• Christian Iorio-Morin, Fahd AlSubaie, and David Mathieu.
• *Neurosurgery Division, Université de Sherbrooke, Centre Hospitalier Universitaire de Sherbrooke, Centre de Recherche du CHUS, Sherbrooke, Quebec, Canada; ‡Saudi National Neuroscience Institute, Riyadh, Saudi Arabia.
• Neurosurgery. 2016 Apr 1; 78 (4): 521-30.

BackgroundGamma Knife radiosurgery (GKRS) is commonly used in treating small vestibular schwannomas; however, its use for larger vestibular schwannomas is still controversial.ObjectiveTo assess the long-term safety and efficacy of treating eligible Koos grade 4 vestibular schwannomas with GKRS.MethodsWe conducted a single-center, retrospective evaluation of patient undergoing GKRS for Koos grade 4 vestibular schwannomas. We evaluated clinical, imaging, and treatment characteristics and assessed treatment outcome. Inclusion criteria were tumor size of ≥4 cm and follow-up of at least 6 months. Patients with neurofibromatosis type 2 were excluded. Primary outcomes measured were tumor control rate, hearing and facial function preservation rate, and complications. All possible factors were analyzed to assess clinical significance.ResultsSixty-eight patients met inclusion criteria. Median follow-up was 47 months (range, 6-125 months). Baseline hearing was serviceable in 60%. Median tumor volume at radiosurgery was 7.4 cm (range, 4-19 cm). The median marginal dose used was 12 Gy at the 50% isodose line. Actuarial tumor control rates were 95% and 92% at 2 and 10 years, respectively. Actuarial serviceable hearing preservation rates were 89% and 49% at 2 and 5 years, respectively. Facial nerve preservation was 100%. Clinical complications included balance disturbance (11%), facial pain (10%), facial numbness (5%), and tinnitus (10%). Most complications were mild and transient. Hydrocephalus occurred in 3 patients, requiring ventriculoperitoneal shunt insertion. Larger tumor size was significantly associated with persisting symptoms post-treatment.ConclusionPatients with Koos grade 4 vestibular schwannomas and minimal symptoms can be treated safely and effectively with GKRS.AbbreviationsGKRS, Gamma Knife radiosurgeryVS, vestibular schwannoma.

19 keywords...

hide…