Adaptation of Continuous Intraoperative Vagus Nerve Stimulation for Monitoring of Recurrent Laryngeal Nerve During Minimally Invasive Esophagectomy.

INTRODUCTION

Esophagectomy has risk of recurrent laryngeal nerve (RLN) injury. Conventional nerve monitoring has been used to help identify and protect the RLN. A new concept of continuous intraoperative nerve monitoring (CIONM) by stimulation of the ipsilateral vagus nerve has been used in thyroidectomy. The current report describes adapting the CIONM method for use in video-assisted thoracoscopic (VATS) esophagectomy.

MATERIALS AND METHODS

The nerve monitor employed is NIM 3.0 with automatic periodic stimulation (Medtronics Inc., USA). Patient is intubated with NIM contact-reinforced EMG endotracheal tube (Medtronics Inc., USA). The operation starts with a left lower neck incision, and the stimulating electrode is secured around the left vagus nerve. The patient is then turned to the left lateral position for VATS esophagectomy. CIONM of the left RLN is achieved by regular stimulation of the left vagus nerve, and intact nerve conduction is detected by the electromyography (EMG) of the left vocalis muscle. The alarm is set to activate when EMG amplitude reduces by 50% or latency prolongs by 10%.

RESULTS

Initial experience of ten cases showed that a mean time of 35 min was required to complete the electrode insertion in the neck. There was one event in which there was more than 50% reduction of EMG amplitude that persisted but the patient had no vocal cord paralysis after operation. In another patient, the EMG reduced by 75% and persisted. The patient had temporary vocal cord paralysis.

CONCLUSION

CIONM is feasible during VATS esophagectomy and can alert the surgeon of imminent injury to the RLNs, thereby preventing permanent injury.