Intraoperative Neuromonitoring for Anterior Cervical Spine Surgery: What Is the Evidence?

ABSTRACT

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: The goal of this study was to (i) assess the risk of neurological injury after anterior cervical spine surgery (ACSS) with and without intraoperative neuromonitoring (ION) and (ii) evaluate differences in the sensitivity and specificity of ION for ACSS. SUMMARY OF BACKGROUND DATA Although ION is used to detect impending neurological injuries in deformity surgery, it's utility in ACSS remains controversial. METHODS: A systematic search of multiple medical reference databases was conducted for studies on ION use for ACSS. Studies that included posterior cervical surgery were excluded. Meta-analysis was performed using the random-effects model for heterogeneity. Outcome measure was postoperative neurological injury. RESULTS: The search yielded 10 studies totaling 26,357 patients. The weighted risk of neurological injury after ACSS was 0.64% (0.23-1.25). The weighted risk of neurological injury was 0.20% (0.05-0.47) for ACDFs compared with 1.02% (0.10-2.88) for corpectomies. For ACDFs, there was no difference in the risk of neurological injury with or without ION (odds ratio, 0.726; confidence interval, CI, 0.287-1.833; P = 0.498). The pooled sensitivities and specificities of ION for ACSS are 71% (CI 48%-87%) and 98% (CI 92%-100%), respectively. Unimodal ION has a higher specificity than multimodal ION [unimodal 99% (CI 97%-100%), multimodal 92% (CI 81%-96%), P = 0.0218]. There was no statistically significant difference in sensitivities between unimodal and multimodal [68% vs. 88%, respectively, P = 0.949]. CONCLUSION: The risk of neurological injury after ACSS is low although procedures involving a corpectomy may carry a higher risk. For ACDFs, there is no difference in the risk of neurological injury with or without ION use. Unimodal ION has a higher specificity than multimodal ION and may minimize "subclinical" intraoperative alerts in ACSS. LEVEL OF EVIDENCE 3.