Partial preservation of the inferior turbinate in endoscopic medial maxillectomy : a computational fluid dynamics study

Background: Endoscopic medial maxillectomy (EMM) is a workhorse for multiple sinonasal conditions. To reduce its burden on the sinonasal physiology, several modified EMM (M-EMM) have been proposed. Objective: In order to provide a theoretical basis for EMM and its modifications, this study introduces a computational fluid dynamics (CFD) model, based on a time-resolved direct numerical simulation, describing EMM and assessing the role of the M-EMM in preserving the overall fluid dynamics of the sinonasal cavities. Methods: A normal sinonasal CT scan was converted into a geometrical model and used as a reference; 2 anatomies were then created by virtual surgery, mimicking EMM and M-EMM, with the latter sparing the anterior portion of inferior turbinate and medial maxillary sinus wall. The airflow was simulated in the models via the OpenFOAM CFD software and compared in terms of flow rate, mean and fluctuating velocity, vorticity, and turbulent structures. Results: The analysis shows that EMM induces a massive flow rate increase in the operated side, which becomes less obvious in the M-EMM model. In contrast to M-EMM, EMM induces higher velocity fields that reach the maxillary sinus. Velocity and vorticity fluctuations are negligible in the baseline model, but become increasingly evident and widespread in the M-EMM and EMM models. Conclusions: A significant disruption of the nasal fluid dynamics is observed in EMM, while M-EMM minimizes variations and reduces interference with nasal air conditioning. Our analysis provides insights into the pathophysiology of radical sinus surgery and provides a theoretical basis for the ability of M-EMM to reduce the temporary surgery-related changes on both healthy and operated sides.