Three-dimensional Morphological Evaluation And Computational Fluid Dynamics Simulation Of The Upper Airway Response To Nasal Obstruction In Growing Rat

Objectives:This study is based on three-dimensional(3D)reconstruction of Micro-CT data and computational fluid dunamics(CFD)simulation to evaluate the morphological and CFD response of the upper airway to nasal obstruction in growing rat,to study the influence of nasal obsturction on the growth and development of the upper airway.Materials and Methods:Twenty three-week-old male Wistar rats were divided into two groups:Group A:the control group(n= 10),Group B:both nostrils occluded by nose plugs(n=10).The occlusion period was between 8 a.m.and 4 p.m.lasting 8 hours every day.Seven weeks later all rats were anesthetized and remained supine position to gather the Micro-CT scan data.3D reconstruction and registration of each data were performed by MIMICS 17.0 and pharyngeal flow field characteristic were simulated with ANSYS16.0.The variations of upper airway between Group A and B were analyzed with t-tests by SPSS19.0.Statistical significance was set at P<0.05.The relationship between pharyngeal airflow resistance and morphological variables was analyzed by Pearson correlation cofficient.Results:The volume(V)and mean cross-sectional area of the upper airway decrease in Group B,especially in oropharynx.In this position,the morphological unifornity(Smin/Smean)is Group A supeerior to Group B.After numerical simulation of airflow,the minimun pressure occurs in hypopharynx.However,the maximun pressure drop and velocity exsisted in oropharynx.In this position,there was a obvious negative correlation between the pressure drop and morphological variables(V,Smean,Smin/Smean).Conclusions:The morphology and respiratory function decrease due to nasal obstruction during development period.