Maxillomandibular advancement is one of the treatments available for obstructive sleep apnea. The influence of this surgery on the upper airway and its mechanism are not fully understood. The present research simulates the flow fields of narrowed upper airways of 2 patients with obstructive sleep apnea treated with maxillomandibular advancement. The geometry of the upper airway was reconstructed from computed tomographic images taken before and after surgery. The consequent three-dimensional surface model was rendered for measurement and computational fluid dynamics simulation. Patients showed clinical improvement 6 months after surgery. The cross-sectional area of the narrowest part of the upper airway was increased in all dimensions. The simulated results showed a less constricted upper airway, with less velocity change and a decreased pressure gradient across the whole conduit during passage of air. Less breathing effort is therefore expected to achieve equivalent ventilation with the postoperative airway. This study demonstrates the possibility of computational fluid dynamics in providing information for understanding the pathogenesis of OSA and the effects of its treatment.
From the *Department of Plastic and Reconstructive Surgery, Craniofacial Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan; †Computational Application Division, National Center for High-Performance Computing, Hsinchu City; ‡Sleep Center, Departments of Chest Medicine and §Radiology, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan, Taiwan.
Received September 8, 2008.
Accepted for publication October 19, 2008.
Address correspondence and reprint requests to Yu-Ray Chen, MD, Craniofacial Center, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Chang Gung University, No.5 Fu-Hsin St, Guei-shan, Taoyuan, Taiwan; E-mail: email@example.com
This report is part of the project, NSC96-2314-B-182-018, supported by a grant from the National Science Council of Taiwan.