The neuromonitoring of the external branch of the superior laryngeal nerve in Micooli's endoscopic thyroidectomy

Abstract

Objective To evaluate the intraoperative neuromonitoring of the external branch of the superior laryngeal nerve (EBSLN) during Micooli's endoscopic thyroidectomy in order to avoid nerve injury.Methods In this study,36 patients with 56 nerves at risk were enrolled from February 2011 to September 2011.A positive signal is determined by observing contractions of the cricothyroid muscle to locate the EBSLN.The relationship between EBSLN and the upper pole of the thyroid or the inferior constrictor muscle was studied.The VHI-10 table was used for evaluation pre- and postoperatively. Results All 56 nerves were located successfully,26 nerves(46.4％ ) crossed the superior thyroid artery more than 1 cm apart from the upper pole of the thyroid gland,while the other 30 nerves(53.6％ ) did less than 1 cm.In cases where the diameter was longer than 5 cm,the nerves crossed the artery at less than 1.0 cm from the upper pole in 73％ cases(P =0.006).There was no significant difference between VHI-10 results before and after surgery (P ＞ 0.05). Conclusions Intraoperative neuromonitoring is useful and helpful in avoiding nerve injury by locating EBSLN. Key words: Thyroidectomy; Endoscopy; Extemal branch of the superior laryngeal nerve; Injury