Is preservation of hearing in acoustic neuroma worthwhile?

In a series of 300 translabyrinthine removals of acoustic neuromas, comprising almost all tumours operated on in Denmark during a period of 10 years, the preoperative hearing in the tumour ear and in the contralateral ear was analysed in 72 patients with tumours smaller than 2 cm in extrameatal diameter. These patients constitute likely candidates for a hearing preserving operation via the suboccipital approach. In the tumour ear in 4 patients there was a pure-tone average (PTA) of 0-20 dB and a discrimination score (DS) of 81-100%. Applying this criterion to the whole series, 1% of the patients would be candidates for a hearing preserving procedure. Changing the criterion to a PTA of 0-40 dB and a DS of 61-100%, the number of candidates would increase to 8 patients (3%), and with a PTA of 0-50 dB and a DS of 51-100% 14 candidates (5%) would have been found. In all of these patients, contralateral hearing was normal (SRT 0-20 dB, DS 95-100%). Since preservation of hearing would be achieved in only half of those subjected to suboccipital removal and since the hearing retained in patients with successful operations is generally poorer than the preoperative level, the number of patients obtaining serviceable hearing is so modest that preservation of hearing cannot be considered an argument in favour of suboccipital tumour removal. It should be borne in mind that contralateral hearing is normal in these patients and that, according to most reports, the mortality rate is higher and paralysis of the facial nerve more frequent with the suboccipital approach than with the translabyrinthine procedure.