Multimodal Novel Recurrent Laryngeal Nerve Monitoring Techniques in Anterior Cervical Spine Surgery: Initial...

Injury to the recurrent laryngeal nerve (RLN) during anterior cervical spine surgery is an uncommon yet impactful sequela. This study evaluates the feasibility and intraoperative behavior of laryngeal adductor reflex (LAR) and motor-evoked potentials with vocalis recordings (MEP-VC) during anterior cervical spine surgery. LAR and MEP-VC were employed for 13 patients undergoing anterior cervical spine surgery. LAR alerts were issued when clinically correlated reductions in amplitude, typically ≥20% in previously stable, non-habituating recordings, and/or temporal dispersion of the LAR waveform occurred. MEP-VC alerts were issued for a ≥50% isolated decrease in amplitude or any amplitude reduction that occurred concurrently with an LAR amplitude decline. LAR alerts were observed in five surgeries, with four showing recovery to baseline. In one case, with no LAR recovery, this patient demonstrated post-operative hoarseness. Conversely, another case showed persistent MEP-VC deterioration, despite LAR recovery following the intervention. This patient exhibited right vocal fold paralysis, diagnosed with incomplete glottic closure by an otolaryngologist. All other patients exhibited no RLN deficits post-surgery. Our proof-of-concept study demonstrates the feasibility of LAR and MEP-VC monitoring and suggests that these modalities may provide physiologically relevant information regarding RLN function during anterior cervical spine surgery.