Significance of hearing preservation in acoustic neuroma surgery

In the past IO years, 43 patients with acoustic neuroma have been operated on by the middle cranial fossa approach. In all cases, meticulous care was taken to preserve the cochlear function regardless of the degree of preoper ative hearing disorder. Thirty-nine of 43 patients had various degrees of r esidual hearing; hearing was preserved in 16 of these (41%). The best resul t was obtained in patients with a tumor located less than 1 Lm from the por us. The hearing preservation rate was 64 degrees C (11/17). The patients re covered hearing acuity quite well. especially at low frequencies in 2 cases who had a pure tone hearing level of more than 50 dB and less than 50% of speech discrimination. Three 2 cases had a history of sudden deafness that was intractable 5 months preoperatively. Thus it is not correct to set cert ain criteria for hearing preservation for patients whose preoperative beari ng may not be serviceable.