An institutional experience of intraoperative neurophysiological monitoring application in robotic thyroidectomy: a retrospective case-control study

Purpose: Intraoperative neurophysiological monitoring (IONM) has been introduced in thyroid surgery to prevent injury of the recurrent laryngeal nerve (RLN). However, its effectiveness remains controversial in robotic thyroidectomy (RT). This study aimed to compare the surgical outcome of RT in patients with and without the application of I0NM. Methods: This retrospective case-control study included 100 patients who underwent total thyroidectomy via robotic bilateral axillo-breast approach in a tertiary center. A study group of 50 patients who had I0NM during RT was compared to a control group of 50 patients who underwent RT with nerve visualization alone. Results: The sex ratio [4:45 vs. 7:43, P = 0.538), mean age [39.3 ± 7.1 years vs. 37.5 ± 10.4 years, P = 0.304], and body mass index (23.1 ± 2.6 kg/m2 vs. 22.2 ± 3.9 kg/m2, P = 0.215) were comparable between the I0NM and control groups. Pathologic features including tumor size (0.8 cm vs. 0.9 cm, P = 0.283), extrathyroidal extension (58.0% vs. 24.0%, P = 0.316), lymph node metastasis (30% vs. 34%, P = 0.668), and number of lymph nodes (5.3 vs. 5.3, P = 0.668) showed no differences. There was no permanent RLN palsy, postoperative bleeding, and wound complications. Transient hypoparathyroidism was observed in 12 (24.0%) and 14 (28.0%), permanent hypoparathyroidism in 0 (0%) and 1 (2.0%), and transient RLN palsy was observed in 3 (6.0%) and 3 (6.0%), respectively. Conclusion: We did not demonstrate a clear advantage of I0NM in RT. Controversies regarding the effectiveness of I0NM is not closed.