Total ear canal ablation and lateral bulla osteotomy for treatment of otitis externa and media in a rabbit

Abstract

A 7-year-old spayed female Miniature Rex European rabbit (Oryctolagus cuniculus) was evaluated because of scratching at the right ear. Physical examination revealed purulent exudate in the right ear canal. Microbial culture of the exudate yielded Pseudomonas aeruginosa susceptible to marbofloxacin; however, the infection was refractory to appropriate medical treatment. Computed tomography revealed isoattenuating material within the right tympanic bulla and external ear canal with no enhancement following IV administration of contrast medium. The left tympanic bulla appeared normal. A total ear canal ablation and lateral bulla osteotomy were performed on the right ear, and polymethylmethacrylate beads containing either gentamicin or cefazolin were placed within the bulla and surrounding tissues. Two weeks after surgery, the patient appeared comfortable with no signs of scratching at the right ear. Total ear canal ablation and lateral bulla osteotomy can be successfully performed for treatment of chronic otitis externa and media in rabbits. Cartilage plates that compose the external ear canal, a bony acoustic duct, lack of a horizontal ear canal, and thickness of the lateral aspect of the tympanic bulla are features unique to rabbits and have not been described in relation to these surgical procedures in rabbits. Rabbits also produce a caseous exudate, and it is difficult to resolve infections of bone and soft tissues. Placement of antimicrobial-impregnated polymethylmethacrylate beads is recommended to minimize the risk of recurrent infection.