Standards for Intraoperative Neuromonitoring in Thyroid Operations

After the introduction of intraoperative neural monitoring (IONM) of the recurrent laryngeal nerve (RLN) in clinical thyroid practice almost 16 years ago, the procedure has expanded rapidly with an area-wide spread in Asia, Europe, and USA. While the visual nerve presentation with the eye or the magnifying glass technique is capable of assessing the anatomical continuity of the RLN, IONM additionally allows a functional analysis that has a high correlation, i.e., prediction of postoperative vocal motility. Although the predictive value of the IONM is much higher (>97%) in the case of an intact signal than in the case of a signal failure (40%–70%), the prediction is also unequally higher than the visual-anatomical assessment of the nerve. Thus, IONM can be used as a basis for an intraoperative decision-making of a 1-side or 2-side procedure to avoid bilateral RLN palsy in a bilateral procedure. A precondition for the safe application of IONM is the perfect knowledge of the technology and technique, the routine execution of preoperative and postoperative laryngoscopy, the strict standardization of the neurostimulation (electromyography documentation of the vagal nerve stimulation before and after resection), and an adequate management of technically or operationally caused incidents (i.e., systematic application of troubleshooting algorithms). The following review provides a synopsis of the experiences of the Korean Intraoperative Neural Monitoring Society (KINMoS) for the correct use of IONM.