VOLUME 54 NO 05 MAY 2020

Neuromonitoring in Thyroid Surgery

Thyroid surgery can cause temporary or permanent damage to the recurrent laryngeal (RLN) and superior laryngeal nerve (SLN) causing hoarseness, impaired vocal phonation, dysphonia, dysphagia and even aspiration dyspnea. Bilateral damage to the RLN can be life-threatening leading to airway obstruction. Damage to these nerves depends on the type of disease (benign or malignant), extent of thyroid resection (lobectomy vs. total thyroidectomy), type of resection (first surgery or reoperation) and the training and experience of the surgeon. Surgical exposure and identification of both nerves during surgery is the gold standard in avoiding damage. For the past ten years refinement in neuromonitoring (NM) has helped introduced electrodes in the endotracheal tube in contact with the vocal cords to monitor the functional viability of both nerves during thyroid surgery. Throughout this time NM of the RLN/SNL during thyroid surgery has allowed visual identification and exposure of both nerves, allowing recording affording a valid legal protection in case of damage. NM localizes the exact location in case of injury and determines if the injury is reversible by repairing a damage nerve. NM allows young surgeons and surgeons-in-training to approach thyroid surgery more safely. NM can also help identify anatomic variants present in less than 5% of all patients. NM has become and asset in difficult thyroid dissections, substernal goiters, redo surgery and bloody thyroidectomy. Electric nerve testing at the end of the thyroidectomy can serve for postoperative prognostication of nerve function. Detecting nerve injury intraoperatively aids in staging bilateral lobectomies to avoid bilateral vocal cord paralysis and tracheotomy. It is estimated that NM should be included as standard of care of thyroid surgery in children and adults. NM studies are not based in class 1 evidence randomized clinical trials, but in evidence 2 and 3 studies. NM is actually the only way to verify the functional integrity of the RLN and SLN during thyroid procedures. As recurrent laryngeal nerve injury is one of the most common causes of medicolegal litigation after thyroid and parathyroid surgery securing the nerve is an increasing demand in these procedures.

1- Zheng S, Xu Z, Wei Y, Zeng M, He J: Effect of intraoperative neuromonitoring on recurrent laryngeal nerve palsy rates after thyroid surgery--a meta-analysis. J Formos Med Assoc. 112(8):463-72, 2013
2- Barczynski M, Konturek A, Pragacz K, Papier A, Stopa M, Nowak W: Intraoperative nerve monitoring can reduce prevalence of recurrent laryngeal nerve injury in thyroid reoperations: results of a retrospective cohort study. World J Surg. 38(3):599-606, 2014
3- Deniwar A, Kandil E, Randolph G: Electrophysiological neural monitoring of the laryngeal nerves in thyroid surgery: review of the current literature. Gland Surg. 4(5):368-75, 2015
4- Wong KP, Mak KL, Wong CK, Lang BH: Systematic review and meta-analysis on intra-operative neuro-monitoring in high-risk thyroidectomy. Int J Surg. 38:21-30, 2017
5- Henry BM, Graves MJ, Vikse J, et al: The current state of intermittent intraoperative neural monitoring for prevention of recurrent laryngeal nerve injury during thyroidectomy: a PRISMA-compliant systematic review of overlapping meta-analyses. Langenbecks Arch Surg. 402(4):663-673, 2017
6- Wojtczak B, Sutkowski K, Kaliszewski K, Barczynski M, Bolanowski M: Thyroid reoperation using intraoperative neuromonitoring. Endocrine. 58(3):458-466, 2017
7- Cirocchi R, Arezzo A, D'Andrea V, et al: Intraoperative neuromonitoring versus visual nerve identification for prevention of recurrent laryngeal nerve injury in adults undergoing thyroid surgery. Cochrane Database Syst Rev. 2019 Jan 19;1:CD012483. doi:10.1002/14651858.CD012483.pub2.
8- Zhang D, Pino A, Caruso E, Dionigi G, Sun H: Neural monitoring in thyroid surgery is here to stay. Gland Surg. 9(Suppl 1):S43-S46, 2020


*Edited by: Humberto Lugo-Vicente, MD, FACS, FAAP
P.O. Box 10426, Caparra Heights Station, San Juan, Puerto Rico 00922-0426
Tel (787)-999-9450 Fax (787)-720-6103 E-mail: TITOLUGO@COQUI.NET
® Copyright Office of the Library of Congress 1997

Journal Club
Pediatric Surgery Update ISSN 1089-7739
Last updated: June 2020