Intraoperatıve Nerve Monıtorıng Durıng Thyroıdectomy Can Reduce the Injury to the External Branch of the Superıor Laryngeal Nerve Durıng Superıor Thyroıd Pole Dıssectıon: A Prospective Randomized Study

ABSTRACT Background The primary aim of this study was to characterize the prevalence of external branch of the superior laryngeal nerve (EBSLN) injury with and without the use of intraoperative neuromonitoring (IONM) and identify factors associated with injury. Methods Patients referred to our clinic for thyroidectomy between June 2015 and June 2016 were prospectively randomized into two groups (single‐blinded): in Group 1, IONM was used during upper pole dissection only for the management of the recurrent laryngeal nerve (RLN); in Group 2, IONM was used for both RLN and EBSLN management. After thyroidectomy completion in all patients, cricothyroid muscle (CTM) EMG was performed. Results EBSLN injury was significantly higher in Group 1 (15.4 vs. 2.1% of NAR, p < 0.001). EBSLN injury was detected in 23 (9.4%) of 245 Friedman type 1, in 7 (18.9%) of 37 Friedman type 2, and in 3 (3.2%) of 94 Friedman type 3 nerves. Conclusion EBSLN injury is often a transection injury associated with permanent EBSLN dysfunction. Use of IONM facilitates the prevention of EBSLN injury.