Abstract
Cochlear changes produced by chronic perilymphatic fistula were studied by inserting a 0.47mm dia. plastic cannula into the scala tympani of the basal turn of the cochlea of guinea pigs. About a month later, changes in cochlear blood flow and hair cell morphology were studied using the microsphere surface preparation technique. When the tube was patent and confined to the scala tympani, no cochlear histopathology was evident. In some animals, hair cell damage and reduction in cochlear blood flow was present, perhaps due to direct tubal injury to the cochlear duct or to an unknown factor induced by the chronic fistula. Therefore, a chronic perilymphatic fistula limited to scala tympani causes no cochlear damage.
