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The morphologic changes and signal intensity of the spinal cord on preoperative magnetic resonance images were correlated with postoperative outcomes in 74 patients undergoing decompressive cervical surgery for compressive myelopathy. The transverse area of the spinal cord on T1-weighted images at the level of maximum compression was closely correlated with the severity of myelopathy, duration of disease, and recovery rate as determined by the Japanese Orthopaedic Association score. In patients with ossification of the posterior longitudinal ligament or cervical spondylotic myelopathy, the increased intramedullary T2-weighted magnetic resonance imaging signal at the site of maximal cord compression and duration of disease significantly influenced the rate of recovery. A multiple regression equation was then developed with these three variables to predict surgical outcomes.

Study design Radiologic study for patients with athetoid cerebral palsy (CP), and a biomechanical study using the finite-element model (FEM). Objectives To understand the lumbar disorders of athetoid CP patients and the etiology based on the results from the FEM study. Summary of background data Cervical spondylotic myelopathy is a well-identified spinal disorder associated with cerebral palsy, especially in athetoid type. One can rationalize that the athetoid involuntary trunk movement may induce stress-related lumbar disorders. Until now, very few investigations have been conducted on lumbar disorders that could occur in patients with CP. Methods Sixty-one cases with athetoid cerebral palsy were clinically reviewed. Radiographs of the lumbar spine in 30 cases with low back pain were taken. From these radiographs, the incidence of lumbar spondylolysis and endplate lesion was analyzed. The biomechanical study was conducted using a three-dimensional FEM of the ligamentous lumbar spine. Axial compression of 400 N was applied to simulate preload on the spine during the standing position followed with 10.6 Nm moment to simulate extension and axial rotation. The combined motion of extension and axial rotation was also simulated. During supine position, pure extension and rotation were simulated, and no preload was applied. The von Mises stresses were computed at the pars interarticularis at the each level and compared for different motions. Results Among the 61 patients, 41 complained of symptoms such as low back and leg pain. Thirty of these 41 patients gave their consents to undergo radiographic evaluation. Twenty-eight of the 30 patients (93.3%) showed stress-related disorders such as the spondylolysis and/or vertebral endplate lesions. Spondylolysis was found in 18 of the 30 patients (60.0%). Spondylolysis was observed at the multiple levels in 4 patients involving two levels in 2 cases and three levels in the other 2 cases. Vertebral endplate lesions (deformity) were seen in 26 (86.7%) of the 30 patients. Overall, the lesions (deformity) were found in 109 of 330 endplates (33.0%) out of all lumbar endplates in the 30 patients. The FEM based results showed that stresses at pars interarticularis of L5 were the highest of all levels in all loading modes, with or without preload. However, compared with the extension or axial rotation alone modes, the combined motion of extension and rotation showed higher stresses at the pars interarticularis. Conclusions The athetoid involuntary movements in CP patients may cause stress-related lumbar disorders. Especially, combined extension and rotation due to the involuntary trunk motion may contribute to the high incidence of spondylolysis.

Transverse areas of the spinal canal, the dural tube and the spinal cord of the cervical spine of normal adults and patients with cervical spondylotic myelopathy (CSM) were analyzed by magnetic resonance imaging (MRI).Correlations of the results of MRI to clarify the pathogenesis of CSM.Relationships between the area of the spinal cord and that of the dural tube or the spinal canal have been reported, but there is no report to compare the relationships among the three in patients with CSM and normal adults.T1-weighted MR images of the cervical spine of 96 normal adults and 74 patients with CSM were evaluated by measuring the transverse areas of the three structures mentioned above in the axial plane.In normal adults, the maximal transverse area of the spinal cord was 85.8 mm2 at C4/5 and the minimal transverse areas of the dural tube and the spinal canal were 186.0 mm2 at C5/6 and 236.1 mm2 at C4, respectively. At the unaffected level of C3, the ratio of the canal to the spinal cord was significantly higher in CSM patients than in age-matched normal adults. The transverse area of the spinal cord and the ratio at the maximal compression level showed significant correlations with the severity of neurological symptoms.These results suggest that the narrow area and high ratio of the spinal canal to the spinal cord are responsible for a static factor in CSM.