What is the role of intraoperative nerve monitoring in thyroidectomy?

Updated: May 08, 2018
  • Author: Neerav Goyal, MD, MPH; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Some controversy still remains with regard to the use of intraoperative recurrent laryngeal nerve monitoring. Although strong anatomic knowledge is a prerequisite to any surgery, the use of intraoperative nerve monitoring allows for an intraoperative assessment of nerve function prior to removing the gland, immediately after removing the gland, and just prior to closure of the surgical site. The use of recurrent laryngeal nerve monitoring has been described since the 1970s and has evolved from intramuscular electrodes to the currently used endotracheal tubes, which have integrated surface electrodes that contact the vocal cords. [16]

Opponents to nerve monitoring cite the increased cost and set up in the operating room, as well as the risk of false positives and negatives. They also note that nerve monitoring does not reduce the rate of RLN palsy. [17]

However, studies show that while intraoperative nerve monitoring may not have a significant difference in reducing nerve injury, the presence of monitoring can be used to predict how well the nerve functions postoperatively. Choby et al describes normative values for in-situ nerve stimulation pre and post thyroidectomy. [18] Donnellan et al further describes prospective nerve stimulation thresholds and compares thresholds seen in patients with normal and abnormal vocal cord function. They conclude that there is an association between lower (≤0.5mA) stimulation thresholds and normal vocal cord function. [19]

This can have an impact on surgical management of patients undergoing total thyroidectomy for a benign condition, should one nerve not stimulate well during the case. [20]


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