Differential deposition of aerosols in the maxillary sinus of human cadavers by particle size

Background: Topical delivery of nebulized antibiotics to the paranasal sinuses has been shown to improve clinical outcomes in patients with chronic sinus disease after functional endoscopic sinus surgery (FESS). The most efficient method for delivering nebulized particles to the sinuses, however, has not been established. This study investigates how the size of nebulized particles influences the efficiency of deposition in the maxillary sinus of human cadavers after FESS. Methods: Endoscopic maxillary antrostomy was performed on eight sides in four cadavers. Each cadaver's nasal vault was nebulized with technetium99m-labeled sulfur colloid particles of three size ranges. Anterior-posterior and left lateral static gamma-camera images of the head were captured with an acquisition cutoff limit of 30,000 gamma-count. Regions of interest were defined for the left and right maxillary sinus and gamma-photon counts were recorded. Analysis of variance (ANOVA) for repeated measures and paired t-test were used to determine statistical significance. Results: Mean diameter of particles generated was 6, 0.99, and 0.67 μm. There was a statistically significant difference in deposition between the largest particle size and the two smaller sizes, with a mean gamma-photon count of 254 for 6-μm particles versus 811 for 0.99-μm particles and 835 for 0.67-μm particles (ANOVA, p = 0.002). Conclusion: Particles in the 0.67- to 0.99-μm range had improved efficiency of deposition in the maxillary sinus compared with larger particles after maxillary antrostomy. Larger particles appeared to deposit directly in the nasal vault while smaller particles were more likely to reach the maxillary sinus.