Intraoperative recurrent laryngeal nerve monitoring in thyroid surgery: is it really useful?

The aim of this study was to evaluate the ability of intraoperative recurrent laryngeal nerve monitoring to predict the postoperative functional outcome and the potential role of this technique in reducing the postoperative nerve palsy rate.

Between June 2007 and December 2011, 1693 consecutive patients who underwent thyroidectomy by a single surgical team were evaluated. We compared patients who have had a neuromonitoring and patients who have undergone surgery with the only visualization. Patients in which NIM was not utilized (Group A) were 942 against the others 751 (group B).

In group A there were 28 recurrent laryngeal nerve injuries (2.97%) of which 21 were transients (2.22%) and 7 were permanents (0.74%). In group B there were 20 recurrent laryngeal nerve injuries (2.66%) of which 14 (1.86%) transients and 6 (0.8%) permanents. Differences between the two groups were not statistically significative.

The technique of intraoperative neuromonitoring in thyroid surgery is safe and reliable in excluding postoperative recurrent laryngeal nerve palsy; it has high accuracy, specificity, sensitivity and negative predictive value. Neuromonitoring is useful to identify the recurrent laryngeal nerve and it can be a useful adjunctive technique for reassuring surgeons of the functional integrity of the nerve but it does not decrease the incidence of injuries compared with visualization alone. Its application can be particularly recommended for high-risk thyroidectomies.