Intraoperative nerve monitoring in thyroid surgery—shifting current paradigms

Abstract

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.

Experience with the use of intraoperative continuous nerve monitoring in video‐assisted neck surgery and external cervical incisions

“…The usefulness of intermittent nerve monitoring has been well documented 13‐16 . CIONM overcomes the key methodological limitation inherent to intermittent nerve monitoring, which allows the nerve to be at risk in between stimulations 8,17 . In patients with CIONM, RLN stress can be identified real‐time during thyroid prolapse, Berry's ligament dehiscence, or dissection of the midline region.…”

Anatomical, functional and dynamic evidences obtained by intraoperative neuromonitoring improving the standards of thyroidectomy

“…With continuation of traction, amplitude keeps on decreasing and the increase of latency becomes evident due to the loss of myelin sheath. [ 56 ]…”

Training Courses in Laryngeal Nerve Monitoring in Thyroid and Parathyroid Surgery- The INMSG Consensus Statement

“…Intraoperative neural monitoring (IONM) is now an integral aspect of thyroid surgery in many centers. Interest in IONM, the number of institutions that perform, and societies that recommended monitored thyroidectomies have increased throughout the world in recent years (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). A recent international survey (16) of over 1,000 surgeons revealed that IONM is highly prevalent with 83% of surgeons using IONM in some or all of their cases.…”

“…The body of knowledge in IONM has also rapidly evolved in recent years with the introduction of new, less invasive monitoring devices, as well as the publication of prospective randomized clinical trials, multi-center studies, cost analyses, studies of ethical/medicolegal issues, clinical guidelines, and standards for the recurrent laryngeal nerve (RLN) and external branch of the superior laryngeal nerve (EBSLN) monitoring (1-4, 11, 17-34). Additionally, current technology enables the use of continuous-IONM (C-IONM) to analyze nerve monitoring signal loss and recovery under periodic vagus nerve (VN) stimulation and to understand the relationship between signal loss and early postoperative vocal fold palsy (5,(35)(36)(37)(38). Up-to-date structured courses are needed to introduce the clinical, legal and research implications of these developments, in order that monitoring be done at the highest optimal and most current standards.…”