Three-dimensional upper-airway changes with maxillomandibular advancement for obstructive sleep apnea treatment

Introduction: Airway size increases are associated with maxillomandibular advancement (MMA) surgery and improvement or elimination of obstructive sleep apnea (OSA). The 3-dimensional morphologic, volumetric, height, cross-sectional surface area, and diameter changes of the upper airway in patients with OSA after MMA, however, are not well understood. Methods: Patients with moderate or severe OSA who underwent MMA surgery were evaluated by preoperative and postoperative cone-beam computed tomography scans and polysomnograms. The upper airway space was also divided into retropalatal and retroglossal spaces and was analyzed for volumetric, height, cross-sectional surface area, transverse, and anteroposterior diameter changes. Results: Ten consecutive OSA patients with an average preoperative apnea/hypopnea index of 46 and treated with MMA surgery were included in this study. There were 8 men and 2 women, with an average age of 46 years and an average body mass index of 28. There was an average of a 2.5-fold increase in the total volume of the upper airway space. The retropalatal space increased by 3.5-fold. The retroglossal space increased by 1.5-fold. The greatest change in a cross-sectional area occurred in the transverse axis in both the retroglossal and retropalatal spaces. The average apnea/hypopnea index was 4 postoperatively. Conclusion: MMA surgery results in a significant increase in the volume and a morphologic airway change from a round to an elliptical f shape in the upper airway space in patients with OSA. The combination of these actions reduces the collapsibility of the upper airway space, hence improving or resolving the OSA.