Results in otosurgically treated patients with acoustic neuroma - Part 2: Hearing results after middle fossa approach

Background: The surgical therapy of acoustic neuromas has been seen critically lately. Alternative methods like the gamma-knife treatment open a wide field of discussion. Patients: The results of 392 patients are presented operated on via a middle fossa approach between 1989 and 2004. Results: Hearing preservation according to the 50: 50 rule (hearing loss less than 50 dB in pure tone audiogram 500 1000 - 2000 Hz, speach discrimination > 50%) was possible in 59.7% of patients. A hearing impression up to 90 dB was recognized in 83.1%,16.9% of cases were deaf. There was no difference between tumors confined to the inner ear canal and tumors extending into the cerebello pontine angle. There was also no difference between tumors up to a volume of 100 mm(3) and tumors between 100 mm(3) and 500 mm(3). Conclusion: Acoustic neuroma confined to the internal meatus or with little extend into the cerebello pontine angle (i.e. no contact to structures of the brain stem or vessels of the posterior fossa) are feasable for resection via the middle fossa approach. The possibility of hearing preservation and low morbidity makes it the treatment of choice for this group of tumors.