Routine recurrent laryngeal nerve (RLN) identification is mandatory and constitutes the gold standard in thyroid surgery. Intraoperative nerve monitoring (IONM) has been introduced as complementary tool for visualizing RLN allowing its evaluation and prediction of function. Aim of this study is to establish how routine IONM utilization can affect learning curve (LC) in young surgeons approaching thyroidectomy.

Patients undergoing total-thyroidectomy performed by surgical residents in their LC in two academic hospitals, were divided into two groups: Group A, including 150 thyroidectomies performed without IONM by 3 different residents (A1-A2-A3), and Group B, including 150 procedures with routine use of intermittent IONM, by other 3 different residents(B1-B2-B3). LC was measured by comparing operative time (OT), its stabilization during the development of LC, intraoperative and postoperative complication rate for each series of procedures.

LC was achieved after 30 procedures, in both groups, without differences due to the IONM use. Similarly, there were no significant differences among the two groups, and between subgroups independently matched, for both OT and complications, even when comparing RLN palsy. Direct nerve visualization and IONM assessment rates were comparable in all groups, no bilateral RLN palsy (transient/permanent) were reported. No case of interrupted procedure to unilateral lobectomy, due to evidence of RLN injury, was reported.

The present study demonstrates that IONM use, despite requiring a specific training in experienced surgeons, does not particularly affect the LC of residents approaching thyroid surgery, and for this reason its routine use should be strongly encouraged even for trainees and surgical residents.