Three‐Dimensional Changes in the Upper Airway During Neuromuscular Stimulation of Laryngeal Muscles

Abstract

During swallowing, airway protection depends upon adequate glottal closure and laryngeal elevation to prevent the entry of substances into the airway. Three-dimensional changes in the upper airway during laryngeal muscle stimulation in a canine model were quantified in animals implanted with Peterson type stimulating electrodes in the inferior and superior portions of the thyroarytenoid muscle, together with a reference electrode. Computer tomography scanning was performed on an IMATRON scanner with a 3 mm slice thickness advanced at overlapping 1 mm increments. Stimulation of the thyroarytenoid muscle produced adductions of the vocal fold towards the midline and changes in the supraglottic region as well as the glottis; the glottic wall was compressed medially above and below the glottis. These results suggest that chronic neuromuscular stimulation can effect glottic protection by reducing the glottal opening and may be beneficial for patients with central control disorders affecting airway protection during swallowing.

Correspondence between laryngeal vocal fold movement and muscle activity during speech and nonspeech gestures

“…Spiral computerized tomography imaging of the vocal tract could provide increased information on changes in vocal tract shaping and the superior-inferior extent of movement associated with adductor muscle activity. The use of computerized tomography, however, would require extensive event-related sampling to visualize changes in shape associated with rapid changes in laryngeal muscle activity (45), causing significant radiation exposure in subjects.…”

Dynamic Laryngotracheal Closure for Aspiration: A Preliminary Report

“…Moreover, the role which vocal fold closure plays in concluding the swallowing cascade does not preclude rehabilitation of other allied, but possibly less pivotal, functions involved in safe swallowing. Laryngeal elevation 13 and cricopharyngeal relaxation combined with glottic closure, 9,10 already shown to be feasible in laboratory animals, could also be combined with the current approach. Also, patients who have benefited from muscle exercise during speech therapy may further improve as electrical stimulation increases strength in the striated musculature.…”

“…Preliminary studies done in canine models have demonstrated that neuroprosthetic devices could be used to this effect with 9,10 or without 11,12 coordinated cricopharyngeal relaxation, or laryngeal elevation. 13 Successful restoration of function in clinically unrelated fields (functional electrical stimulation [FES]), such as urology 14 and diaphragmatic pacing, 15 using ongoing progress in circuit miniaturization have encouraged applications in otolaryngology–head and neck surgery.…”

Chronic intermittent stimulation of the thyroarytenoid muscle maintains dynamic control of glottal adduction

“…The same animals were used in a pilot study aimed at determining the 3-dimensional changes in the upper airway during thyroarytenoid muscle stimulation. 26 CT scanning was conducted on an Imatron CT scanner (C-100XL Scanner, Imatron Corp., San Francisco, CA) under ketamine anesthesia. The images made at the level of the larynx without stimulation were included in this investigation to examine electrode position in the inferior thyroarytenoid muscle relative to the degree of vocal fold closure achieved during bilateral stimulation.…”