The recurrent laryngeal nerve and the external branch of the superior laryngeal nerve (EBSLN) in the TAM and CTM, respectively, can be monitored with vagus nerve stimulation. With 100% sensitivity and 98 percent specificity, a significant muscle response (greater than 100 V) is 100% predictive of maintained laryngeal mobility, while the absence of a muscle response is 70% predictive of vocal fold paralysis. Only ipsilateral to the stimulus is a significant thyroarytenoid muscle response recorded, with a shorter latency on the right side.

One of the most common complications of thyroid surgery is recurrent laryngeal or inferior laryngeal nerve injury, which can be fatal, especially in the case of bilateral nerve lesions. Less severe clinical characteristics of damage to the external branch of the superior laryngeal nerve include lethargy and monotonous voice, loss of high-pitched sounds, and singing voice, which is particularly problematic for voice professionals. Surface electrodes on thev endotracheal tube or monopolar or bipolar electrodes implanted directly into the laryngeal muscles are being used for intraoperative recurrent laryngeal nerve monitoring. There are two types of nerve stimulation: stimulation of the recurrent laryngeal nerve or the external branch of the superior laryngeal nerve, and stimulation of the vagus nerve.