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Abstract

Introduction:

Intraoperative nerve monitoring (IONM) has been introduced as an adjunct to visual identification of the recurrent laryngeal nerve, allowing for mapping of the nerve before it is visually identified, confirmation of visual identification of the nerve including its anatomical variants (ramified nerve, nonrecurrent nerve), and most importantly intraoperative prognostication of postoperative neural function. Standardized approach to IONM is mandatory to assure reliability and reproducibility of this technology. The aim of this video is to present an update on utility of this emerging technology in different clinical settings encountered during thyroid operations.

Materials and Methods:

IONM in thyroid surgery is currently available in three distinct formats: intermittent IONM (i-IONM), continuous IONM (c-IONM), and monitoring of the external branch of the superior laryngeal nerve (ebsln-IONM).

Results:

Although i-IONM can identify nerve injury once it happened, the c-IONM technology has a potential to identify an impending neural injury and prevent nerve damage before it happens by alerting the surgeon and prompting change in surgical maneuvers. The ebsln-IONM is relied on evaluation of cricothyroid muscle twitch (present in all patients) and electromyographic curve traced by the monitor using surface tube electrodes within the vocal folds that present in the majority but not all individuals (70%–80% of patients using standard EMG tubes) or approaching to 100% of patients (using NIM TriVantage tubes). The ebsln-IONM has a potential to increase the rate of the EBSLN's identification, diminish prevalence of neural damage, and decrease prevalence of postoperative voice impairment that has been repeatedly supported by recently published data.

Conclusions:

The role of IONM in its currently available formats is to provide real-time information on the status of nerve function during dissection that can decrease the risk of neural injury and improve voice preservation postoperatively.

No competing financial interests exist.

Runtime of video: 11 mins 3 secs

This video is part of the IAES 2019/WCS 2019 program, August 11–15, 2019, Kraków, Poland.