Background: C5 palsy is a serious but poorly understood complication after posterior cervical decompression that could lead to muscle weakness, brachialgia and numbness of the upper limbs. The incidence of C5 palsy varies greatly between studies. The risk factors are inconclusive and even conflicting.
Object: To perform a systematic review on the incidence and risk factors of C5 palsy after posterior cervical decompression.
Materials and methods: Four databases, PubMed, Embase, Web of Science and Cochrane CENTRAL, were searched to identify eligible studies. Either a fixed- or a random-effects model was used to calculate the pooled odd ratio (RR) or standardized mean difference (SMD) with its 95% confidence interval (95%CI).
Results: Of the 589 pre-recruited studies, 25 were included in this study for systematic review. The pooled incidence of C5 palsy after posterior decompression was 5.8% (95%CI: 4.4-7.2%). The incidence after open-door laminoplasty, double-door laminoplasty and laminectomy was 4.5%, 3.1% and 11.3%, respectively. The significant risk factors of C5 palsy were OPLL (OR, 2.188; 95%CI, 1.307-3.665), narrower intervertebral foramen (SMD, -0.972; 95%CI, -1.398 to -0.545), laminectomy (vs. open-door laminoplasty, OR, 2.988; 95%CI, 1.298-6.876), excessive spinal cord drift (SMD, 1.289, 95%CI, 0,197-2.381) and male gender (OR, 1.54; 95%CI, 1.036-2.301).
Conclusions: The results of this systematic review suggest that patients with excessive spinal cord drift, preexisting intervertebral foramenal stenosis, OPLL, laminectomy and male gender are at high risk for postoperative C5 palsy, and risk-reduction options should be considered for such patients.