The Application of Intermittent Intraoperative Neuromonitoring (I-IONM) and Continuous Intraoperative Neuromonitoring (C-IONM) During Thyroid Surgery: A Single-Center Study

Abstract

Background: The application of intermittent intraoperative neuromonitoring (I-IONM) and continuous intraoperative neuromonitoring (C-IONM) has been widely accepted to improve surgical outcomes after thyroid surgery. This observational study aimed to evaluate the impact of vocal cord paralysis (VCP) in thyroid surgery conducted with I-IONM and C-IONM. Materials and Methods: From January 2018 to December 2022, 147 patients operated on with I-IONM and C-IONM for thyroid surgery were analyzed. Variations in the rates of the occurrence of temporary and permanent vocal cord paralysis between the two groups were compared. A p-value < 0.05 was considered statistically significant. Results: In total, 147 patients were eligible for inclusion in the study. Of these, 96 (65%) patients underwent thyroid surgery with I-IONM, 52 patients (35%) underwent surgery with C-IONM by a single surgeon. The percentage of temporary VCP was 4.1% (4 patients) in the I-IONM group; no patients had permanent VCP. In the C-IONM group, two patients (3.9%) had permanent vocal cord paralysis, and temporary vocal cord paralysis was observed in other two patients (3.9%), who recovered their nerve function after speech therapy. No statistically significant differences were found in the two groups. Conclusions: In our study, both I-IONM and C-IONM proved effective in predicting VCP, and no significant differences were observed between the two techniques in our series.

Keywords: continuous intraoperative neuromonitoring (C-IONM); intraoperative neuromonitoring (I-IONM); nerve monitoring; recurrent laryngeal nerve (RLN) palsy; thyroidectomy; vocal cord paralysis (VCP).

Figure 1

The anatomy of the recurrent laryngeal nerve and the superior laryngeal nerve.