Neuromonitoring in endoscopic and robotic thyroidectomy

Abstract

Intraoperative neuromonitoring (IONM) has proven effective for intraoperative verification of RLN function in the conventional thyroid surgery. However, no studies have performed a systematic evidence-based assessment of this novel health technology in endoscopic and robotic thyroidectomy. Evidence-based criteria were used in a systematic review of relevant literature for years 2000-2015. Four electronic databases (CENTRAL, MEDLINE, Cochrane and EMBASE) were used to retrieve relevant reports published from January 1, 2000 to September 1, 2016. The search terms included "endoscopic thyroidectomy", "robotic thyroidectomy", "IONM", "continuous IONM (CIONM)", "neural monitoring", "recurrent laryngeal nerve monitoring", and "superior laryngeal monitoring". The following data were retrieved from eligible studies of patients undergoing endoscopic or robotic thyroidectomy: objective of study, design and setting of study, population, intervention examined, quality of data, follow-up and dropout rate, risk of bias, and outcomes assessed. Of 160 studies retrieved, only 9 (5%) studies used IONM. Eight studies reported 522 nerve at risk (NAR) with IONM. Only three were prospective randomized studies. Reports of IONM endoscopic and robotic procedures included their use for re-surgery and use in both benign and malignant cases. None of the IONM endoscopic procedures involved bilateral palsy. Two studies reported the use of a staged strategy. The rates of recurrent laryngeal palsy were 0-3.6% for transient and 0-0.4% for permanent. Only 30% of the studies performed vagus nerve stimulation, and only 25% performed superior laryngeal nerve monitoring. In addition to the use of IONM as an assistive technology for navigating the anatomy in challenging procedures such as endoscopic and robotic thyroidectomy, IONM has potential use as a routine adjunct to the conventional video-assisted nerve identification in thyroidectomy.

Analysis of neuromonitoring signal loss during retroauricular versus conventional thyroidectomy

“…To reduce possible bias, we excluded patients with preoperative VCP and only included those with clear R1. In the review by Dionigi et al, the VN stimulation rate was not as high as 30%, as reported previously . We suspect that this may have been because of the additional burden on the surgeon to perform extra steps to identify VN.…”

“…We also described surgical techniques that may be associated with LOS and analyzed the postoperative VCP rates. Recently, Dionigi et al published a systemic review on the use of IONM in endoscopic and robotic thyroidectomy . In this review, eight studies with a total of 522 NAR with IONM were described.…”

“…In this review, eight studies with a total of 522 NAR with IONM were described. However, there were no comparisons between the intraoperative IONM results and surgical techniques associated with LOS . IONM results present a good opportunity to compare intraoperative surgical techniques and their associated LOS that suggest RLN injury.…”

“…Robotic and endoscopic thyroidectomy via a retroauricular approach (RAT) has been performed since 2011, and several reports and publications have demonstrated its safety and feasibility with excellent cosmetic results . These remote‐access thyroidectomies have become increasingly popular, with >70% robotic and endoscopic thyroidectomy cases being performed in some Korean medical centers …”

Opportunities and challenges of intermittent and continuous intraoperative neural monitoring in thyroid surgery

“…A recent review of the literature found that IONM was employed in no more than 9 (5%) of 160 studies dealing with endoscopic and robotic surgery (34). Only 3 (30%) of these 9 studies also entailed stimulation of the VN, and only 2 studies also stimulation of the EBSLN.…”