Correlation between nasal airflow characteristics and clinical relevance of nasal septal deviation to nasal airway obstruction.

Since the imbalance of the nasal cavities due to nasal septal deviation (NSD) is a commonly observed anatomic variation in healthy adults, clinicians must often decide whether or not it is clinically relevant to the symptoms of nasal airway obstruction (NAO). Main reason for this is a lack of data correlating the symptoms of NAO with objective findings. The aim of our study is to find the correlation between fluid dynamic parameters and the anatomy of nasal cavity with NSD by numerical simulation. We generated 6 computational models of nasal cavities with NSD were created from computed tomographic images: 3 symptomatic patients with NAO and 3 asymptomatic patients. Computational fluid dynamics (CFD) was used to simulate steady inspiratory airflows in each nasal cavity model and compare the fluid dynamic properties of each. In the symptomatic cases, the pressure drop from the naris to the end of the septum was larger, and more uneven flow partitioning was observed. Local maximum velocity and wall shear stress were higher in the symptomatic group than in the asymptomatic group. The symptoms of NAO seem to be related more to the nasal resistance from the naris to the end of the septum than to the total nasal resistance from naris to nasopharynx. Factors correlated with NAO by CFD can be used as elements in patient-specific objective diagnostic tools for NAO in the presence of NSD.