title: Numerical simulation of pharyngeal airflow applied to obstructive sleep apnea: effect of the nasal cavity in anatomically accurate airway models.
abstract: Repetitive brief episodes of soft-tissue collapse within the upper airway during sleep characterize obstructive sleep apnea (OSA), an extremely common and disabling disorder. Failure to maintain the patency of the upper airway is caused by the combination of sleep-related loss of compensatory dilator muscle activity and aerodynamic forces promoting closure. The prediction of soft-tissue movement in patient-specific airway 3D mechanical models is emerging as a useful contribution to clinical understanding and decision making. Such modeling requires reliable estimations of the pharyngeal wall pressure forces. While nasal obstruction has been recognized as a risk factor for OSA, the need to include the nasal cavity in upper-airway models for OSA studies requires consideration, as it is most often omitted because of its complex shape. A quantitative analysis of the flow conditions generated by the nasal cavity and the sinuses during inspiration upstream of the pharynx is presented. Results show that adequate velocity boundary conditions and simple artificial extensions of the flow domain can reproduce the essential effects of the nasal cavity on the pharyngeal flow field. Therefore, the overall complexity and computational cost of accurate flow predictions can be reduced.
authors.affiliation: Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia. julien.cisonni@gmx.com.
authors.forename: Julien
authors.initials: J
authors.lastname: Cisonni
authors.affiliation: Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia.
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Lucey
authors.affiliation: Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia.
authors.forename: Andrew J C
authors.initials: AJ
authors.lastname: King
authors.affiliation: Fluid Dynamics Research Group, Department of Mechanical Engineering, Curtin University, Perth, WA, Australia.|School of Dentistry/Oral Health Centre of Western Australia, University of Western Australia, Crawley, WA, Australia.
authors.forename: Syed Mohammed Shamsul
authors.initials: SM
authors.lastname: Islam
authors.affiliation: Perth Head and Neck Surgery, Nedlands, WA, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Lewis
authors.affiliation: School of Dentistry/Oral Health Centre of Western Australia, University of Western Australia, Crawley, WA, Australia.
authors.forename: Mithran S
authors.initials: MS
authors.lastname: Goonewardene
mesh_terms: D000328:Adult; D003198:Computer Simulation; D006801:Humans; D057446:Hydrodynamics; D008297:Male; D008954:Models, Biological; D009296:Nasal Cavity / Q000502:physiology*; D010614:Pharynx / Q000502:physiology*; D011312:Pressure; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*
keywords: Computational fluid dynamics (CFD); Nasal cavity; Obstructive sleep apnea; Pharyngeal wall pressure