Postoperative hearing recovery in a case of delayed hearing loss after acoustic neurinoma removal.

Delayed postoperative hearing loss after acoustic neurinoma removal is seldom observed. The presented case illustrates the phenomenon of delayed postoperative hearing loss which was observed 4 days after removal of a large acoustic neurinoma. Intraoperative brainstem auditory evoked potentials (BAEP) revealed a gradual loss of wave V with preservation of wave I. In animal experiments a dissociated loss of BAEP has been associated with impairment of microcirculation due to secondary edema. Vasoactive treatment was initiated and after 11 days a partial hearing recovery could be documented. Transient disturbance in microcirculation of vasa nervorum of the cochlear nerve is assumed to be responsible for postoperative hearing fluctuation.