Comparison of Long Term Outcome in Cats with and Without Clinical Inner Ear Disease Undergoing Ventral Bulla Osteotomy

Introduction:
The purpose of the study was to evaluate the presence of pre-operative otitis interna as a prognostic indicator for outcome and recurrence in cats undergoing ventral bulla osteotomy (VBO).

Methods:
Medical records of cats undergoing VBO surgery were reviewed. Cats were assigned to two groups, presentation with (group A) or without (group B) clinical signs of otitis interna. Follow-up was obtained by telephone from both referring veterinarians and owners after a minimum follow- up of three months.

Results:
Thirty-four cats were included in the study. Twenty-one cats presented with at least one of the following: head tilt (n=10), nystagmus (4) or vestibular ataxia (11) before surgery (group A), and thirteen without signs of otitis interna (group B). Advanced diagnostic imaging confirmed unilateral or bilateral diseases in all but 4 patients, which presented with unilateral clinical signs but were diagnosed with bilateral middle ear disease. Eight cats underwent bilateral VBO. Surgery was uneventful in all patients but some patients exhibited newly acquired vestibular signs after surgery and Horner’s syndrome in the immediate postoperative period. All patients except one survived to hospital discharge. Histopathologic evaluation revealed an inflammatory polyp in 21 cats. Sixteen cats from group A (76%) and twelve from group B (92%) recovered from their clinical signs (p<0.05), with only one cat (group B) relapsing.

Conclusion:
Cats with inner ear disease on presentation did not have increased morbidity or mortality associated with VBO, nor an increased risk for recurrence but they were less likely to make a full recovery.