Effectiveness of Intraoperative Neuromonitoring of the External Branch of the Superior Laryngeal Nerve During Thyroid Surgery

The external branch of superior laryngeal nerves(EBSLNs) are important for voice quality. Injury to this nerve during thyroid surgery can manifest as ipsilateral paralysis of the cricothyroid muscle. Clinical symptoms may include: hoarseness, breathy voice, an increase in the rate of throat clearing, vocal fatigue, or diminished vocal frequency range, especially with regards to raising pitch. The amount of EBSLNs identified intraoperatively varies from 10% to 80%, while the rate of EBSLN injury reported in the literature is between 5% and 28%, depending on different evaluation methods. Advances in intraoperative neuromonitoring techniques would allow for EBSLN identification during thyroid surgery. However, there is controversy regarding usefulness in preserving EBSLN function using nerve monitoring system. The aim of the study is to evaluate effectiveness of neuromonitoring during thyroid surgery for the preservation of EBSLNs.