The value of neurostimulation and intraoperative nerve monitoring of inferior laryngeal nerve in thyroid surgery

To determine the accuracy of neurostimulation with laryngeal palpation (NSLP) and intraoperative neuromonitoring (IONM) to predict the postoperative function of recurrent laryngeal nerve (RLN) in thyroid surgery. Historical cohort study. A retrospective case control study with 993 patients. The control group (799 patients with 1450 nerves at risk) included patients who underwent NSLP and the case group (194 patients with 354 nerves at risk) consisted of those who underwent NSLP in association with IONM. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and accuracy were calculated for NSLP and IONM, with nerve palsy as the target outcome. A significant difference in nerve injury between the case and the control group ( P = 0.31) was not observed. The presence or absence of laryngeal twitch (LT) ( P < 0.0001) and the acoustic response to electrical stimulation ( P = 0.003) were significantly associated with nerve function at the end of the surgery. Our results indicate that NSLP is a safe and reliable intraoperative method of RLN monitoring. Moreover our data confirm that IONM is not a helpful tool to reduce the rate of palsy in thyroid surgery.