Unilateral spondylolysis and the presence of facet joint tropism.

STUDY DESIGN: Retrospective review of the CT scans performed in a group of patients examined for a possible spondylolysis. OBJECTIVE: To investigate whether there is an association between unilateral spondylolysis and facet joint tropism. SUMMARY OF BACKGROUND DATA: Spondylolysis is a fatigue fracture of the pars interarticularis of great importance in sports injury. The demonstration of a unilateral spondylolysis is important because there is a potential for full healing if the athletic activity is modified, whereas bilateral spondylolysis frequently leads to established nonunion. Coronally orientated facet joints are known to predispose to spondylolysis by increasing the point loading of the pars interarticularis. The importance of this finding has not been investigated in unilateral spondylolysis. METHODS: A review of patients with low back pain and a possible diagnosis of spondylolysis who were investigated with multislice CT was performed. The coronal orientation of the facet joints at L4/5 and L5/S1 was measured and comparison was done between those with and without a spondylolysis. RESULTS: The coronal angle of 140 facet joints in 35 patients was recorded. Of 35 patients, 23 had a spondylolysis which was unilateral in 12 patients. The facet joint angle was significantly more coronally orientated in the presence of a spondylolysis when compared with an intact pars (means, 53° and 43°, respectively; P < 0.01). In the presence of a unilateral spondylolysis, the facet joint was significantly more coronally orientated on the side of the spondylolysis (means, 52° and 45°, respectively; P < 0.01). CONCLUSION.: This study is the first investigation of facet joint anatomy in unilateral spondylolysis. Asymmetric facet joints do increase the force through one side of the spine, with a unilateral spondylolysis occurring on the side of the more coronally orientated facet joint.

Do chronic medical conditions increase the risk of eating disorder? A cross-sectional investigation of eating pathology in adolescent females with scoliosis and diabetes.

PURPOSE: To investigate levels of eating pathology in female adolescents diagnosed with a chronic condition causing appearance change (adolescent-onset idiopathic scoliosis), a chronic condition affecting nutritional behavior (insulin-dependent diabetes mellitus), and healthy age-matched controls. METHOD: Cross-sectional comparison of 192 females aged 11-19 years; 76 individuals diagnosed with scoliosis, 40 diagnosed with diabetes, and 76 control participants. Disordered eating behavior was quantified using the Eating Disorder Examination Questionnaire, and weight and body mass index (weight [kg]/height [m(2)]) measurements were taken for each participant. RESULTS: The scoliosis group weighed less and had lower BMI scores (p < .001) than control participants. Of the participants with scoliosis, 25% were severely underweight, but only two met the behavioral criteria for anorexia nervosa; in others no association with disordered eating behaviour was found. Eating disorders were significantly more common (p < .05) in the diabetes participants than in the control group, with 27.5% of the group classified as having bulimia or binge eating disorder. All those classified as overweight or obese in the diabetes group were classified as pathological in terms of eating behavior. CONCLUSIONS: The relationship between scoliosis and low body mass is a concern but is not a result of an eating disorder. Etiological mechanisms remain unclear and require further investigation. In the diabetes participants, bulimia and binge eating may prejudice effective condition management. Implications for successful adaptation, treatment intervention, and future research are discussed.

Primary bone tumours of the spine: a 42-year survey from the Leeds Regional Bone Tumour Registry.

We conducted a review of the Leeds Regional Bone Tumour Registry for primary bone tumours of the spine since establishment in 1958 until year 2000. To analyse the incidence of primary tumours of the spine and to record the site of occurrence, sex distribution, survival and pathology of these tumours. Primary tumours of the spine are particularly rare, accounting for between 4 and 13% of published series of primary bone tumours. The Leeds Bone Tumour Registry was reviewed and a total of 2,750 cases of bone tumours and tumour-like cases were analysed. Consultants in orthopaedic surgery, neurosurgery, oncology and pathology in North and West Yorkshire and Humberside contribute to the Registry. Primary bone tumours of the osseous spine constitute only 126 of the 2,750 cases (4.6%). Chordoma was the most frequent tumour in the cervical and sacral regions, while the most common diagnosis overall was multiple myeloma and plasmacytoma. Osteosarcoma ranked third. The mean age of presentation was 42 years and pain was the most common presenting symptom, occurring in 95% of malignant and 76% of benign tumours. Neurological involvement occurred in 52% of malignant tumours and usually meant a poor prognosis. The establishment of Bone Tumour Registries is the only way that sufficient data on large numbers of these rare tumours can be accumulated to provide a valuable and otherwise unavailable source of information for research, education and clinical follow-up.

A dynamic study of thoracolumbar burst fractures.

BACKGROUND: The degree of canal stenosis following a thoracolumbar burst fracture is sometimes used as an indication for decompressive surgery. This study was performed to test the hypothesis that the final resting positions of the bone fragments seen on computed tomography imaging are not representative of the dynamic canal occlusion and associated neurological damage that occurs during the fracture event. METHODS: A drop-weight method was used to create burst fractures in bovine spinal segments devoid of a spinal cord. During impact, dynamic measurements were made with use of transducers to measure pressure in a synthetic spinal cord material, and a high-speed video camera filmed the inside of the spinal canal. A corresponding finite element model was created to determine the effect of the spinal cord on the dynamics of the bone fragment. RESULTS: The high-speed video clearly showed the fragments of bone being projected from the vertebral body into the spinal canal before being recoiled, by the action of the posterior longitudinal ligament and intervertebral disc attachments, to their final resting position. The pressure measurements in the synthetic spinal cord showed a peak in canal pressure during impact. There was poor concordance between the extent of postimpact occlusion of the canal as seen on the computed tomography images and the maximum amount of occlusion that occurred at the moment of impact. The finite element model showed that the presence of the cord would reduce the maximum dynamic level of canal occlusion at high fragment velocities. The cord would also provide an additional mechanism by which the fragment would be recoiled back toward the vertebral body. CONCLUSIONS: A burst fracture is a dynamic event, with the maximum canal occlusion and maximum cord compression occurring at the moment of impact. These transient occurrences are poorly related to the final level of occlusion as demonstrated on computed tomography scans.