Acute prediction of laryngeal outcome during thyroid surgery by electromyographic laryngeal monitoring.

BACKGROUND The purpose of this study was to evaluate the contribution of laryngeal intraoperative nerve monitoring (IONM) during thyroidectomy in predicting postoperative laryngeal mobility. METHODS Between 2009 and 2012, 127 patients underwent thyroidectomy, during which 216 recurrent laryngeal nerves were stimulated with suprathreshold stimulations. Laryngeal mobility was examined through direct laryngoscopy. Statistical analysis was performed to determine specificity, sensitivity, negative predictive value (NPV), positive predictive value (PPV), and a threshold value in order to define a intraoperative diagnostic test. RESULTS Nine patients had a unilateral laryngeal palsy. No bilateral laryngeal palsy was observed. The threshold value to assure the postoperative laryngeal mobility is 280 μV. For this value, specificity was 94.06%, sensitivity 100%, NPV 100%, and PPV 47.83%. CONCLUSION Laryngeal IONM can predict a favorable outcome of laryngeal mobility in cases in which the response exceeds 280 μV. Under this value, the risk of palsy is about 50% suggesting a staged surgery.