Evolution of middle ear changes after permanent eustachian tube blockage

Objective: To develop a valid animal model for otitis media with effusion (OME). Design: Forty specific pathogen-free Wistar rats underwent a procedure based on the permanent obstruction of pharyngeal eustachian tube by means of electrocoagulation without any manipulation. Setting: Ear Research Group, Department of Otorhinolaryngology, Puerta de Hierro Hospital, Universidad Antonoma de Madrid, Madrid, Spain. Main Outcome Measures: The assessment of OME by otoscopy and tympanometry. The rats were humanely killed at 15 and 90 days, and temporal bones were obtained and processed for histopathologic study. Results: The histopathologic study of the temporal bones demonstrated the occurrence of chronic effusion and mucosal changes owing to mucoperiosteal enlargement. Conclusions: Comparison with other experimental models was made. Our animal model was consistent and reproducible and resembled human OME.