title: Aerodynamic characteristics inside the rhino-sinonasal cavity after functional endoscopic sinus surgery.
abstract: BACKGROUND
  The aim of this study was to evaluate effects of functional endoscopic sinus surgery (FESS) on transient nasal aerodynamic flow patterns using computational fluid dynamics (CFD) simulations.
  
  
  METHODS
  A three-dimensional model of the nasal cavity  was constructed from CT scans of a patient with FESS interventions on the right side of the nasal cavity. CFD simulations were then performed for unsteady aerodynamic flow modeling inside the nasal cavity as well as the sinuses.
  
  
  RESULTS
  Comparisons of the local velocity  magnitude and streamline distributions inside the left and right nasal cavity and maxillary sinus regions were presented. Because of the FESS procedures in the right nasal cavity, existences and distributions of local circulations (vortexes) were found to be significantly different for the  same nasal airflow rate but at different acceleration, deceleration, or quiet phases in the maxillary sinus region on the FESS side. Because of inertia effects, local internal airflow with circulation existences was continuous throughout the whole respiration cycle. With a larger peak inspiration  flow rate, the airflow intensity inside the enlarged maxillary sinus increased significantly. Possible outcomes on functional performances of the nose were also examined and discussed.
  
  
  CONCLUSIONS
  Surgical enlargements of natural ostium of the maxillary sinus will change  the aerodynamic patterns inside the main nasal cavity and maxillary sinus regions, which may affect normal nasal physiological functions. Local inertia effects play more important roles for the internal nasal airflow pattern changes and thus such conventional FESS procedures should be carefully  planned.
authors.affiliation: Department of Mechanical Engineering, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Xiao Bing
authors.initials: XB
authors.lastname: Chen
authors.forename: Heow Pueh
authors.initials: HP
authors.lastname: Lee
authors.forename: Vincent Fook Hin
authors.initials: VF
authors.lastname: Chong
authors.forename: De Yun
authors.initials: de Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D002908:Chronic Disease; D019295:Computational Biology; D003198:Computer Simulation; D004724:Endoscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D009296:Nasal Cavity / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D010256:Paranasal Sinuses / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D012119:Respiration; D012220:Rhinitis; D012852:Sinusitis; D014057:Tomography, X-Ray Computed