Intraoperative nerve monitoring in thyroid surgery—shifting current paradigms

Over the past two decades, intraoperative neural monitoring (IONM) has matured into a powerful risk minimization tool. Meta-analyses of studies, most of which were limited by poor study designs and the sole use of intermittent nerve stimulation, failed to demonstrate superiority of IONM over anatomic recurrent laryngeal nerve (RLN) dissection in the absence of IONM. With the advent of continuous IONM (CIONM), intraoperative nerve electromyographic tracings, registered almost in real time during the operation, accurately predict postoperative vocal fold function when International Neural Monitoring Study Group quality standards are adhered to. CIONM aids in avoiding permanent traction-related nerve injury by urging surgeons to reverse harmful surgical maneuvers. CIONM also forms an integral part in the surgical concept of staged thyroidectomy. Delaying completion surgery on the other side until nerve function has recovered mitigates the risk of bilateral vocal fold palsy. CIONM has greatly furthered our understanding of functional RLN injury, enabling conception of effective risk minimization strategies tailored to the individual patient. The review summarizes the advances of continuous IONM technology that caused a quantum leap in risk minimization for thyroid surgery, shifting current paradigms.