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 Autonoma 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.