Intraoperative monitoring for hearing preservation and restoration in acoustic neuroma surgery

The present article reports on our experience with hearing preservation dur ing 158 acoustic neuroma (AN) operations via the retrosigmoid-transmeatal ( RS-TM) approach with the aid of intraoperative auditory monitoring. Several auditory monitoring methods are described. Of these, the bipolar cochlear nerve action potential (CNAP) was found to be the most helpful in preservin g hearing. Of 106 patients with useful hearing pre operatively, more than 5 0% had useful hearing after surgery. Electrical auditory brainstem were use ful in the placement of an auditory brain stem implant (ABI) in 4 patients with neurofibromatosis type 2 (NF2). All 4 reported speech perception benef it and use their ABIs regularly in their lives. It is our firm belief that intraoperative auditory monitoring has a pivotal role in the preservation a nd restoration of hearing in AN surgery.