An investigation of upper airway changes associated with mandibular advancement device using sleep videofluoroscopy in patients with obstructive sleep apnea.

OBJECTIVE To quantitatively evaluate the effects of the mandibular advancement device (MAD) on changes in the upper respiratory tract during sleep using sleep videofluoroscopy (SVF) in patients with obstructive sleep apnea (OSA). DESIGN Retrospective analysis. SETTING Academic tertiary referral center. PATIENTS Seventy-six patients (68 men and 8 women) who were treated with the MAD for OSA were included from September 1, 2005, through August 31, 2008. INTERVENTION All patients underwent nocturnal polysomnography and SVF before and at least 3 months after receipt of the custom-made MAD. Sleep videofluoroscopy was performed before and after sleep induction and was analyzed during 3 states of awakeness, normoxygenation sleep, and desaturation sleep. MAIN OUTCOME MEASURES Changes in the length of the soft palate, retropalatal space, retrolingual space, and angle of mouth opening were evaluated during sleep events with or without the MAD. RESULTS Without the MAD, the length of the soft palate and the angle of mouth opening increased during sleep events, especially in desaturation sleep, compared with the awake state. The retropalatal space and retrolingual space became much narrower during sleep compared with the awake state. The MAD had marked effects on the length of the soft palate, retropalatal space, retrolingual space, and angle of mouth opening. The retropalatal space and retrolingual space were widened, and the length of the soft palate was decreased. The MAD kept the mouth closed. CONCLUSIONS Sleep videofluoroscopy showed dynamic upper airway changes in patients with OSA, and the MAD exerted multiple effects on the size and configuration of the airway. Sleep videofluoroscopy demonstrated the mechanism of action of the MAD in patients with OSA. The MAD increased the retropalatal and retrolingual spaces and decreased the length of the soft palate and the angle of mouth opening, resulting in improvement of OSA.