An Animal Model for the Study of Topical Medications in Sinusitis

Abstract

Rhinosinusitis after functional endoscopic sinus surgery often is recalcitrant to conventional medical management. Topical therapies have been popularized as a method to deliver powerful medications to diseased mucosa while limiting systemic toxicity. The aim of this study was to develop an animal model that will provide objective data in studying the efficacy of topical medications and establish a platform for translation to human clinical trials. The maxillary sinus ostium of white rabbits was obstructed with a pledget through an antrostomy created in the anterior face of the maxilla. The sinus was inoculated with Pseudomonas aeruginosa (PAO1) and 7 days later the antrostomy was reopened, the ostial obstruction was removed, and a single lumen catheter was placed. Normal saline was irrigated through the catheter for 7 days in one group of rabbits while a control group received no irrigation. At the end of 7 days, the rabbits were euthanized, analyzed under light microscopy, and bacterial counts of the nasal lavage were determined. Sinusitis was confirmed in all rabbits 7 days after inoculation. Purulence, mucosal, and underlying bony inflammation persisted in both the control and the saline irrigation groups at study end. Nasal lavage bacterial counts were persistently elevated throughout the study period, indicative of bacterial viability. An animal model has been created for the study of topical medications in sinusitis. A novel catheter delivery system within an unoccluded maxillary sinus is described that will aid in efficacy studies of topical medications in the management of recalcitrant rhinosinusitis.