Is the identification of the external branch of the superior laryngeal nerve mandatory in thyroid operation? Results of a prospective randomized study

Abstract

Background: The aim of this study was to investigate the incidence of injury to the external branch of the superior laryngeal nerve (EBSLN) with 2 different surgical approaches.

Methods: From 1998 to 2000, 289 consecutive patients undergoing thyroidectomy were randomly divided into 2 groups. In group A (137 patients [215 upper pole ligations]), the superior thyroid artery was ligated after identification of the EBSLN. In group B (152 patients [244 upper pole ligations]), the superior thyroid artery's branches were ligated separately close to the gland. In all patients, a phoniatric evaluation with videostrobolaryngoscopy and spectrographic examination was performed.

Results: The 2 groups were well matched regarding age, sex, thyroid pathological findings, and type of operation. In group A, the EBSLN was not clearly identified in 11.6% of cases. Alterations of EBSLN function were absent in both groups of patients, either postoperatively or 1 and 6 months after operation. Group B showed statistically significant shorter operative time compared with that for group A.

Conclusions: Even if the EBSLN often crosses the superior thyroid pedicle, especially in large goiters, this study demonstrated that accurate distal ligation of the branches of the superior thyroid artery is a safe technique to prevent EBSLN injury.