Use of the neurostimulator in thyroidectomy procedures: comparison between vagal and recurrent laryngeal nerve stimulation

BACKGROUND: Recurrent laryngeal nerve (RLN) dysfunction represents one of the most feared complications of thyroid surgery, with significant impacts on patients' quality of life due to the potential paralysis of the vocal cords. Although nerve transection is rare, functional loss - non-structural and invisible to the human eye - is the primary cause of this complication. Intraoperative nerve monitoring (IONM), introduced more than 50 years ago and significantly improved over the past decade, represents a crucial tool for preventing this outcome. METHODS: This retrospective observational study involves patients undergoing total or partial thyroidectomy at a specialized center in Italy from 2023 to the present and aims to compare the predictive effectiveness of vagus nerve (VN) stimulation versus RLN stimulation, evaluating three techniques (C-IONM, I-IONM, and No-IONM). All patients were monitored using a NIM system (NIM Avalanche SI2), with pre- and postoperative laryngoscopic evaluation. RESULTS: Among 378 patients undergoing thyroid surgery, no significant differences in baseline demographics were observed among groups. The absence of intraoperative neuromonitoring was associated with a significantly higher risk of permanent vocal cord paralysis compared with I-IONM (OR 4.84, P=0.012). C-IONM showed no cases of permanent paralysis and was associated with significantly shorter operative time and reduced length of hospital stay compared with both intermittent monitoring and no monitoring. CONCLUSIONS: I-IONM significantly improves neurological safety in thyroid surgery. C-IONM provides the most favorable overall profile, combining comparable safety with improved operative efficiency and postoperative recovery, and represents a promising strategy for further optimization of surgical outcomes.