Percutaneous probe stimulation for intraoperative neuromonitoring in total endoscopic thyroidectomy: A preliminary experience.

BACKGROUND

The purpose of this study was to investigate the feasibility and value of using intraoperative neuromonitoring (IONM) performed via percutaneous probe stimulation during total endoscopic thyroidectomy.

METHODS

This study prospectively enrolled a series of 132 consecutive patients with 156 recurrent laryngeal nerves (RLNs) at risk who received total endoscopic thyroidectomy performed via bilateral breast approach using standardized IONM. The stimulation probe was introduced into the working space by percutaneous puncture. During lateral thyroid dissection, the proximal RLN was periodically stimulated to monitor adverse electromyography (EMG) changes. Preoperative and postoperative vocal cord mobility was routinely examined with laryngofiberoscopy.

RESULTS

All IONMs were successfully performed via percutaneous probe stimulation with no morbidity or scarring in the neck. Twelve nerves (7.7%) showed significant changes in EMG (amplitude reduction, 50% to 90% from baseline EMG) during the lateral thyroid dissection. Compression near the inferior thyroid artery (70%) and traction near the Berry's ligament (30%) were the most common causative mechanisms, and modification of the surgical maneuver resulted in partial recovery of the EMG changes (amplitude reduction, 10% to 80% before wound closure). Of the 12 nerves with adverse EMG changes (final amplitude reduction, 65% to 80%), 8 nerves showed temporary (3 months or less) vocal cord palsy. No cases of permanent vocal cord palsy occurred in this series.

CONCLUSION

Percutaneous probe stimulation is a simple, effective, and safe method of performing IONM in total endoscopic thyroidectomy when the operating space is limited. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1001-1007, 2017.