, MR, morpho-densitometric analysis, electronic and optical microscopy. Immuno-cytochemistry on tissues and arterial wall cells cultured. Results: None of the control defects healed. Nine defects covered with an artery completely reconstituted, but only six of those covered with e-PTFE, with a nearly normal cortical-medullar pattern and with progressive increasing in density and thickness of medullar and cortical to values similar to those of the normal bone. Histological studies showed no inflammatory response to the arterial graft, direct union between the artery and the regenerated bone and even mature bone between the elastic laminae of the arterial wall, suggesting superior biocompatibility properties. Immuno-cytochemistry and ultrastructural studies suggest that arterial allografts could act not only as membrane barriers, with additional osteoinductive properties due to trans-differentiation of viable arterial wall cells (endothelial, smooth muscle and/or tissue specific stem cells) towards osteoblastic cells, and also due to ossification secondary to changes in proteins of the arterial extracellular matrix. This could be the application of the process of arterial wall calcification and ossification (usually seen in arteriosclerosis, gender, diabetes or kidney failure) for regeneration of long-bone defects. Conclusion: Cryopreserved aortic allografts can be used as membrane barriers for guided bone regeneration, with superior results to e-PTFE membranes

The lumbar spine consists of a mobile segment of 5 vertebrae, which are located between the relatively immobile segments of the thoracic and sacral segments. The bodies are wider and have shorter and heavier pedicles, and the transverse processes project somewhat more laterally and ventrally than other spinal segments. The laminae are shorter vertically than are the bodies and are bridged by strong ligaments. The spinous processes are broader and stronger than are those in the thoracic and cervical spine. Internal fixation as an adjunct to spinal fusion has become increasingly popular in recent years. Stainless steel or titanium plates or rods are longitudinally anchored to the spine by hooks or pedicle screws. Powerful forces can be applied to the spine through these implants to correct deformity. Implants provide immediate rigid spinal immobilization, which allows for early patient mobilization, and provides a more optimal environment for bone graft incorporation. Numerous clinical and experimental studies demonstrate higher fusion rates in patients with rigid internal fixation than in controls without instrumentation. Although various implants are available, pedicle fixation systems are the most commonly used implant type in the lumbosacral spine. The large size of the lumbar pedicles minimizes the number of instrumented motion segments required to achieve adequate stabilization. Many authors have reported loss of postoperative deformity correction after transpedicular screw fixation, ranging from 2.5 degrees to 7.1 degrees. The general preference is to stabilize the fractured vertebra by fusing one level above and one level below. With this technique, the rate of loss of correction is high. At our institution, we routinely stabilize the unstable thoracolumbar fractures by fusing one level above and one level below. In addition, we put screws into the pedicle(s) of fractured vertebrae. The reason for this is the following:. To correct the deformed body of the fractured vertebra for better load sharing. To make use of the pedicles of the fractured vertebra for superior rotatory stabilization. To avoid the need for the inclusion of additional levels, thereby preserving motion segments. To avoid the need for possible anterior spinal fusion and instrumentation. To obtain a better correction of a kyphotic deformity. Plain radiographs were analysed post operatively and compared for reduction of the fracture fragments and correction of kyphotic deformity to pre-operative films. 74 Patients were admitted with thoracolumbar spine fractures to our hospital. 48 Patients were surgically treated, and 34 patients were available for follow up. We found that inserting the pedicle screws into the fractured vertebra provided good stabilization for very unstable fractures. No loss of correction was seen in the follow up x-rays. We conclude that including the fractured vertebra into the fracture fixation device not only provides better fracture reduction, but also gives improved rotatory stability

Aim: Collagen meniscus implant (CMI) is a tissue engineering technique for the management of irreparable meniscal lesions. In this study we evaluate morphological and biochemical changes occurring in CMI after implantation, in order to better define tissue ingrowth inside the scaffold. Gene expression technique was also adopted to characterize the phenotype of the invading cells. Methods and materials: Morphological analysis was performed by light microscopy, immunohistochemistry (type I and II collagen), SEM and TEM on 5 biopsy specimens, harvested from 5 different patients (range, 6 to 16 months after surgery). Biochemical evaluation was carried out using Flurophore Assisted Carbohydrate Electrophoresis (FACE): this assay allowed to measure glycosaminoglycans (GAG) production in extracellular matrix of 2 biopsy specimens, harvested respectively 6 and 16 months after implantation. Real Time PCR was performed on the same 2 biopsy samples for detecting tissue-specific gene expression (collagen); RNAaseP gene expression was used as housekeeping gene. All these investigations were also applied on non implanted scaffolds for comparison. Results: Scaffold sections appeared composed by parallel connective laminae of 10-30B5m, connected by smaller (5-10B5m) connective bundles, surrounding elongated lacunae of 40-60B5m in diameter. In the biopsies specimens, the lacunae were filled by connective tissue with newly formed vessels and fibroblast-like cells. In the extracellular matrix, the collagen fibrils showed uniform diameters. The original structure of CMI was still recognizable and no inflammatory cells were detected inside the implant. A more organized architecture of the fibrillar network was evident in specimens with longer follow-up. Immunohistochemistry revealed exclusively type I collagen in the scaffold, while type II collagen appeared and was predominant in the biopsies specimens. FACE analysis carried out in the scaffold did not detect any GAG disaccharides. Conversely, high amount of disaccharides (unsulphated chondroitin, 4 and 6 sulphated chondroitin) were detected, together with hyaluronan, in the implants. Real Time PCR showed signal for Collagen type I alpha 1 and no signal for Collagen type II alpha 1. In the scaffolds used for comparison, no gene expression was recorded. Conclusions: The morphological findings of this study demonstrate that CMI acts as a biocompatible scaffold which provide a three-dimensional structure available for colonization by connective cells and vessels. Biochemical data are consistent with an active and specific production of extracellular matrix in the scaffold after implantation. The absence of signal for type II collagen gene in biopsies specimens can be attributed to different maturation stages of the ingrowing tissue

INTRODUCTION: Intervertebral degeneration is characterised by instability due to permanent decrease in the stiffness of the intervertebral segment and concentration of stress upon the posterior portion of the disc, and by morphologic changes in the posterior elements due to posterior displacement of loading, notably enlargement of the lamina and zygapophyseal joints. These changes lead to reduction in the cross-sectional area of the vertebral canal. In order to counterbalance these changes, an implant has been developed with an interspinous blocker and an artificial ligament made of Dacron. This obviates the need for a permanent fixation in the vertebral bone, avoiding the risk of loosening. Inhibition of hyperextension limits narrowing of the posterior canal, resulting in an increase in its cross-sectional area of up to 40%. A first-generation implant for nonrigid stabilisation of lumbar segments was developed in 1986 with a titanium interspinous blocker. Following an initial observational study in 1988 and a prospective controlled study from 1988 to 1993, more than 300 patients have been treated for degenerative lesions with significant resolution of residual low back pain with no serious adverse effects. After careful analysis of the points that could be improved,a second-generation,improved implant called the ‘Wallis implant’ was developed with a redesigned blocker made of PEEK (polyetheretherketone), a more resilient material. METHODS: Biomechanical studies were used to verify the effectiveness of this implant in increasing intervertebral stiffness, reducing mobility, and unloading the facet joints and the posterior portion of the disc. A prospective multicenter international observational study was begun a year ago. RESULTS: Preliminary results confirm the clinical efficacy of this treatment on low back pain and nerve root symptoms, especially in recurrent disc herniation and canal stenosis. DISCUSSION: Nonrigid intervertebral fixation with the Wallis implant clearly appears to be a useful technique in the management of initial forms of degenerative intervertebral lumbar disc disease. The method should rapidly assume a specific role along with total disc prostheses in the new step-wise surgical strategy to obviate definitive fusion of degenerative intervertebral segments. Moreover, dynamic stabilisation with the Wallis system is totally reversible and leaves all other options open. Wallis is recommended for patients with lumbar disc disease who have: (i) discectomy for massive herniated disc leading to substantial loss of disc material, (ii) a second discectomy for recurrence of herniated disc, (iii) discectomy for herniation of a transitional disc with sacralization of L5, (iv) degenerative disc disease at a level adjacent to a previous fusion or prosthesis, (v) isolated disc resorption, notably with concomitant type-1 Modic changes, associated with low back pain, or (vi) symptomatic narrow canal treated by resection of the superior aspect of the laminae

Introduction: Hook displacement or pullout is a common complication compromising the stability of spinal instrumentation. The two most common causes are the loss of the optimal adjustment between hook and lamina during the connection of the implant to the rod and the displacement of the hook during correction maneuvers. Therefore, a partially constrained rod-implant link was conceived allowing for free rotation in the sagittal plane while maintaining the possibility for transverse loading during correction maneuvers. One of the possible benefits of this system is the preservation of the adjustment between hook and lamina. Purpose of Study: To compare the adjustment obtained between hook and lamina by using a partially constrained pivot link (PL), connecting the hook to the rod while allowing for rotation in the sagittal plane, versus the common fully constrained link (FCL) connecting the hook rigidly to the rod. Methods: A plastic model of the lumbar spine was instrumented on one side with a L1 supralaminar hook and a L3 infralaminar hook. Seven lordotic configurations (range: −45° to −30°) were randomly assigned to the model. A prebent rod with a −41° lordosis between the fixation points was used for all tests. Compression was applied to the claw construct until the best fit between hooks and laminae was achieved. The PL hooks were secured to the rod by a top-loading clip system allowing for rotation in the sagittal plane until final fixation with an incorporated setscrew. The FCL hooks were secured to the rod with a top-loading plug screw. The length of the hook blade in contact with the lamina, the initial and final lordosis of the construct were measured. Results: The mean length of the hook blade in contact with the lamina was 6.9 mm for the PL infralaminar hooks versus 4.2 mm for the FCL infralaminar hooks (p< 0.0005). There was no statistically significant correlation between the degree of initial lordosis and the amountof contact achieved by both the FCL and PL infralaminar hooks (FCL: r = −0.052; PL: r = −0.585). Discussion: Using a partially constrained pivot link achieves a larger contact between hook and lamina than the common fully constrained link. This was statistically highly significant at the level of the strategically most important infralaminar hooks in a lordotic construct. Early clinical experience using a spinal instrumentation based on the pivot link principle in seventy patients seems to confirm the enhanced strength of fixation. Especially, the management of spinal deformities in patients with severe osteoporosis or dystrophic lesions of the spine is significantly improved. Significant implant volume reduction allows for the use of this system even in young children

There can be no doubt that bone morphogenetic proteins play a hierarchic role in the osteogenetic cascade. Pre-clinical and clinical trials have confirmed their decisive role in achieving anterior lumbar fusion, as they direct mesenchymal stem cells toward osteoblastic lineages.The present study is concerned with initial experience in the application of autologous mesen-chymal stem cells and various growth factors (BMP-7,VEGF,TGFbeta) in the treatment of paediatric spinal pathologies. Eleven patients affected by serious forms of congenital infantile scoliosis, idiopathic scoliosis and grade I spondylolisthesis received surgical treatment. In three patients with congenital infantile scoliosis, ages ranging from 3 to 12 years, the surgical procedure was an anterior and posterior fusion at the level of the hemiver-tebra, extending it to a level above and below it by means of in situ decortication of the vertebral plates and laminae on the convex side and delivery of stem cells taken from the iliac bone and applied in situ by means of bovine collagen sponge (Healos system). No fixation device was added. Plaster and brace were used during the postoperative course for 9 months. In two cases of intertransverse in situ fusion for grade I spondylolisthesis the age of the patients was 13 and 16 years, respectively, and the surgical procedure consisted in the standard technique to which was added delivery of a mixture composed of small bone chips obtained from decortication, 3.5 mg of eptotermin alpha (Op-1, BMP7), and autologous stem cells taken from iliac bone. A special form of informed consent was obtained for these two patients because of their incomplete bone maturity. TLSO was used in the postoperative course for 2 months. In the six patients with idiopathic scoliosis, ages ranged from 13 to 15 years and the treatment consisted in posterior instrumentation and fusion by means of rods, transpedicular screws and hooks; standard fusion techniques were supported by local bone chips obtained from decortication, placed on collagen sponges and combined with autologous stem cells taken from iliac bone with the addition of platelet gel derived from the autologous preoperative blood collection. No bone chips were taken from iliac wing. The results were evaluated by X-rays and CT at intervals of 1, 2, 4, 6 and 12 months. In the cases of congenital scoliosis a solid fusion area was obtained only for posterior hemiephysiodesis, without a parallel bone signal of fusion at the anterior level. In the cases of intertransverse in situ fusions for spondy-lolisthesis there was a beginning fusion already visible on the first X-ray control 1 month postopoeratively, confirmed at successive check-ups and maintained in the follow-up. The cases of idiopathic scoliosis showed an initial ossification of the grafts and signals of fusion at the 6-month check-up. The isolated use of stem cells, although promising from a theoretical point of view, did not prove encouraging in the cases of anterior fusion. It is most probable that the absence of instrumentation induced a defect in the stable fixation of the fused segments, the latter being a crucial factor.The cases of in situ fusion for spondylolisthesis confirm the hierarchic role of the bone morphogenetic protein 7 in inducing the mesenchymal stem cells, released in situ from decortication, toward osteoblastic lineage. To our knowledge these represent the first two cases of use of OP-1 in patients younger than 18 years. In the fusion areas which are more extensive in length (idiopathic scoliosis) the added use of autologous stem cells mixed with platelet gel seems to improve the physiological processes of fusion. It will be necessary to monitor the long-term results of these procedures with special regard to loss of correction and weakness of the fusion area causing torsional or flexion-extension stress. These possible costs have to be compared with the verified benefits of a better use of blood in its capacity to save on corresponding haemotransfusion, combined with the absence of comorbidity related to the donor site of iliac bone chips

Injuries of the cervical spine can be classified into six categories according to a mechanistic system describing the biomechanical deficiencies incurred in a cervical spine injury. However high velocity flexion compression loads cause multiple contiguous and noncontiguous fractures due to multiple force vectors. A universal classification system cannot be applied. Instability exists if there is greater than 3.5 mm of translation or greater than 11 degrees of angulation as compared to other segments. The degree of ligamentous injury on MRI correlates with instability in patients with lateral mass facet fractures, with rupture of multiple ligaments including the anterior longitudinal, posterior longitudinal, interspinous, or facet capsule. Patients with less than 13 mm of narrowing of the sagittal canal are predisposed to neurologic injury. Vertical compression injuries cause canal occlusion and vertebral column shortening. The timing of surgery in cases of spinal cord injury is controversial. There is no difference in outcome between early (< 72 hours) and late (> 5 days) surgery. However, there remains at least a theoretical benefit to early surgery. Compression-flexion injuries result in loss of the anterior column by compression followed by the posterior column in distraction. The injury is considered unstable if there is a vertical cleavage fracture of the vertebral body or displacement. Treatment includes a cervical orthosis or halo for minor injuries, depending on the degree of kyphosis. Major injuries with displacement should be treated surgically by anterior corpectomy and plate or an anterior/posterior fusion, depending on the degree of posterior instability. The most common level of vertical-compression injuries is at the C6 or C7 level. Minimally displaced injuries can be treated with a collar or halo. Fragmentation and peripheral displacement of the bony fragments needs a halo followed by surgery and this may include an anterior corpectomy and plating. Distraction-flexion injuries may result in facet sub-luxation with less than 25% displacement, or dislocation of one (UFD) or both (BFD) facet joints. When there is 3 mm of translation (25%), the canal is occluded 20–25%. With 6mm of translation (50%), there is 40–50% canal occlusion. MRI can help analyse the soft tissue and ligamentous injuries. In UFD, all posterior ligamentous structures including joint capsule, and half the disc annulus are disrupted. Disruption of ALL and PLL is not necessary to create a UFD. In addition to the posterior structures, the ALL, the PLL and disc are disrupted in BFD. Rupture of the intervertebral disc may include posterior herniation or circumferential disruption. All distraction flexion injuries should be reduced closed. The necessity of a preoperative MRI is undetermined. Preoperative MRI is recommended if there is an unreliable exam due to the patient being uncooperative, if there is neurological worsening with, or failure of closed reduction. If the patient is neurologically intact and closed reduction successful, a posterior cervical fusion is advocated if there is no evidence of an extruded disc on the post reduction MRI. If the closed reduction failed, or MRI indicated, and there is no evidence of a herniated disc, an open posterior reduction followed by fusion is performed. Anterior discectomy with reduction, a graft and a plate is performed for a herniated disc. Compression-extension injuries fail by compression of the posterior elements followed by distraction of the anterior elements. There are unilateral or bilateral fractures of the laminae/neural arch with degrees of displacement. Undisplaced neural arch fractures can be treated with a cervical orthosis or halo. Displaced neural arch fractures are treated with a posterior cervical fusion. There are two stages in the distraction-extension injury group. The anterior longitudinal ligament is disrupted with possibly a transverse fracture of the body. With more major injuries, there is a significant displacement injuring the posterior column. Stage 1 injuries can be treated with a halo and Stage 2 with an anterior decompression and fusion with a plating device. There are two stages to lateral flexion injuries. Minor injuries include asymmetric centrum fracture and a unilateral arch fracture. In addition, there is displacement of the body with contralateral ligamentous failure in major injuries. The treatment for Stage 1 is usually a collar while treatment for Stage 2 is usually a posterior cervical fusion. Posterior stabilization procedures may be performed with wires and cables with or without rods. Posterior clamps usually are not recommended; while plates and screws are preferred. The plates and screws are biomechanically superior to wiring and avoid canal penetration. They are ideal when there is loss of the posterior elements. Pedicle fixation should be considered when operating on the C2 or C7 level. One in five patients may have complete disruption of vertebral artery blood flow. This occurs most commonly with flexion-distraction or flexion-compression injuries. Vertebral artery evaluation is recommended in patients with flexion injuries and symptoms consistent with vertebral artery insufficiency. It is important to understand the mechanism of injury; to understand which elements are compromised. We have to get the appropriate imaging studies, we have to be cognizant of the fact that the vertebral artery may be injured, or there may be an associated herniated disc. We have to understand the degree of instability, which dictates the appropriate treatment and we have to understand the risk benefit of the specific internal fixation systems that we use