Effect of anterior cervical decompression fusion at different cervical segments on C5 nerve root palsy

Objective: This study aimed to investigate the effect of anterior cervical decompression fusion at different cervical segments on C5 nerve root palsy. Methods: A total of 78 patients who received anterior cervical decompression and bone graft fusion due to cervical disease and ossification of the posterior longitudinal ligament of the spine between March 2009 and August 2013 were retrospectively reviewed. Patients were divided into 2 groups: In Group A, patients underwent 1- or 2-segment decompression, and those in Group B underwent 3-or 4-segment decompression. The Japanese Orthopedic Association (JOA) scoring system was used to evaluate the clinical efficacy. The preoperative and postoperative cervical curvature indexes (CCI) and cervical lordosis angle (Cobb angle) were measured. Results: The incidence of C5 nerve root palsy was 2% in Group A and 15.8% in Group B, showing a significant difference (P<0.05). In addition, the postoperative CCI change rate was 18.0 +/- 16.6% in Group B, which was significantly higher than in Group A (11.5 +/- 7.9%), and the postoperative cervical Cobb angle and CCI increased markedly in Group B, as compared to those before surgery (P<0.05). The JOA score was comparable between two groups before and after surgery (P> 0.05). Conclusion: Decompression fusion at several segments may increase the intervertebral disc gap and significantly change postoperative cervical curvature, which is an important cause of C5 nerve root injury.