Recent Advances in Analysis and Management of Loss of Signal During Monitored Thyroidectomy

Abstract

Injury to the recurrent laryngeal nerve (RLN) in thyroid surgery can cause vocal cord paralysis, which interferes with the voice and can potentially interfere with breathing. A major development in the past decade is the increasing use of intraoperative neural monitoring (IONM) to identify the RLN adjunct to the standard practice of visual identification. Surgeons can use IONM for real-time evaluation of the laryngeal electromyography (EMG) response, which represents the functional status of the RLN. In the case of a partial or total loss of EMG signal (LOS) indicating that RLN stress or injury has occurred, the surgeon can also evaluate the surgical maneuver that produced the impending or actual RLN injury. By elucidating the mechanism of RLN injury and the surgical pitfalls, IONM can help surgeons to evaluate and improve their surgical techniques, predict recovery and other outcomes, and plan intraoperative and postoperative management. However, the widespread use of IONM in thyroid surgery has revealed the need to develop reliable strategies for cases in which a LOS occurs on the first side of a planned total thyroidectomy. Additionally, the thyroid surgeon must be able to identify false LOS and LOS recovery to avoid unnecessary staged surgery. Therefore, reliable guidelines for intraoperative analysis and management of LOS are needed to assist surgeons in the clinical decision-making process. This article reviews recent advances in analysis and management of LOS during monitored thyroidectomy.