Numerical simulation of airflow patterns in nose models with differently localized septal perforations.

OBJECTIVES/HYPOTHESIS The most typical complaints of patients with nasal septal perforation (SP) are nasal obstruction, crusting, and recurrent epistaxis depending on the size and site of the SP mainly due to disturbed airflow patterns. The objective of the study was to determine the influence of differently localized SPs on intranasal airflow patterns during inspiration by means of numerical simulation. STUDY DESIGN An experimental setup using three dimensional computer models of a human nose was created. Four different models with three differently localized septal perforation allowed an examination of intranasal airflow changes. METHODS Four high-resolution, realistic, bilateral computer models of the human nose with three differently localized SPs were reconstructed based on computed tomography. A numerical simulation was performed. The intranasal airflow patterns (path lines, velocity, turbulent kinetic energy) during inspiration were displayed, analyzed, and compared. RESULTS SPs cause a highly disturbed airflow in the area of the SP and behind. A spacious vortex within the perforation, including various localized vortices, was detected. The airflow in the nose was disturbed to varying degrees depending on the location of the perforation. SPs within the anterior caudal septum in area II led to increased negative turbulences and crossflow. CONCLUSIONS The numerical simulations demonstrate significantly disturbed intranasal airflow patterns due to SPs. This fact may contribute to crusting and nosebleed due to dehydration of the nasal mucosa. The location and size of the SP are crucial for the impact on disturbed airflow pattern and therefore the patients' complaints. Anterior caudal SPs seem to be the worst. Surgical closure of SPs or simply changes in the site and size of the SP if a complete closure is surgically impossible makes sense.