Numerical Study of Nebulizer Vibration Frequency Effects on Drug Droplet Deposition in the Maxillary Sinus Using Multiphase CFD Analysis
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The vibrating nebulizers are used for drug delivery to the maxillary sinus in the treatment of sinusitis.[1] Although computational fluid dynamics (CFD) analysis of airflow in the sinonasal cavity have been conducted, multiphase CFD analysis considering the effects of vibration-induced inflow conditions on drug droplet deposition remain limited. This study aimed to investigate the effects of nebulizer vibration frequency on drug droplet deposition in the maxillary sinus using multiphase CFD analysis. Three cases were analyzed: (1) normal sinonasal morphology (Case1), (2) nasal septal deviation accompanied by left nasal mucosa (Case2), and (3) nasal septal deviation (Case3). Patient-specific sinonasal geometries were reconstructed from medical imaging data, tetrahedral meshes were generated, and CFD analyses were conducted. A time-dependent inflow boundary condition representing a vibrating nebulizer was applied to either the left or right nostril, while the contralateral nostril was assumed to be closed. Drug droplets were modeled using Lagrangian particle tracking within the airflow field. Transient simulations over a finite time period (1.5 s) were conducted at inflow vibration frequencies of 0, 50, and 100 Hz, and the proportions of droplet deposition in the bilateral maxillary sinuses at the final time were compared. For the right maxillary sinus, the maximum droplet deposition was 0.0180% under right-side inflow at 100 Hz in Case1, 0.0373% under right-side inflow at 100 Hz in Case2, and 0.0179% under left-side inflow at 100 Hz in Case3. For the left maxillary sinus, droplet deposition was observed only in Case3; with a maximum value of 0.0175% under left-side inflow at 0 Hz. These results indicate that the inflow vibration frequency and inlet side that maximize droplet deposition into the maxillary sinus vary depending on patient-specific sinonasal geometry. Multiphase CFD analysis incorporating time-dependent inflow conditions may contribute to the evaluation and optimization of nebulizer treatment in patient-specific sinonasal models.
