Keywords: sheep, otologic surgery, experimental model, morphology

Abstract: Introduction: The animals which are currently employed as models for research and training in otosurgery, such as dogs, cats, and monkeys, have a different body size than humans; in addition, they are difficult to handle in a laboratory environment, because they are aggressive and susceptible to disease. The present study was conducted to evaluate the applicability of sheep as an experimental model for otological procedures. This animal was chosen due to its rusticity, availability and low cost. Material and methods: Preliminary anatomical and histologic studies were carried out through the dissection of six temporal bones, and through histopathological analysis of these temporal bones. Next, 12 sheep were submitted to an experimental surgical procedure (involving anesthesia) in the inner ear and vestibule. The response of the animals to pre-, trans- and postoperative procedures, confinement, and anesthesia was recorded. Results: The preliminary morphological study revealed significant similarities between human beings and sheep in terms of ear anatomy, especially concerning the size of the structures. Regarding the surgical intervention, our results show that sheep are very resistant. No major events were registered during the pre- trans- and late postoperative periods. Fourteen complications were registered during the early postoperative period. There was one case of infection, controlled with antibiotic therapy; seven animals presented static imbalance, and among these, five also presented dynamic imbalance which disappeared in all cases after 24 hours. There was one case of death by aspiration. Conclusions: Sheep may be useful as a model for experimentation and training in otologic surgery.