Artificial reflex arc: a potential solution for chronic aspiration. I. Neck skin stimulation triggering strap muscle contraction in the canine.
Aspiration can occur when the reflex of deglutition occurring in the brain stem is impaired. Surgical procedures involving the airway have so far failed to provide a long-term solution to this problem. Because the sphincteric properties of the larynx could be used to help separate the air from the food passages on a dynamic basis, we present the concept of an artificial reflex are (ARA) in the canine. The afferent limb of this system consists in a cervical cutaneous sensory surface containing the specific biologic sensors for pressure and stretch, subtended by a corresponding sensory nerve, destined to be eventually implanted into the pharynx. The efferent limb picks up the information resulting from the sensor's distention via a frequency modulator and an amplifier, prior to transmitting it to the recurrent laryngeal nerves through monopolar electrodes, resulting in synchronous glottic closure. In order to test this new concept as a pilot study, this principle was applied in three dogs by using an island of cervical skin tubed on itself and the contralateral strap muscles as effector. Inflation of a Foley catheter introduced into the lumen of this tube resulted in synchronous strap muscle contraction, following corresponding increase in the firing frequency in the subtended sensory nerve. The data obtained in this series of experiments should permit further application at the laryngeal level.