Clinical anatomy for external branch of the superior laryngeal nerve during thyroid surgery by intraoperative neuromonitoring / 中华普通外科杂志

ABSTRACT

Objective To evaluate the mechanism of external branch of the superior laryngeal nerve (EBSLN) injury during thyroid surgery as showed by intraoperative neuromonitoring.Methods 70 patients with 109 nerves at risk were enrolled in this study from March 2011 to October 2011.A positive signal is determined by observing contractions of the cricothyroid muscle.The relationship between EBSLN and the upper pole of the thyroid or the inferior constrictor muscle was studied.Results 108 nerves (99.1％) were located successfully,42 of which were visualized (38.9％).55 nerves (50.9％) crossed the superior thyroid artery more than 1 cm apart,while the other 53 nerves (49.1％) went less than 1 cm including 24 nerves(more than 0.5 cm,less than 1 cm) and 29 nerves (less than 0.5 cm) or coursed below the superior pole of the thyroid.The rate of the latter type was significantly elevated in patients with the top to botton diameter of the gland more than 5 cm.One patient suffered from impairing in the production of high tones postoperatively.Conclusions Intraoperative neuromonitoring is useful and helpful in providing instructive information for operations by locating EBSLN.