RESUMO
PURPOSE OF THE STUDY: In order to investigate the role of radiosurgery and stereotactic radiotherapy in the management of vestibular schwannomas, we have reviewed our own prospective cohort and the main series of the modern literature. PATIENTS AND METHODS: Between July 14th 1992 and June 1st 2011, 2991 vestibular schwannomas were operated on the Stereotactic and Functional Neurosurgery Department of Timone University Hospital. All the patients have been evaluated prospectively, with a follow up longer than 3 years for 2336 patients, excluding patients suffering from type 2 neurofibromatosis (148 patients). In 7% of the patients, the vestibular schwannoma had previously been resected. According to Koos classification, in 17.6% of the patients, vestibular schwannomas were stage I, 51.8% stage II, 27% stage III and 3.6% stage IV. The mean tumour volume was 2.63 cm(3). According to Garner Robertson classification, the hearing was still functional at the time of radiosurgery in 46% and subnormal in 20.9% of the patients. RESULTS: Long term tumour control was achieved in 97.5% of the patients. A transient facial palsy was observed in 0.5% of the cases. The rate of trigeminal injury was 0.5%. Useful hearing was preserved at 3 years in 78%. This rate reached 95% in patients with no past history of sudden hearing loss. Other predictors of functional hearing preservation are the young age, the small size of the lesion and a dose to the modiulus of the cochlea lower than 4Gy. We observed no radio-induced tumour. Only large, Koos IV vestibular schwannomas are contraindicated for upfront radiosurgery. In these patients, we propose a combined approach with a deliberately partial microsurgical removal, followed by a radiosurgery of the residue. CONCLUSION: This cohort is unique by the size of the population and the length of the follow up and results demonstrate the efficacy of radiosurgery and its safety, especially its high rate of hearing preservation.
