Auditory Monitoring in Acoustic Neuroma Surgery

Auditory monitoring is essential in cases of acoustic neuroma surgery attempting hearing preservation. ABR monitoring is widely used but reliability is problematic due to the long procedure of wave registration, thus cessation of auditory brainstem response is detected too late. We report our experience using intraoperatively both ABR and transtympanic electrocochleography (EcochG) as auditory monitoring on 178 acoustic neuromas removed via a middle fossa approach and 56 removed via a retrosigmoid approach. EcochG is found to be superior in early detection of intraoperative hearing impairment, revealing deterioration due to manipulations in the internal auditory canal.