Increasing airflow ventilation in a nasal maxillary ostium using optimised shape and pulsating flows.

Abstract

Ventilation of the maxillary sinus is essential for regulating pressure, preventing infection and providing mucous to the nasal anatomy. During infection, the pathway between the sinus and the nasal airway (ostia) can become inflamed and restrict ventilation. Surgery is often required to restore airflow. The current surgical standard involves the widening of the ostium. Although this restores fluid flow, it has been linked to post-surgical sequelae. This study examined the effects of pulsating flow and geometric modifications on airflow distribution in a T-junction model analogous to a nasal maxillary ostium. A circular T-junction with variable anterior and posterior radius of curvature ( $R_c$ ) was used to simulate airflow through the nasal maxillary ostium, investigating flow behaviour under oscillatory inlet velocities at frequencies of 30, 45, 60, and 75 Hz. Computational fluid dynamics (CFD) simulations assessed how flow distribution through the nasal cavity and maxillary ostium (represented by the x- and y-branches) is affected by curvature and oscillatory frequency, focusing on implications for respiratory airflow, particle delivery and inhalation toxicology. Results indicated that increasing the anterior $R_c$ enhanced airflow into the y-branch (analogous to the maxillary ostium), while posterior curvature had minimal impact. Higher oscillatory frequencies increased reverse flow, which may improve ventilation but could interfere with consistent drug delivery. These insights are valuable for optimising respiratory therapies and inhalation toxicology.