Purpose: To evaluate changes in airway size and shape in patients with obstructive sleep apnea (OSA) after maxillomandibular advancement (MMA) and genial tubercle advancement (GTA). Materials and Methods: This was a retrospective cohort study, enrolling a sample of adults with polysomnography-confirmed OSA who underwent MMA + GTA. All subjects who had preoperative and postoperative 3-dimensional computed tomography (CT) scans to evaluate changes in airway size and shape after MMA + GTA were included. Preoperative and postoperative sleep- and breathing-related symptoms were recorded. Descriptive and bivariate statistics were computed. For all analyses, P < .05 was considered statistically significant. Results: During the study period, 13 patients underwent MMA + GTA, of whom 11(84.6%) met the inclusion criteria. There were 9 men and 2 women with a mean age of 39 years. The mean body mass index was 26.3; mean respiratory disturbance index (RIM), 48.8; and mean lowest oxygen saturation, 80.5%. After MMA + GTA, there were significant increases in lateral and anteroposterior airway diameters (P < .01), volume (P = .02), surface area (P < .01), and cross-sectional areas at multiple sites (P < .04). Airway length decreased (P < .01) and airway shape (P = .04) became more uniform. The mean change in RDI was -60%. Conclusions: Results of this preliminary study indicate that MMA + GTA appears to produce significant changes in airway size and shape that correlate with a decrease in RDI. (C) 2011 American Association of Oral and Maxillofacial Surgeons Oral Maxillofac Surg 69:677-686, 2011