The Value of Identifying External Branch of Superior Laryngeal Nerve in Post-Operative Voice Performance: A Randomized Clinical Trial

Background: Injury to the external branch of the superior laryngeal nerve (EBSLN) results in deterioration of postoperative voice performance. The aim of this study was to asses the impact of exploring and identifying the EBSLN during thyroidectomy in reducing nerve injury and consequently preserved voice performance. Methods: Ninety patients, in 2 groups, underwent a thyroidectomy and a total of 122 upper poles were dissected. After 2 to 4 weeks, patients with voice complaints were evaluated by electromyography of cricothyroid muscle. Results: There were 4 unilateral injuries (10%) in the explored group whereas in the non-explored group (9 unilateral and 2 bilateral) (P = 0.28), there were 11 (22%). A total of 7.4% of 54 upper thyroid poles injuries were observed in the explored group whereas 16% injuries of 68 upper thyroid poles in the non-explored group (P = 0.12). Conclusions: The injury to the EBSLN decreased when upper thyroid pole dissection was accompanied with nerve exploring. The EBSLN should be explored and identified during the thyroidectomy because it makes a noticeable change in the postoperative voice performance.