Recurrent laryngeal nerve electrophysiologic monitoring in thyroid surgery: the standard of care?

Reports in the literature suggest that the rate of transient and permanent vocal fold immobility (VFI) after thyroid surgery is 4% to 7% and 1% to 4%. The intraoperative use of nerve integrity monitors has been advocated to reduce the incidence of VFI during thyroid surgery. The purpose of this study was to compare postoperative VFI after unmonitored and monitored thyroid surgical procedures. The charts of 136 consecutive patients who underwent thyroid surgery from 1998 to 2003 were retrospectively surveyed. Fifty-four patients had total thyroidectomies, bringing the total recurrent laryngeal nerves (RLNs) dissected to 190. Three of 190 (1.6%) and 7 of 190 (3.7%) RLNs dissected had permanent and transient vocal fold dysfunction. Overall, 107 RLNs were unmonitored compared with 83 RLNs that were monitored. Unmonitored and monitored RLNs had a 4 of 83 (4.8%) versus 3 of 107 (2.8%) rate of transient VFI (P > 0.05). Unmonitored and monitored RLNs had a 1 of 107 (0.9%) versus 2 of 83 (2.4%) rate of permanent VFD (P > 0.05). Electrophysiologic RLN monitoring was not demonstrated in this study to reduce the incidence of transient or permanent VFI after thyroid surgery. Electrophysiologic RLN integrity does not always translate into clinical postoperative vocal fold mobility. Electrophysiologic RLN monitoring may support that the RLN was not severed in the patient with postoperative VFI.