Artificial reflex arc: a potential solution for chronic aspiration. II. A canine study based on a laryngeal prosthesis.

Long-term and repeated aspiration can result in pneumonia and eventually death. To avoid current techniques which divert or close off the incompetent larynx, the authors have recently described an artificial reflex arc (ARA), in hopes of providing a dynamic solution to this problem. With this concept, a segment of skin surface with intact sensory innervation is implanted into the pharynx in the path of the food bolus. Resulting neural impulses would be detected by a perineural electrode and then channeled to both recurrent laryngeal nerves via an electronic pacemaker to cause vocal fold adduction at the critical time during swallowing. A pilot study using a tubed cervical cutaneous surface has yielded promising results in the canine. In this current study, an alternate means for information pickup based upon use of a miniature strain gage is presented. Mechanical stimulation of the hypopharynx using this "sensory" detector resulted in synchronous laryngeal adduction of the vocal folds, as documented graphically and on videotape.