Recurrent Laryngeal Nerve Monitoring Versus Identification Alone on Post-Thyroidectomy True Vocal Fold Palsy: A Meta-Analysis

Objectives/Hypothesis: To compare by meta-analysis the effect of recurrent laryngeal nerve (RLN) monitoring versus RLN identification alone on true vocal fold palsy rates after thyroidectomy. Study Design: Systematic review and meta-analysis. Methods: A search of MEDLINE (1966-July 2008), EMBASE (1980-July 2008), Cochrane Central Register of Clinical Trials (CENTRAL), Cochrane Database of Systematic Reviews, clinicaltrials.gov, and The National Guideline Clearinghouse databases was performed. References from retrieved articles, presentation data, and correspondence with experts was also included. All authors used a detailed list of inclusion/exclusion criteria to determine articles eligible for final inclusion. Two authors independently extracted data including study criteria, methods of vocal fold function assessment, laryngeal nerve monitor type, and surgical procedure. Odds ratios (OR) were pooled using a random-effects model. Associations with patient and operative characteristics were tested in subgroups. Results: One randomized clinical trial, seven comparative trials, and 34 case series evaluating 64,699 nerves-at-risk were included. The overall incidence of true vocal fold palsy (TVFP) was 3.52% for intraoperative nerve monitoring (IONM) versus 3.12% for nerve identification alone (ID) (OR 0.93; 95% confidence interval [CI], 0.76-1.12]. No statistically significant difference in transient TVFP (2.74% IONM vs. 2.49% ID [OR 1.07, 95% CI, 0.95-1.20]), persistent TVFP (0.75% IONM vs. 0.58% ID [OR 0.99, 95% CI, 0.79-1.23]), or unintentional RLN injury (0.12% IONM vs. 0.33% ID [OR 0.50, 95% CI, 0.15-1.75]) was found. Conclusions: This meta-analysis demonstrates no statistically significant difference in the rate of true vocal fold palsy after using intraoperative neuromonitoring versus recurrent laryngeal nerve identification alone during thyroidectomy.