A new anchor electrode design for continuous neuromonitoring of the recurrent laryngeal nerve by vagal nerve stimulations.

ABSTRACT

PURPOSE: Intraoperative neuromonitoring has the limitation that the recurrent laryngeal nerve (RLN) is still at risk for damage between two stimulations with a handheld bipolar stimulation electrode. The purpose of this study was to establish the vagal anchor electrode for real-time monitoring of the RLN in surgical routine and to be alerted to imminent nerve failure by electromyography (EMG) signal analysis whereby the nerve damage becomes reversible. PATIENTS AND METHODS: This fully implantable electrode has been used in addition to a conventional handheld bipolar stimulation electrode during thyroid surgery on 45 consecutive patients (78 nerves at risk) stratified to low- and high-risk groups. The signal analysis was performed as real-time audio/video feedback by the use of a new multichannel EMG system. RESULTS: No complications were attributable to the use of the anchor electrode. The mean delay to place the anchor electrode was 1.45 min, whereas the mean stimulation time of the vagus nerve was 38 min. Stable and repeatable signals were evocable in all cases with one exception. No permanent RLN paralyses occurred in this study. CONCLUSIONS: The vagal anchor electrode is safe and easy to use. It allows continuous neuromonitoring without any threats. The new technique will provide more security, especially during preparation steps on the RLN that are difficult for the surgeon.