Nerve Conduction Studies of the Larynx: Porcine Model and Human Application

There is a paucity of information in the literature about how electromyography (EMG) with nerve conduction studies (NCS) can be utilized in the field of neurolaryngology. The goal of this study was two-part: (1) to identify the NCS test parameters that best reflect underlying neurolaryngeal pathophysiology in a porcine model, and (2) to determine if comparable NCS parameters can be used to assess clinical laryngeal denervation injuries in patients.

Yukatan minipigs underwent general anesthesia with EMG and recurrent laryngeal NCS assessment. Recurrent laryngeal nerve (RLN) transection injury and uninjured RLN cases were included to determine NCS neuropathologic and normative findings, respectively. Our porcine analytic model was then applied to a clinical scenario of seven patients with RLN injury.

The porcine model was able to differentiate and characterize normative and neuropathologic NCS changes. Clinical outcomes suggest that RLN NCS can be performed clinically and is overall well tolerated by in patients. Findings may serve as a useful tool to differentiate normal nerve function, neuropraxia, axonotmesis, and irreversible RLN injuries.

This novel study is the first to demonstrate the feasibility and applicability of EMG with NCS in the evaluation of vocal fold function in a porcine model in addition to the clinical setting. Further studies are needed to better understand the clinical utility and predictive value in recovery of vocal fold paralysis.