Protecting the cochlea during stapes surgery: is there a role for corticosteroids?

The aim of the present study was to evaluate possible protective effects of corticosteroids on the inner ear after surgical trauma and to exclude any ototoxicity. A corticosteroid (triamcinolone, Volon A) was topically applied to the inner ear of guinea pigs, either by extracochlear application with permeation and diffusion through the round window membrane or by intracochlear application with direct infusion into the inner ear via a cochleostomy. Threshold and input/output functions of compound action potentials (CAPs) were determined before and after application of the corticosteroid. We found that extracochlear application of the corticosteroid induced insignificant mild shifts of mean CAP thresholds, but significantly increased mean maximal amplitudes of input/output function after the 14th day following application of the steroid. No detrimental effects on cochlear function were noted in the extracochlear group, indicating absence of ototoxicity with the concentrations used. In the intracochlear group, CAP thresholds and amplitudes of input/ output function recovered from partial hearing loss due to cochleostomy between 7 and 14 days after application of the steroid, whereas in controls without steroid application, no such recovery of hearing was detected. These results suggest that topical application of triamcinolone has no ototoxic effect and that it leads to increased recovery of cochlear functions after trauma in the guinea pig inner ear.