Direct round window application of gentamicin with varying delivery vehicles: a comparison of ototoxicity.

Objective: To evaluate patterns of ototoxic damage sustained from gentamicin applied directly to the round window in varying delivery vehicles.

Setting: The search for a reliable method of drug delivery to the inner ear continues. Vehicles such as Gelfoam, hyaluronic acid, and fibrin may allow for a more reproducible pattern of ototoxic damage.

Study Design: Histological evaluation of vestibular and cochlear damage was performed on Mongolian gerbils after a known dosage of gentamicin in different delivery vehicles.

Results: Variable ototoxic damage was caused by Gelfoam and fibrin-based vehicles. No ototoxic damage was found in the Healon vehicle. The vehicle of fibrin and Gelfoam combined resulted in severe damage. There was no evidence of selective cochlear or vestibular ototoxicity in any of the vehicles tested.

Conclusions And Significance: The fibrin/Gelfoam vehicle was the only delivery system to produce reliable damage. Ototoxic damage depended on the vehicle. We found no evidence for selective vestibular ototoxicity with gentamicin.