Expansive laminoplasty by sagittal splitting of the spinous process for cervical myelopathy: correlation of clinical results with morphological changes in the cervical spine.

Morphological changes in the cervical spine were evaluated using radiography in 140 patients with cervical myelopathy who underwent expansive laminoplasty by sagittal splitting of the spinous process. We assessed the influence of these observed changes on the postoperative clinical results. The mean follow-up period was 33 +/- 19 months. Intervertebral body union occurred in 18%, and interlaminal union in 80% of the patients. The factors influencing the bony union in these were not identified. Bony union did not significantly influence the clinical results. There were changes in cervical alignment in 29 (21%) patients after the operation. Correlation between the spinal curvature and the clinical results was the strongest for the sigmoid-type curvature. The number of patients in whom preoperative ROM was maintained was only 8 (7%). The range of cervical spine motion decreased by approximately 50%, and there was no correlation with the clinical results. The surgical method described in the current study for compression myelopathy was associated with postoperative morphological changes and decreased ROM in the cervical spine, but nonetheless provided good postoperative results unless extreme morphological abnormalities occurred. This surgical technique was safe and gave satisfactory results in patients with preoperative morphological abnormalities in the cervical spine.