Expansion hyoidplasty: a potential surgical procedure designed for selected patients with obstructive sleep apnea syndrome. Experimental canine results.

Some patients with "idiopathic" obstructive sleep apnea syndrome have an inspiratory, circumferential, passive collapse of the hypopharyngeal lumen as the mechanism of airway obstruction. Permanent tracheotomy has offered documented dramatic resolution of the airway obstruction with reversal of the associated cardiopulmonary sequelae. Tracheotomy is not, however, without psychological and physical complications detracting from its use. In hope of developing a surgical alternative, the expansion hyoidplasty was conceived. The hyoid bone is transected just medial to each lesser cornu. The trisected hyoid bone is then held in an expanded position by a permanent stainless steel brace. The greater cornua with attached middle constrictor and hyoglossus are moved laterally, while the body of the hyoid with attached geniohyoid and genioglossus shift the base of tongue anteriorly. The procedure is potentially reversible. Twenty dogs were studied pre and posthyoid expansion. Superior hypopharyngeal pressure-volume and closing pressures were obtained on 10 dogs. The pressure-volume studies demonstrate a consistent expansion of the superior hypopharynx. The average drop in pressure varied from 2.9 to 12.4 cm H2O in different animals. All posthyoid expansion dogs showed an average increase in closing pressure ranging from -4.4 to -28.3 cm H2O. Deglutition and laryngeal competence were not grossly effected. These results support the continued experimentation towards implementation of the expansion hyoidplasty in humans.