Neural monitoring during ultrasound-guided radiofrequency ablation of thyroid nodules

Abstract

Background Intraoperative neurological monitoring is important in locating and assessing nerves during surgery. This study aimed to investigate the feasibility of neural monitoring during ultrasound-guided radiofrequency ablation (RFA) of thyroid nodules. Methods From February 2019 to August 2019, 16 patients (age, 42.8 ± 15.9 years; range, 17–74 years) with benign thyroid nodules who underwent ultrasound-guided RFA with neural monitoring in Zhongshan Hospital, Xiamen University, were included. A neuromonitoring system stimulated the vagus nerve to obtain electromyographic (EMG) signals and predict the function of recurrent laryngeal nerves (RLNs) during RFA. The hydrodissection technique was used to protect the RLN area. Thyroid nodules were treated with the moving-shot technique. The EMG signal value results were recorded and analyzed. All patients underwent laryngoscopic investigation 1 day after the procedure. Results Twenty vagus nerves were stimulated preprocedure and postprocedure, and the EMG signals were successfully recorded (100%). The mean initial (before ablation) and final (final ablation) vagus nerve amplitudes were 612.7 ± 130.4 μV (range, 455–882 μV) and 592.7 ± 127.3 μV (range, 410–817 μV), respectively. Based on the EMG signals, all 20 RLNs were judged to be in good condition, consistent with the postprocedure laryngoscopic results. The maximum lesion size and volume at 6 months after RFA were significantly lesser than those at baseline (p < 0.05). The volume reduction rate was 68.5% ± 21.5% (range, 13.0–97.3%). Cosmetic and symptom scores were significantly lower than those at baseline. No complications from neural monitoring occurred. Conclusions Neural monitoring during ultrasound-guided RFA of thyroid nodules is feasible to predict RLN function.

Keywords

• radiofrequency ablation
• neural monitoring
• thyroid nodule
• recurrent laryngeal nerve
• complication