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

Abstract

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. 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. 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. 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.