Selective recurrent laryngeal nerve stimulation using a penetrating electrode array in the feline model

• Published in: The Laryngoscope 2018-07, Vol.128 (7), p.1606-1614
• Main Authors: Haidar, Yarah M., Sahyouni, Ronald, Moshtaghi, Omid, Wang, Beverly Y., Djalilian, Hamid R., Middlebrooks, John C., Verma, Sunil P., Lin, Harrison W.
• Format: Article
• Language: English
• Subjects: Animals; Cats; Disease Models, Animal; Electric Stimulation - instrumentation; Electric Stimulation Therapy; Electrodes, Implanted; Electromyography; Experiments; Laryngeal Muscles - physiology; multichannel electrode array; Muscle Contraction - physiology; Nerve Fibers - physiology; posterior cricoarytenoid; posterior cricoarytenoid muscle; Recurrent laryngeal nerve; Recurrent Laryngeal Nerve - anatomy & histology; Recurrent Laryngeal Nerve - pathology; Recurrent Laryngeal Nerve - physiology; recurrent laryngeal nerve implant; Recurrent Laryngeal Nerve Injuries - complications; Recurrent Laryngeal Nerve Injuries - pathology; Recurrent Laryngeal Nerve Injuries - physiopathology; recurrent laryngeal nerve stimulation; Vocal Cord Paralysis - etiology; Vocal Cord Paralysis - therapy
• ISSN: 0023-852X; 1531-4995
• DOI: 10.1002/lary.26969

Objectives/Hypothesis Laryngeal muscles (LMs) are controlled by the recurrent laryngeal nerve (RLN), injury of which can result in vocal fold (VF) paralysis (VFP). We aimed to introduce a bioelectric approach to selective stimulation of LMs and graded muscle contraction responses. Study Design Acute experiments in cats. Methods The study included six anesthetized cats. In four cats, a multichannel penetrating microelectrode array (MEA) was placed into an uninjured RLN. For RLN injury experiments, one cat received a standardized hemostat‐crush injury, and one cat received a transection‐reapproximation injury 4 months prior to testing. In each experiment, three LMs (thyroarytenoid, posterior cricoarytenoid, and cricothyroid muscles) were monitored with an electromyographic (EMG) nerve integrity monitoring system. Electrical current pulses were delivered to each stimulating channel individually. Elicited EMG voltage outputs were recorded for each muscle. Direct videolaryngoscopy was performed for visualization of VF movement. Results Stimulation through individual channels led to selective activation of restricted nerve populations, resulting in selective contraction of individual LMs. Increasing current levels resulted in rising EMG voltage responses. Typically, activation of individual muscles was successfully achieved via single placement of the MEA by selection of appropriate stimulation channels. VF abduction was predominantly observed on videolaryngoscopy. Nerve histology confirmed injury in cases of RLN crush and transection experiments. Conclusions We demonstrated the ability of a penetrating MEA to selectively stimulate restricted fiber populations within the feline RLN and selectively elicit contractions of discrete LMs in both acute and injury‐model experiments, suggesting a potential role for intraneural MEA implantation in VFP management. Level of Evidence NA. Laryngoscope, 128:1606–1614, 2018