Year 2021
October 2021


Abstract Title
Feasibility of Intraoperative Nerve Monitoring (IONM) in Endoscopic Thyroid Surgery



Khoo Teck Puat Hospital1

Background & Hypothesis

A major obstacle to the acceptability of scarless endoscopic thyroid surgery (SET) is the perceived absence of seamless Intraoperative Nerve Monitoring (IONM). Unlike conventional thyroidectomy, most centers performing SET do not regularly attempt confirmatory visual documentation of the recurrent laryngeal nerve due to technical difficulty and many surgeons safeguard the nerve by leaving behind a rim of thyroid tissue along the suspensory ligament. Very few studies have evaluated the feasibility of regular confirmatory visualization of the recurrent laryngeal nerves during SET.


We evaluated the role of IONM in a prospective non-randomized experimental study during the learning phase of SET. The first 25 consecutive patients undergoing Endoscopic Hemi-thyroidectomy by the Unilateral Axillary Breast approach for unilateral benign disease and nodule size < 60 mm and no previous neck/thyroid surgery underwent a feasibility evaluation. Nerve monitoring was carried out before and after visual inspection of the recurrent laryngeal nerve after creating a dissection space in the neck. A dedicated long metallic conducting hook probe was used to sound the nerve through the 5mm working port.


No case was converted. 16 out of 25 (64%) recurrent laryngeal nerves were successfully stimulated. Only 8 were visualized (32 %). 9 out of 25 RLN’s could not be stimulated or visualized inspite of dedicated dissection attempts. 12 out of 25 (48%) external laryngeal nerves were successfully stimulated. Only 2 could be visualized (8%). There were no cases of permanent voice change.

Discussion & Conclusion

IONM offers limited benefit in endoscopic thyroidectomy during its early learning stage.