Supramaximal neurostimulation with laryngeal palpation to predict postoperative vocal fold mobility.

Abstract

Recurrent laryngeal nerve (RLN) injury during thyroidectomy or parathyroidectomy is a challenging issue and causes significant morbidity. We adopted the supramaximal stimulation protocol for neurostimulation with laryngeal palpation (NSLP) and tried to evaluate the predictive values of supramaximal NSLP for immediate postoperative vocal fold (VF) mobility. Prospective cohort study. Prospectively, 293 patients who underwent thyroid and parathyroid surgery and 542 RLNs at risk were enrolled in this study. During NSLP, the current was escalated to 3 mA until definite laryngeal twitch was observed. Immediate postoperative VF mobility was evaluated using flexible laryngoscopy. Diagnostic accuracy of NSLP is calculated according to cutoff values of minimal current intensity (1 mA, 1.5 mA, and 2 mA). At 2mA, sensitivity was 81.82%, specificity 100%, positive predictive value 100%, and negative predictive value 99.62%. Supramaximal NSLP might be a simple and reliable method to predict immediate postoperative VF mobility in open thyroid and parathyroid surgeries when intraoperative neuromonitoring is unavailable. 4. Laryngoscope, 126:2863-2868, 2016.