Risk factors for C5 palsy following the posterior spinal process-splitting laminoplasty for cervical ossification of the posterior longitudinal ligament: a case control study

Nan Li; Kaiping Zhao; Yan An; Kai Yan; Bo Liu; Da He

doi:10.21037/atm-22-1730

Risk factors for C₅ palsy following the posterior spinal process-splitting laminoplasty for cervical ossification of the posterior longitudinal ligament: a case control study

Ann Transl Med. 2022 Jun;10(11):634. doi: 10.21037/atm-22-1730.

Authors

Nan Li^#¹, Kaiping Zhao^#², Yan An¹, Kai Yan¹, Bo Liu¹, Da He¹

Affiliations

¹ Department of Spinal Surgery, Beijing Jishuitan Hospital & the Fourth Clinical Medical College of Peking University, Beijing, China.
² Department of Medical Record Management and Statistics, Beijing Jishuitan Hospital & the Fourth Clinical Medical College of Peking University, Beijing, China.

^# Contributed equally.

Abstract

Background: Postoperative C₅ palsy is a common complication of laminoplasty for cervical ossification of the posterior longitudinal ligament (C-OPLL), although there are several hypotheses regarding its etiology, the exact pathomechanism for this undesirable event remain unclear. The aim of this study was to review clinical and imaging findings in patients with C₅ palsy and to propose potential risk factors for this complication.

Methods: A total of 220 consecutive patients who had undergone posterior spinal process-splitting laminoplasty (pSPSL) for C-OPLL between January 2018 and December 2019 were included in this study. Postoperative C₅ palsy was defined as deltoid muscle weakness of a grade ≤3 in manual muscle test (MMT). These patients were divided into two groups based on the postoperative development of C₅ palsy: patients with C₅ palsy (group A) and those without C₅ palsy (group B). The clinical and imaging covariates evaluated were age, sex, OPLL type, K-line, foraminal stenosis, gutter malposition, and preoperative spinal cord signal change. Logistic regression was used to analyze the independent risk factors for C₅ palsy.

Results: In total, 211 patients (18 in group A and 193 in group B) were enrolled in this study, and the incidence of C₅ palsy was 8.53%. Sixteen patients had a MMT of grade 3 and two had an MMT of grade ≤2. During the follow-up period (mean duration: 25.10±6.67 months), the MMT grade rose to 5 in 16 patients, 4 in one patient, and 3 in one patient. Multivariate analysis revealed that malposition of the bony gutter [odds ratio (OR) 11.073, 95% confidence interval (CI): 3.411, 35.948; P<0.001] and C_4/5 intervertebral foramen stenosis (OR 8.455, 95% CI: 2.559, 27.936; P<0.001) were independent risk factors for C₅ palsy.

Conclusions: The incidence of C₅ palsy was 8.53% among patients undergoing pSPSL for C-OPLL. Gutter malposition and C_4/5 intervertebral foramen stenosis were identified as risk factors for this complication.

Keywords: Cervical vertebrae; complication; laminoplasty; nerve root palsy; ossification of the posterior longitudinal ligament (OPLL).