Ocular examinations before and after total ear canal ablation and bulla osteotomy can help recognize and prevent potential vision-threatening abnormalities in cats and dogs

Objective: To report ocular examination findings before and after total ear canal ablation and lateral bulla osteotomy (TECALBO) and ventral bulla osteotomy (VBO) in cats and dogs.

Methods: At The Ohio State University and MedVet Columbus, ophthalmic examinations were performed on client-owned animals for which a TECALBO or VBO was indicated. Examination findings and postoperative complications relating to ophthalmic and/or neuro-ophthalmic diseases were recorded prior to surgery (T0) and at 1 day (T1), 2 to 3 weeks (T14), and ± 2 months (T60) postoperatively.

Results: 28 dogs and 22 cats underwent 43 TECALBO and 20 VBO surgeries (63 ears). Reasons for surgery included otitis (52.4%), polyps (30.1%), and aural masses (17.5%). Facial nerve deficits were observed preoperatively in 5.7% of surgeries and postoperatively in 47.2% at T1 and 31.3% at T14. Horner syndrome was present preoperatively in 11.3% and postoperatively in 45.3% at T1 and 37.5% at T14. Keratoconjunctivitis sicca and corneal ulcers were noted, respectively, in 5.7% and 3.8% of cases at T0 and 5.7% and 17% at T1. Facial nerve deficits and Horner syndrome remained present in 29% (5 of 17) and 36% (5 of 14) at T60. One dog with preoperative facial nerve paralysis and Horner syndrome developed a descemetocele that required a conjunctival flap at T14. Overall, 64.2% of surgeries led to ocular and/or neuro-ophthalmic changes postoperatively.

Conclusions: Cats and dogs undergoing TECALBO and VBO procedures should have thorough ophthalmic examinations preoperatively and postoperatively, as ocular and neuro-ophthalmic abnormalities are common in these patients.

Clinical relevance: Ocular examinations are important in animals undergoing aural surgeries in order to reveal ocular abnormalities that could require follow-up care or lead to vision-threatening conditions.