Application of Continuous and Intermittent Intraoperative Nerve Monitoring in Thyroid Surgery

Whether continuous intraoperative nerve monitoring (C-IONM) can further reduce the incidence of recurrent laryngeal nerve injury compared with intermittent intraoperative nerve monitoring (I-IONM) in high-risk thyroid surgery is still controversial. This observational study aimed to evaluate the incidence of vocal cord paralysis (VCP) in high-risk thyroid surgeries performed with I-IONM and C-IONM.

High-risk thyroid surgical patients operated with I-IONM or C-IONM by the same group of surgeons in the thyroid surgery department of our institution between January 2014 and February 2018 were analyzed. Differences in the incidence rates of temporary and permanent VCP between the two groups were compared. A P-value < 0.05 was considered statistically significant.

A total of 344 patients who underwent high-risk thyroid surgery (550 nerves at risk [NARs]) were observed, with 238 patients (374 NARs) operated with I-IONM and 106 patients (173 NARs) operated with C-IONM. The incidence of temporary and permanent VCP was 1.9% (7/374) and 0.8% (3/374) in the I-IONM group and 1.2% (2/173) and 0% (0/173) in the C-IONM group, respectively, showing no statistical difference (P = 0.726 and P = 0.555). The incidence rate of impending recurrent laryngeal nerve injuries successfully prevented in the C-IONM group was 5.2% (9/173).

Both I-IONM and C-IONM are equally safe and effective in high-risk thyroid surgery. C-IONM can help predict impending recurrent laryngeal nerve injury in real time and has a good warning feature, thereby minimizing critical maneuvers in high-risk thyroid surgery.