[Effect of endoscopic sinus surgery on airflow of the nasal cavity and paranasal sinuses: a computational fluid dynamics study.].

OBJECTIVE: To study the airflow velocity, trace, distribution, pressure, as well as the airflow exchange between the nasal cavity and paranasal sinuses in a computer simulation of nasal cavity pre and post virtual endoscopic sinus surgery (ESS). METHODS: Computational fluid dynamics (CFD) technique was applied to construct an anatomically and proportionally accurate three-dimensional nasal model based on a healthy adult woman's nasal CT scans. A virtual ESS intervention was performed numerically on the normal nasal model using Fluent 6.1.22 software. Navier-Stokes and continuity equations were used to calculate and compare the airflow characteristics between pre and post ESS models. RESULTS: (1) After ESS flux in the common meatus decreased significantly. Flux in the middle meatus and the connected area of opened ethmoid sinus increased by 10% during stable inhalation and by 9% during exhalation. (2) Airflow velocity in the nasal sinus complex increased significantly after ESS. (3) After ESS airflow trace was significantly changed in the middle meatus. Wide-ranging vortices formed at the maxillary sinus, the connected area of ethmoid sinus and the sphenoid sinus. (4) Total nasal cavity resistance was decreased after ESS. (5) After ESS airflow exchange increased in the nasal sinuses, most markedly in the maxillary sinus. CONCLUSIONS: After ESS airflow velocity, flux and trace were altered. Airflow exchange increased in each nasal sinus, especially in the maxillary sinus.