To analyze the dynamics of the thoracic spine during deep breathing in AIS patients and in healthy matched controls. Case-control cross-sectional study. 20 AIS patients (18 girls, Cobb angle, 54.7±7.9°; Risser 1.35±1.2) and 15 healthy volunteers (11 girls) matched in age (12.5 versus 15.8 yr. mean age) were included. In AIS curves, the apex was located in T8 (14) and T9 (6). Conventional sagittal radiographs of the whole spine were performed at maximal inspiration and expiration. The ROM of each spinal thoracic functional segment (T1-T7, T7-T10, T10-T12), the global T1–T12 ROM were measured. Respiratory function was assess by forced vital capacity (FVC), expiratory volume (FEV1), FEV1/FVC, inspiratory vital capacity (IVC) and peak expiratory flow (PEF). In healthy subjects, the mean T1–T12 ROM during forced breathing was 16.7±3.8. AIS patients showed a T1-T12 ROM of 1.1±1.5 (p<0.05) indicating a sagittal stiffness of thoracic spine. A wide T7–T10 ROM (15.3±3.0) was found in healthy controls (91.6% of the T1–T12 ROM). AIS patients showed only 0.4±1.4 ROM at T7-T10 (36.4% of the T1–T12 ROM) (p<0.001). There was a significant correlation between T7-T10 ROM and IVC. Lenke 1A AIS patients show a restriction of the thoracic spine motion with an almost complete abolition of T7-T10 ROM, a crucial segment participating in the deep breathing. T7-T10 stiffness could explain the ventilatory limitations found in AIS patients

In healthy subjects, respiratory maximal volumes are highly dependent on the sagittal range of motion of the T7-T10 segment. In AIS, the abolition of T7-T10 dynamics related to the stiffness induced by the apex region in Lenke IA curves could harm ventilation during maximal breathing. The aim of this study was to analyze the dynamics of the thoracic spine during deep breathing in AIS patients and in healthy matched controls. This is a cross-sectional, case-control study. 20 AIS patients (18 girls, Cobb angle, 54.7±7.9°; Risser 1.35±1.2) and 15 healthy volunteers (11 girls) matched in age (12.5 versus 15.8 yr. mean age) were included. In AIS curves, the apex was located at T8 (14) and T9 (6). Conventional sagittal radiographs of the whole spine were performed at maximal inspiration and exhalation. The ROM of each spinal thoracic functional segment (T1-T7, T7-T10, T10-T12) and the global T1-T12 ROM were measured. In healthy subjects, the mean T1-T12 ROM during forced breathing was 16.7±3.8. AIS patients showed a T1-T12 ROM of 1.1±1.5 (p<0.05), indicating a sagittal stiffness of the thoracic spine. A wide T7-T10 ROM (15.3±3.0) was found in healthy controls (91.6% of the T1–T12 ROM). AIS patients showed only 0.4±1.4 ROM at T7-T10 (36.4% of the T1-T12 ROM) (p<0.001). There was a significant positive correlation between the magnitude of T7-T10 kyphosis in maximal exhalation and both FVC (% of predicted FVC) and FEV1. In conclusion, Lenke 1A AIS patients show a restriction of the thoracic spine motion with an almost complete abolition of T7-T10 ROM, a crucial segment for deep breathing. T7-T10 stiffness could explain the ventilatory limitations found in AIS patients

Introduction. Adolescent Idiopathic Scoliosis (AIS) is a three-dimensional deformity of the spine with unclear etiology. Due to the asymmetry of lateral curves, there are differences in the muscle activation between the convex and concave sides. This study utilized a comprehensive thoracic spine and ribcage musculoskeletal model to improve the biomechanical understanding of the development of AIS deformity and approach an explanation of the condition. Methods. In this study, we implemented a motion capture model using a generic rigid-body thoracic spine and ribcage model, which is kinematically determinate and controlled by spine posture obtained, for instance, from radiographs. This model is publicly accessible via a GitHub repository. We simulated gait and standing models of two AIS (averaging 15 years old, both with left lumbar curve and right thoracic curve averaging 25 degrees) and one control subject. The marker set included extra markers on the sternum and the thoracic and lumbar spine. The study was approved by the regional Research Ethics Committee (Journal number: H17034237). Results. We investigated the difference between the muscle activation on the right and left sides including erector spinae (ES), psoas major (PS), and multifidus (MF). Results of the AIS simulations indicated that, on average throughout the gait cycle, the right ES, left PS and left MF had 46%, 44%, and 23% higher activities compared to the other side, respectively. In standing, the ratios were 28%, 40%, and 19%, respectively. However, for the control subject, the differences were under 7%, except ES throughout the gait, which was 17%. Conclusion. The musculoskeletal model revealed distinct differences in force patterns of the right and left sides of the spine, indicating an instability phenomenon, where larger curves lead to higher muscle activations for stabilization. Acknowledgement. The project is funded by the European Union's Horizon 2020 program through Marie Skłodowska-Curie grant No. [764644]

Background. Using flexible tethering techniques, porcine models of scoliosis have been previously described. These scoliotic curves showed vertebral wedging but very limited axial rotation. In some of these techniques, a persistent scoliotic deformity was found after tether release. The possibility to create severe progressive true scoliosis in a big animal model would be very useful for research purposes, including corrective therapies. Methods. The experimental ethics committee of the main institution provide the approval to conduct the study. Experimental study using a growing porcine model. Unilateral spinal bent rigid tether anchored to two ipsilateral pedicle screws was used to induce scoliosis on eight pigs. Five spinal segments were left between the instrumented pedicles. The spinal tether was removed after 8 weeks. Ten weeks later the animals were sacrificed. Conventional radiographs and 3D CT-scans of the specimens were taken to evaluate changes in the coronal and sagittal alignment of the thoracic spine. Fine-cut CT-scans were used to evaluate vertebral and disc wedging and axial rotation. Results. After 8 weeks of rigid tethering, the mean Cobb angle of the curves was 24.3 ± 13.8 degrees. Once the interpedicular tether was removed, the scoliotic curves progressed in all animals until sacrifice. During these 10 weeks without spinal tethering the mean Cobb angle reached 50.1 ± 27.1 degrees. The sagittal alignment of the thoracic spine showed loss of physiologic kyphosis. Axial rotation ranges from 10 to 35 degrees. There was no auto-correction of the curve in any animal. A further pathologic analysis of the vertebral segments revealed that animals with greater progression had more damage of the neurocentral cartilages and epiphyseal plates at the sites of pedicle screw insertion. Interestingly, in these animals with more severe curves, compensatory curves were found proximal and distal to the tethered segments. Conclusions. Temporary interpedicular tethering at the thoracic spine induces severe scoliotic curves in pigs, with significant wedging and rotation of the vertebral bodies. As detailed by CT morphometric analysis, release of the spinal tether systematically results in progression of the deformity with development of compensatory curves outside the tethered segment. The clinical relevance of this work is that this tether release model will be very useful to evaluate both fusion and non-fusion corrective technologies in future research. Level of Evidence. Not apply for experimental studies

The aim of our study is to investigate the relation between the intensity of pain in the thoracic and lumbar spine and morphometric parameters of vertebrae in postmenopausal women. Materials and methods. We have examined 250 postmenopausal women aged 50–79 years divided into two groups: 171 women without vertebral deformations and 79 women with confirmed vertebral fractures. The duration of pain syndrome after fracture was over 6 months. The presence and intensity of pain syndrome in the thoracic and lumbar spine were assessed using a visual analog scale (VAS). Morphometric analysis of the vertebral parameters was carried out using the VFA software of the dual-energy X-ray densitometer «Prodigy» (GE Medical systems, Lunar, model 8743, 2005). Results. The intensity of pain syndrome in the lumbar spine significantly correlates with L1 vertebral indices: A/P (r=−0.37, p=0.01) and M/P (r=−0.29, p=0.03) in women with normal BMD. The intensity of pain in the thoracic region correlates with Th10 vertebral indices: A/P (r=−0.45, p=0.0004) and M/P (r=−0.35, p=0.01) in women with osteopenia. We have not determined any significant relationship between the level of back pain and vertebral body size index in women with osteoporosis and without vertebral fractures. In 11% patients with confirmed wedge and compression vertebral fractures chronic pain syndrome is absent, and the presence of other fractures does not increase the frequency of back pain syndrome (14%). The presence of vertebral fractures significantly increases the risk of pain in the thoracic spine (RR=1.32; 95% CI: 1.09–1.60, p= 0.004). In patients with vertebral fractures the intensity of pain in the thoracic spine significantly correlates with indices of Th11-Th12vertebrae, and relates to the number and localisation of vertebral fractures. The level of pain in the lumbar region does not depend on the location and number of damaged vertebrae. Conclusion. In postmenopausal women without osteoporosis and vertebral fractures level of pain may be associated with initial vertebral deformation, limiting the spine transition zone. The presence of vertebral fractures increases the risk of pain syndrome in the thoracic region depending on the location and number of damaged vertebrae

Summary Statement. Pedicle screws provide robust fixation and rigid immobilization. There has been no attempt to correlate the anatomic dimensions of thoracic and lumbar pedicles with the accuracy of navigated insertion. This study demonstrates that comparable accuracy using this technique. Introduction. Pedicle screws provide robust mechanical fixation, which makes their use attractive; their use enables fixation of the three spinal columns. There remains concern about the potential both for misplacement; various investigators have studied the accuracy of pedicle screw insertions, comparing different techniques. What is not clear, however, is whether there is any relation between the variables of pedicles’ anatomic dimensions, screw dimensions and accuracy. This study aims to elucidate the relationship between these variables. Patients & Methods. We conducted a retrospective review of consecutive pedicle screws that were inserted in the thoracic and lumbar spine at our institution. Screws were inserted using the navigated method (Stealth Station® TREON™, Medtronic, Louisville, CO). The accuracy of the screw insertion was measured using the classification system developed by Gertzbein and Robbins; pedicle dimensions were measured from post-operative computed tomography scans. The corresponding pre-operative scans were then used to measure the pedicle dimensions at the other levels. The magnitude of a cortical breach in the pedicle was represented by a letter: A (no breach), B (<2mm), C (>2mm, <4mm), D (>4mm, <6mm) and E (>6mm). In addition, measurements were made of the anatomic dimensions of the pedicles. The combination of these two measures allowed for direct correlation to be made between the accuracy of screw insertion, screw dimensions and pedicle anatomy. We then computed the proportion of each pedicle (width) occupied by a screw. Results. A total of 765 screws were reviewed, 493 were in the thoracic spine and 272 in the lumbar spine. Of the screws in the thoracic spine, 472 (96%) were either fully in the pedicle or less than 2mm beyond the cortex (within the A+B classification); when considered separately, 323 (66%) were completely within the pedicle (A) and 149 (30%) were less than 2mm beyond the cortex. A total of 21 (4%) screws were beyond 2mm but within 6mm (C+D). In the lumbar spine, 270 (99%) were either completely within the cortex or less than 2mm exposed (classified as A or B). The nadir of pedicle width was at T4. From L1 to L5, measured pedicle width also rose. This pattern was followed, although it was less profound, when screw diameter was measured in the lumbar spine (and even less so in the thoracic vertebrae). The height of pedicles was noted to progressively increase, peaking at the thoraco-lumbar junction. The mid thoracic region was associated with screws occupying the greatest proportion of pedicle diameter. Discussion/Conclusion. The use of pedicle screws in the thoracic and lumbar spine remains relatively safe. The accuracy of navigated insertion was found to compare well to previous series’. Although there is some association between the anatomical dimensions of pedicles and the dimensions of screws, this doesn't seem to be a strong association. Based on the findings in this series, future studies that relate the long term outcome (e.g. failure or screw loosening) with proportion of pedicle diameter taken up by a screw may be warranted

Introduction. Risk factors for disc degeneration depend on how the condition is defined, i.e. on the specific disc degeneration “phenotype”. We present evidence that there are two major and largely-distinct types of disc degeneration. Methods. The relevant research literature was reviewed and re-interpreted. Evidence. In the . upper. lumbar and thoracic spine, disc degeneration is closely associated with endplate defects and with inflammatory changes in the vertebral bodies. It has a relatively high heritability (i.e. a strong genetic influence), and its incidence does not increase markedly with age. In the . lower. lumbar spine, disc degeneration is closely associated with radial fissures and nucleus herniation. Here it has a relatively low heritability, and a correspondingly stronger association with mechanical loading, and its incidence increases steadily throughout life. Mechanical experiments on cadaveric spines show that endplate fracture and nucleus herniation can be caused by compressive loading, and by bending combined with compression, respectively. Both lesions cause an immediate decompression of the nucleus, so that it becomes difficult to create subsequently the other lesion in the same disc. This suggests distinct phenotypes. Interpretation. The two types of disc degeneration are not entirely distinct, because disc herniation sometimes occurs at upper lumbar levels. Nevertheless, it may be useful to recognise two phenotypes when it comes to explaining and treating discogenic pain. Some other common disc changes (such as water loss and bulging) are attributable to ageing rather than degeneration, whereas disc narrowing probably represents a final common pathway for both types of disc degeneration. Conflicts of Interest. None. Source of Funding. None. This abstract has not been previously published in whole or in part; nor has it been presented previously at a national meeting

Background. Back pain has become a worldwide problem and excessive, repetitive rotation has been shown to cause tissue damage. A sleeping posture similar to that of the foetal position has been suggested to limit unnecessary rotation of the lumbar spine. The Rophi™ cushion, utilises this theory to provide spinal alignment and improved sleeping posture. This study aims to assess the subjective experience and biomechanical effects of the Rophi™ cushion in participants with simple mechanical lower back pain (LBP). Methods & Results. Fifteen participants (aged 44 ± 9.7 years) with simple mechanical LBP were recruited using the Red Flags screening form. The kinematics of the pelvis, lower limbs, lumbar and thoracic spine were analysed in six degrees of freedom whilst the participants lay in a semi-foetal position. Visual analogue scales were used to measure participant pain and discomfort levels during sleep pre and post a one week cushion intervention. Kinematic results show the main significant difference in joint angles occurred at the hip in all three planes, and between the lower lumbar region and the pelvis in the coronal plane. Subjective experience showed a reduction in the number of days with poor sleep quality and a significant reduction in frequency and intensity of lower back pain and stiffness when waking. Conclusions. Through repositioning of the hips and lower lumbar spine, overall it appears the individual is moved towards a more neutral position when using the Rophi™ cushion and a one week intervention shows a significant improvement in lower back pain on waking. Conflicts of Interest. None. Source of Funding. Funded by the NWDA Innovation voucher scheme. This abstract has not been previously published in whole or substantial part and has not been previously presented at a national meeting

Summary Statement. Using abdominal CT scans to evaluate bone mineral density following acute fractures of the thoracic and lumbar spine demonstrates significant levels of osteoporosis in older patients; this approach may help save on time and resources, and reduce unnecessary radiation exposure. Introduction. While a reduction in bone mineral density (BMD) is associated with aging, relatively few patients have formal dual-energy X-ray absorptiometry (DXA) to quantify the magnitude of bone loss, as they age. This loss of bone may predispose to fractures. Recent data, which correlates mean Hounsfield units (HU) in an area of the L1 vertebra with BMD, now makes it possible to screen for osteoporosis using incidental abdominal Computed Tomography (CT) scans to measure bone density. This innovation has the potential to reduce both cost and radiation exposure, and also make it easier to identify patients who may be at risk. The aims of this study were to evaluate the utility of this approach in patients with acute thoracic and lumbar spine fractures and to evaluate the impact of aging on BMD, using CT screening. Patients & Methods. Following institutional review board approval, we performed a retrospective study of patients who presented to a level I trauma center with acute fractures of the thoracic and lumbar spine between 2010 and 2013; patients also had to have had an abdominal (or L1) CT scan either during the admission or in the 6 months before or after their injury. Using a picture archiving and communication (PACS) system, we generated regions of interest (ROI) of similar size in the body of L1 (excluding the cortex) and computed mean values for HU. Values derived were compared against threshold values which differentiate between osteoporosis and osteopenia - for specificity of 90%, a threshold of 110 was set; for balanced sensitivity and specificity, a threshold of <135 HU was set and for 90% sensitivity a threshold of <160 HU was set. A student's t test was used to compare the age stratified mean HU (younger than 65yrs; 65yrs and older), while Fisher's exact test was used to perform aged stratified comparisons between the proportions of patients above and below the thresholds outlined (in each of the three threshold groups). Results. A total of 124 patients were evaluated, with 74 having thoracic and 50 having lumbar fractures. Among those with thoracic fractures, there were 33patients in the younger cohort, who also had a mean BMD of 196.51HU and 41 in the older cohort, who had mean BMD of 105.90HU (p<0.001). In patients with lumbar fractures, 27 patients were in the younger cohort, with mean BMD of 192.26HU and 23 patients in the older cohort with mean BMD of 114.31HU (p<0.001). At the threshold of 110 HU, set for specificity, the magnitude of difference between the age stratified cohorts was greater in the thoracic spine (p<0.001 vs. p=0.003). At the other thresholds: 135HU (balanced for sensitivity and specificity) and 160 HU (90% sensitivity), age of 65 years or older was significantly associated with reduction in CT derived measure of BMD (p<0.001 in all cases). Discussion. This study demonstrates the relative frequency of osteoporosis in acute fractures of the thoracic and lumbar spine, and how this changes with age; it is also the first study to do this using opportunistic CT scans. There seems to be a strong association between a reduction in bone mineral density and advanced age, in patients presenting with acute fractures of the spine. This approach may save on the extra cost and additional radiation exposure that may be associated with DXA scanning; in addition, it may help provide clinicians and patients with an approach to monitor developing problems with BMD before it becomes clinically apparent, especially in younger patients

The aim of this biomechanical study was to investigate the role of the dorsal vertebral cortex in transpedicular screw fixation. Moss transpedicular screws were introduced into both pedicles of each vertebra in 25 human cadaver vertebrae. The dorsal vertebral cortex and subcortical bone corresponding to the entrance site of the screw were removed on one side and preserved on the other. Biomechanical testing showed that the mean peak pull-out strength for the inserted screws, following removal of the dorsal cortex, was 956.16 N. If the dorsal cortex was preserved, the mean peak pullout strength was 1295.64 N. The mean increase was 339.48 N (26.13%; p = 0.033). The bone mineral density correlated positively with peak pull-out strength.

Preservation of the dorsal vertebral cortex at the site of insertion of the screw offers a significant increase in peak pull-out strength. This may result from engagement by the final screw threads in the denser bone of the dorsal cortex and the underlying subcortical area. Every effort should be made to preserve the dorsal vertebral cortex during insertion of transpedicular screws.

A retrospective series of 45 cases of chronic osteomyelitis collected over a period of 14 years was histologically classified into tuberculous osteomyelitis (25) and chronic non-granulomatous osteomyelitis (20). The tuberculous osteomyelitis group was divided into three subgroups: a) typical granulomas (13 cases); b) ill-defined granulomas (seven cases), and c) suspected granulomas (five cases). An in-house polymerase chain reaction amplifying the 245 bp nucleotide sequence, and capable of detecting 10 fg of DNA of Mycobacterium tuberculosis, was used on the DNA extracted from the paraffin blocks. The polymerase chain reaction was positive in 72% of cases (18) of tuberculous osteomyelitis, but when typical cases of tuberculous osteomyelitis with confirmed granulomas were considered (13), this increased to 84.6% (11). The chronic non-granulomatous osteomyelitis group gave positive polymerase chain reaction results in 20% of the cases (4).

Our preliminary study on tuberculous osteomyelitis shows that the polymerase chain reaction can be a very useful diagnostic tool, since a good correlation was seen between typical granulomas and polymerase chain reaction with a sensitivity of 84.6% and a specificity of 80%. In addition, our study shows that tuberculous osteomyelitis can be diagnosed in formalin-fixed paraffin-embedded tissues in the absence of typical granulomas.