Risk factors for C5 nerve root palsy following posterior cervical spinal canal expansion and reconstruction: a systematic review and meta-analysis

C5 nerve root palsy is the most common complication following posterior cervical spinal canal expansion and reconstruction, significantly impacting patients’ quality of life. Although several systematic reviews and meta-analyses have explored the risk factors of C5 nerve root palsy, inconsistencies remain in key conclusions such as the role of age and C4-5 intervertebral foramen stenosis, and new clinical evidence published in recent years has not been integrated. This meta-analysis aims to evaluate the incidence and risk factors of C5 nerve root palsy after posterior cervical spinal canal expansion and reconstruction, providing a more precise and generalizable basis for clinical screening of high-risk patients and formulation of preventive interventions. Case-control trials on C5 nerve root palsy following posterior cervical spinal canal expansion and reconstruction were retrieved from PubMed, Embase, Cochrane Library, Web of Science, CNKI, and Wanfang databases. The search period spanned from each database’s inception to November 2025. Search strategies were tailored to each database’s characteristics. We extracted the basic characteristics of included studies, the incidence of C5 nerve root palsy symptoms, and associated risk factors. Included studies underwent risk of bias assessment and quality evaluation. Meta-analysis was performed using Stata 18.0 to assess the incidence and risk factors of C5 nerve root palsy symptoms. (1) Seventeen studies were included, involving a total sample size of 2,995 cases. The incidence of axial symptoms was 14% (95%CI: 0.10, 0.17), with 15 studies meeting higher quality standards; (2) Meta-analysis results indicated that advanced age (OR = 2.71, 95%CI: 1.53 ~ 3.88)、male gender (OR = 0.36, 95%CI: 0.03 ~ 0.68)、narrowing of the C4-5 intervertebral foramen width (OR=-0.61, 95%CI: -0.84 ~ 0.38)、changes in cervical curvature (OR = 2.88, 95%CI: 1.90 ~ 3.86)、increased spinal cord retraction distance (OR = 0.72, 95%CI: 0.57 ~ 0.87) and high signal intensity on T2-weighted MRI at the C4-5 spinal cord segment (OR = 0.93, 95%CI: 0.16 ~ 1.69) were identified as independent risk factors for C5 nerve root paralysis symptoms. Advanced age, male gender, narrowing of the C4-5 intervertebral foramen width, changes in cervical curvature, increased spinal cord retraction distance, and high signal intensity on T2-weighted MRI at the C4-5 spinal cord segment are independent risk factors for C5 nerve root palsy symptoms. Patients with these high-risk factors require close follow-up and timely intervention to reduce the incidence of C5 nerve root palsy symptoms and improve their quality of life.