Neuromonitoring and Video-assisted Thyroidectomy: a Prospective, Randomized Case-control Evaluation

Introduction: This study evaluates the role of intraoperative neuromonitoring (IONM) in video-assisted thyroidectomy (VAT) with emphasis given to the identification of recurrent laryngeal nerve (RLN) and external branch of superior laryngeal nerve (EBSLN).

Methods: The study was based on a prospectively randomized series comprising 72 standard VAT gasless approaches. In the control group (N = 36), the laryngeal nerves were identified by 30 degrees 5-mm endoscope magnification solely. The standard technique of the IONM group (N = 36) consisted of localizing and monitoring EBSLN, both vagus and RLNs, before and after thyroid resection to prove nerve integrity. Surgical outcomes were mean operative time, nerve representation, incision length, and morbidity.

Results: All procedures were performed successfully. There were no instances of equipment malfunction or interference. No permanent complications occurred in either group. The incidences of temporary RLN injury were 2.7% (1 patient) and 8.3% (3 patients) in the IONM and control group, respectively. The EBSLN was identified better in the IONM group: 83.6% versus 42% (p < 0.05). In the IONM group, a negative electromyography (EMG) response indicated an altered function of RLN and stage thyroidectomy was scheduled.

Conclusions: This is the first VAT series with a standardized IONM technique. The technical feasibility and safety of IONM in selected patients seem acceptable. Neuromonitoring during VAT is effective in providing identification and function of laryngeal nerves. IONM enables surgeons to feel more comfortable with their approach to VAT. A reduction of rates for postoperative complications could not be demonstrated in the present study. Larger series are needed for further evaluation.