Effect of partial foraminotomy after laminoplasty surgery on preventing C5 nerve root palsy

Abstract

Objective To investigate clinical curative effect of partial foraminotomy after C4,5 ossification of posterior longitudinal ligament (OPLL) on preventing C5 nerve root palsy. Methods A total of 155 patients with OPLL were treated with expansion open-door laminoplasty (EOLP) between January 2008 and October 2012, including 75 male patients and 80 female patients, with average age of 54.5 (ranging from 38 to 75). Among them, 90 cases took EOLP (open team), and 65 cases took EOLP and C4,5 partial foraminotomy (incision team). Clinical curative effect and imaging evaluation were used in 8 weeks and 12 months after operation. JOA scores, JOA scores improvement rate, C5 nerve root palsy occurrence rate, neurological function of patients with C5 nerve root palsy and the prognosis, cervical curvature index, opening angular variation, backward drift distance of anterior margin and posterior margin of the spinal cord were evaluated after 8 weeks and 1 year after the surgery. Results The operation time was 90-140 min, with the average time of 110±14 min; mean bleeding volume was 160±45 ml (ranging from 100 to 250 ml); follow-up visit time was 15.4 months on average (ranging from 12 to 18 months). JOA score and improvement rate after 8 weeks and 1 year of the operation have no statistical significance. The C5 nerve root palsy occurrence rate in open team was 8.89% (8/90), while that in incision team was 4.62% (3/65). The difference of two groups has statistical significance. C5 nerve root palsy all happened in laminar opening side. Comparison of cervical curvature index of two groups before the operation and after 8 weeks of the operation and inter-group comparison have no statistical significance. The difference between laminar opening angle after 1 year of the operation and laminar opening angle after 8 weeks has no statistical significance. The difference of backward drift distance of anterior margin of the spinal cord at different time after the operation and inter-group difference have no statistical significance. The difference in backward drift distance of posterior margin of the spinal cord between 1 year after the operation and 8 weeks after the operation has no statistical significance. Conclusion Treating OPLL with EOLP and C4,5 partial foraminotomy can reduce occurrence rate of C5 nerve root palsy, but has no significant influence on JOA score improvement rate. Key words: Cervical vertebrae; Foraminotomy; Decompression, surgical; Comparative study