Cochlear pathology following experimental ablation of the vestibular labyrinth.

A surgical procedure was performed on 24 cats in which the oval window was entered and the vestibular sense organs were ablated. The operation incited a severe reparative response in the vestibule, characterized by proliferation of fibrous tissue and bone and blockage of the longitudinal flow of endolymph. One inner ear became infected resulting in degeneration of the labyrinth. Of the remaining 23 ears, 20 showed cochlear endolymphatic hydrops (EH) and three did not. All three ears without cochlear EH (as well as two ears with cochlear EH) had fistulae of their endolymphatic systems. The findings are consistent with the concept that fistulization of the membranous labyrinth prior to the blockage of longitudinal flow will prevent the formation of EH. Similarly, fistulization occurring after the onset of EH should arrest its progression. These observations are relevant for surgical procedures designed to control intractable vertigo caused by EH.