Selective Intraoperative Nerve Monitoring for High-risk Thyroidectomy

Abstract

Aim: To compare early postoperative voice outcome between visual nerve identification (VNI) and selective intraoperative nerve monitoring (IONM) in high-risk thyroidectomy operations. Materials and methods: All patients undergoing high-risk thyroidectomy operations for thyroid cancer, thyrotoxicosis, and reoperative completion between January 2018 and June 2019 were retrospectively evaluated. Demographic information, type of operation (hemithyroidectomy/ reoperation/total thyroidectomy), and nature of thyroid disease were assessed. Comparisons were made between VNI and IONM groups on postoperative clinical hoarseness, endoscopically confirmed recurrent laryngeal nerve (RLN) injury, and the operating time between the VNI group and IONM group. Subgroup analyses were also carried out. Results: Fifty-eight patients with 94 nerves at risk were included in the analysis. Forty-seven patients (81.0%) underwent thyroidectomy with VNI, while 11 patients (19.0%) had IONM. Thirty-six procedures (62.1%) were total thyroidectomy and 22 (37.9%) were hemithyroidectomy. Six patients received concomitant cervical lymph node dissection (10.3%). Indications for surgery included 43 thyroid carcinoma (74.1%) and 15 thyrotoxicosis (25.9%); and of which, 22 (37.9%) were reoperations. Demographics were comparable between the assessed groups. Postoperative clinical hoarseness per nerve at risk was significantly lower in the IONM group compared to the VNI group (0 vs 19.4%, p = 0.046). Endoscopically confirmed recurrent laryngeal nerve injury in IONM group was apparently lower, without statistical significance (0 vs 10.4% p = 0.176). Conclusion:Our data demonstrated that the use of IONM in selected high-risk thyroidectomy surgery significantly reduced early postoperative clinical hoarseness compared to the routine VNI. Clinical significance: The use of IONM in selected high-risk thyroidectomy may improve early postoperative voice outcome.