Posterior Laminectomy and Lateral Mass Screw Fixation With 1-2 Levels Laminoplasty for the Treatment of Cervical Spondylotic Myelopathy.

Abstract

Study design: Retrospective, observational study.

Objective: This study aimed to evaluate the clinical efficacy of cervical posterior laminectomy with lateral mass screw internal fixation combined with 1-2 levels of laminoplasty in patients with severe complex cervical spondylotic myelopathy.

Summary of background data: In this single-center retrospective observational study, data collected from 15 patients who underwent modified cervical posterior laminectomy with lateral mass screw internal fixation (modified PLF group) were compared with those from 45 patients who underwent standard cervical posterior laminectomy with lateral mass screw internal fixation (PLF group) during the same period.

Methods: The cervical curvature, Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS), neck disability index (NDI), Odom's grade, and development of C5 nerve palsy were compared preoperatively and postoperatively. A power analysis was conducted to determine the sample size required to detect clinically significant differences between the groups. Based on an expected effect size of 0.5, a significance level (α) of 0.05, and a power (1-β) of 80%, the analysis indicated that a minimum of 60 patients per group would be needed. The mean follow-up period was 3.5 years.

Results: A significant reduction in the extent of cervical kyphosis (P<0.05) was observed at the last follow-up in both groups. There were no significant differences in the JOA score, VAS, and NDI, all of which significantly improved in both groups. The rates of excellent and good Odom's grading (100% and 88.89% in the modified PLF and PLF groups, respectively) and the incidence of C5 nerve palsy (0% and 11.11% in the modified PLF and PLF groups, respectively) were significantly different between the 2 groups (P<0.05). The power analysis confirmed that the study was adequately powered to detect significant differences in cervical curvature and clinical outcomes, although the smaller sample size of the modified PLF group (n=15) may have limited the ability to detect smaller but clinically meaningful differences in secondary outcomes.

Conclusions: Modified cervical posterior laminectomy with lateral mass screw internal fixation achieved improved clinical outcomes after medium-to-long-term follow-up in patients with severe and complex cervical spondylotic myelopathy. It can stabilize the cervical spine, fully decompress the spinal canal, and prevent excessive backward drifting of the cervical spinal cord, thereby reducing cervical spinal cord injury and C5 nerve palsy.