Management of vestibular schwannomas: current state of the art

ABSTRACT

Vestibular schwannomas [VS] have always been a great challenge for neurosurgeons. The evolution of surgical management of VS is parallel of the history of the development of modem neurosurgery. Gamma knife surgery [GKS] is becoming a standard treatment for small or middle size VS while microsurgery remains the effective treatment of the large tumours. The combinations of the two techniques offer a big chance to preserve facial function in Koos IV VS. The Marseille SRS experience includes 2150 patients, with more than 1000 patients having follow-up longer than 3 years. In this series the Koos classification was stage I 9%, stage II 55.5%, stage III 287 31% and stage IV 4.5%. The average volume was 12.7 mm[3]. Heating was useful [Gardner and Robertson] before radiosurgery in 47% of the patients [subnormal in 20.3%].A long-term tumour control rate of 97%. Globally, a clinical trigeminal injury was observed in 0.6% of the patients and transient facial palsy lower than 1%. There was clearly a decrease of the incidence of neuropathies with time, and a probability of functional hearing preservation between 50 and 95%, depending on preoperative parameters, was achieved in this large series of patients treated by state-of-the-art GKS. Other parameters such as long-term complications, type 2 neurofibromatosis, the influence of tumour characteristics and the treatment of the residual or recurrent VS after microsurgery are reviewed and detailed. Today, strong evidence supports the superiority of GKS in terms of functional preservation and equal efficacy compared with microsurgical removal. Consequently, radiosurgery must be preferred as a first intention choice for young patients with few symptoms presenting with a small to middle size VS [Koos I to Ill]. Only large Koos IV remained first line indication for microsurgery. The combined approach should provide these patients with a major reduction of risks, particularly in terms of rate of facial palsy