Gamma knife radiosurgery for intracanalicular acoustic neuromas.

In the present study we reviewed our long-term experience with radiosurgery for intracanalicular acoustic neuromas. The study involved 25 patients with unilateral intracanalicular acoustic neuromas. The treatment volume was 0.07 to 0.8 cm(3) (median: 0.27 cm(3)). The marginal radiation dose used for treatment was 12 Gy for all patients. The follow-up period ranged from 36 to 132 months (mean: 89 months). The actuarial rate of tumour growth control at 5 and 10 years after radiosurgery was 96%. Hearing preservation was achieved in 16 patients (64%) and improvement (>20 dB relative to presurgical values) was noted in one patient (4%). No patients experienced post-radiosurgery facial palsy or other cranial nerve deficits. Based on our study and long-term follow-up, radiosurgery can produce high rates of tumour growth control and hearing preservation for intracanalicular acoustic neuromas, and is an alternative to surgical resection given its low level of invasiveness. When determining treatment for intracanalicular acoustic neuromas, the condition's benign natural course and the likelihood of hearing preservation must be taken into account.