Preservation of the nonrecurrent laryngeal nerve using intraoperative nerve monitoring during endoscopic thyroidectomy.

A 40-year-old woman underwent right lobe thyroidectomy for thyroid nodules that increased in size from 17 mm to 33.5 mm within 1 year. Identification of arteria lusoria using computed tomography suggested the presence of a right nonrecurrent laryngeal nerve (RNRLN). Endoscopic thyroidectomy was performed under general anesthesia. The right vagal nerve was first identified between the common carotid artery and jugular vein. A positive response was confirmed via intraoperative neuromonitoring (IONM), implying that the RNRLN did not branch from the central side of the stimulated point of the vagal nerve. The RNRLN was confirmed using IONM around the middle to lower pole of the right thyroid gland. The right thyroid lobe was successfully removed, with meticulous preservation of the RNRLN. The motion of the vocal cord, examined by an ear-nose-throat doctor postoperatively, was intact. We demonstrated the efficacy of IONM in patients with RNRLN who underwent endoscopic thyroidectomy.