Comparison between Intramuscular Multichannel Electrodes and Supramysial Multichannel Electrodes via EMG Measurements for Potential Use as Larynx Stimulation Electrodes: In Vivo Animal Analysis

An Endoscopic Cap Electrode for Posterior Cricoarythenoid Muscle Stimulation in a Porcine Model

OBJECTIVE

Laryngeal pacing (LP) is a highly anticipated therapeutic option for patients suffering from bilateral vocal fold paralysis with synkinesis. Identification of candidate patients requires confirmation of a stimulable posterior cricoidarythenoid muscle (PCA) by neuromuscular electrical stimulation (NMES). A silicone endoscopic cap electrode (ECE50) was designed to be operated as an endoscopic extension tip for selective PCA stimulation and confirmation of a glottic opening movement in a setting comparable to a gastroscopy procedure.

METHODS

A porcine animal model (n = 6) was applied to develop and test endoscopic cap prototypes in general anesthesia and sedation at a biomedical research center. Two ENT endoscopy experts evaluated and refined the cap design and performance in regard to procedure safety, endoscope handling, accessibility of the PCA by the transoral approach and selective muscle stimulation.

RESULTS

Vocal fold opening movements could be evoked by the investigators in 9 of 12 PCA muscles to stimulate with similar electric parameters. The endoscopic approach using the ECE50 proved to be atraumatic and sufficiently controlled under sedation to locate the required hotspot for NMES of the PCA.

CONCLUSION

The functionality of the novel endoscopic cap concept has been proven in a porcine model. It can be expected to be transferable to human application and to be of diagnostic importance in the screening and identification of LP candidate patients in future.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:2279-2284, 2023.

Functional Evaluation of Larynx Nerve Stimulator With EMG Acquisition Capability and Wireless Connectivity

Recently, an electrical stimulation of the paralyzed muscle, as a potential therapy for restoring function of a denervated muscle system, has been debated as an innovative treatment in the management of patients with laryngeal paralysis. Numerous studies in acute and chronic animal models have demonstrated that electrical stimulation of the paralyzed posterior cricoarytenoideus muscle (PCA) offers an approach to induce vocal fold abduction and restore ventilation through the glottis. The study aims to test applicability of the controlled opening of the rima glottides via direct electrical stimulation of the posterior cricoarytenoideus muscle. We developed for this purpose a novel instrument system for the controlled larynx nerve stimulation. An acute experiment on the 4 years old pig showed effectiveness of the engineered stimulator. The controlled opening of rima glottidis of both posterior cricoarytenoid muscles and afterwards of both PCA muscle contraction were observed as a result of the electrical stimulation with the applied current in the range of 0.1-3 mA and pulse width of 1 ms and 10 ms. Performed research indicates a large potential of the novel nerve stimulator for the human larynx stimulation.