0587 WHERE DOES PHASE1 SLEEP SURGERY INCLUDING GENIOGLOSSUS ADVANCEMENT ENLARGE THE AIRWAY?

Abstract

Introduction: CPAP and OA are typical conservative treatments for Obstructive Sleep Apnea (OSA), but decreased adherence can be a problem for using each device. Therefore, we suggest Sleep Surgery (SS) as an alternative treatment for OSA. SS is performed in two phases according to the Stanford protocol. Phase1 is performed on the soft tissues (nasal cavity, pharynx, tongue). The effects of Phase1 are evaluated by Polysomnography (PSG) and CT imaging, and if insufficient, Maxillomandibular advancement (Phase2) is suggested. Genioglossus Advancement (GA) enlarges the pharyngeal airway by traction of the genioglossus and geniohyoid muscles. We investigated where the pharyngeal airway is enlarged by Phase1 including GA. Methods: We enrolled 22 OSA patients who were diagnosed by PSG and consented to CT imaging at the Ota Memorial Sleep Center before and after Phase1 including GA. Cases where AHI decreased by more than 50% after surgery and became 20/h or less were included in the effect group, and the other cases were included in the non-effect group. The pharyngeal airway measurement sites were the second cervical vertebra (SCV) area (Superior, Median and Inferior) and the Base of the Epiglottis. The anteroposterior and lateral diameters were measured and compared. Results: There were 6 cases in the effect group and 16 cases in the non-effect group, and the overall success rate was 27%. The anteroposterior diameters of both groups were not changed, but the lateral diameter was expanded significantly in all of the SCV area of the effect group. Conclusion: This study confirmed that expansion of the pharyngeal airway was not in the anteroposterior diameter, but the lateral diameter was increased by Phase1 including GA. However, the overall success rate was low, and the number of cases needs to be increased in the future to decide on indications and to devise improved techniques for surgery.