Vasoactive treatment for hearing preservation in acoustic neuroma surgery

Object. Delayed hearing loss following surgery for acoustic neuroma indicat es anatomical and functional preservation of the cochlear nerve and implies that a pathophysiological mechanism is initiated during surgery and contin ues thereafter. Intraoperative brainstem auditory evoked potentials (BAEPs) typically demonstrate gradual reversible loss of components in these patie nts. Methods. Based on this BAEP pattern, a consecutive series of 41 patients wi th unilateral acoustic neuromas was recruited into a prospective randomized study to investigate hearing outcomes following the natural postoperative course and recuperation after vasoactive medication. Both groups were compa rable in patient age, tumor size, and preoperative hearing level. Twenty pa tients did not receive postoperative medical treatment. In 70% of these pat ients anacusis was documented and in 30% hearing was preserved. Twenty-one patients were treated with hydroxyethyl starch and nimodipine for an averag e of 9 days. In 66.6% of these patients hearing was preserved and in 33.3% anacusis occurred. Conclusions. These results are statistically significant (p < 0.05, chi (2) = 5.51) and provide evidence that these surgically treated patients suffer from a disturbed microcirculation that causes delayed hearing loss followi ng removal of acoustic neuromas.