Correlative study of nerve root palsy and cervical posterior decompression laminectomy and internal fixation

This study investigates the probable causes of nerve root palsy through the retrospective study of pre- and postoperative cervical curvature change for patients with cervical spondylosis and incidences of nerve root palsy. A consecutive series of 91 patients with cervical compressive myelopathy treated by laminectomy and internal fixation were reviewed. Nerve root palsy developed in 21 of 91 patients (23%) (group A). The other 70 patients, 41 men and 29 women, were chosen as controls (group B). A neutral lateral cervical spine radiograph was taken of all patients. The overall curvature of the cervical spine, the cervical curvature index, and the change rate were measured and compared.The pre- and postoperative change rate of cervical curvatures in groups A and B was 19.17+/-7.62 and 18.03+/-7.62, respectively. The difference was not statistically significant (P>.05). The pre- and postoperative cervical curvature index change rate in groups A and B was 17.52+/-3.46 and 12.43+/-4.12, respectively. There were statistically significant differences between the 2 groups (P<. 05). This indicated the cervical alignment of patients in group A was changed greatly by traction during operation.In this study, we found that tethering the nerve root caused C5 palsy, but excessive intraoperative traction and the use of internal fixation may be one of the most important reasons for this. The cervical curvature index change rate reflected both a change in cervical height and a change in the overall cervical curvature. It is more sensitive in reflecting the degree of cervical traction and the change of the cervical alignment.