title: Long-term results of Gamma-knife stereotactic radiosurgery for vestibular schwannomas in patients with type 2 neurofibromatosis.
abstract: BACKGROUND
  The aim of this study was to analyze the long-term results of Gamma-knife radiosurgery treatment of vestibular schwannomas in type 2 neurofibromatosis patients.
  
  
  METHODS
  A cohort of 129 treatments for vestibular schwannomas in 103 patients was selected from a prospectively-maintained clinical database. Tumor control was assessed by volumetric analysis of the tumor at the last follow-up. Any need of a further procedure such as microsurgical removal or second treatment was regarded as a failure of tumor control. Hearing function was assessed based on Gardner-Robertson classification. Progression-free survival and functional hearing preservation rates were estimated using the Kaplan-Meier method.
  
  
  RESULTS
  The median age at treatment was 34 years with no gender predominance. The median tumor volume was 1.5cm3. At a median clinical follow-up of 5.9 years, five patients had died, four underwent a second radiosurgical procedure and eight underwent microsurgical resection. Progression-free survival was 88 and 75% respectively at 5 and 10 years. Hearing was considered serviceable in 70 ears and remained functional in 28 ears. Kaplan-Meier estimates for 5 and 10 years functional hearing was 47 and 34%, respectively. Three patients developed new facial nerve palsy after radiosurgery at 15 days, 6 and 19 months respectively and only one partially recovered. Five patients complained of a subjective instability worsening. Four cases developed trigeminal neuropathy. No predictive factors were found to be statistically correlated with a better hearing outcome or an improved tumor growth control.
  
  
  CONCLUSIONS
  Results prove less satisfying than in sporadic unilateral schwannomas. However, the lower rate of mortality and morbidity compared with microsurgical resection may support a proactive role of Gamma-knife in this pathology.
authors.affiliation: Inserm U751, Department of Functional and Stereotactic Neurosurgery Unit, centre hospitalier universitaire La Timone Assistance publique-Hôpitaux de Marseille, Aix Marseille University, 13385 Marseille, France; Department of Neurosurgery and Stereotactic Radiosurgery, Division of Neuroscience, IRCCS Ospedale San Raffaele, 20132 Milan, Italy. Electronic address: giorgio.spatola@gmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Spatola
authors.affiliation: Inserm U751, Department of Functional and Stereotactic Neurosurgery Unit, centre hospitalier universitaire La Timone Assistance publique-Hôpitaux de Marseille, Aix Marseille University, 13385 Marseille, France.
authors.forename: R
authors.initials: R
authors.lastname: Carron
authors.affiliation: Inserm U751, Department of Functional and Stereotactic Neurosurgery Unit, centre hospitalier universitaire La Timone Assistance publique-Hôpitaux de Marseille, Aix Marseille University, 13385 Marseille, France.
authors.forename: C
authors.initials: C
authors.lastname: Delsanti
authors.affiliation: Department of ENT, centre hospitalier universitaire La Timone Assistance Publique-Hôpitaux de Marseille, Aix Marseille University, 13385 Marseille, France.
authors.forename: J-M
authors.initials: JM
authors.lastname: Thomassin
authors.affiliation: Department of Neurosurgery, centre hospitalier universitaire hôpital Nord, Assistance Publique-Hôpitaux de Marseille, Aix Marseille University, 13915 Marseille, France.
authors.forename: P-H
authors.initials: PH
authors.lastname: Roche
authors.affiliation: Inserm U751, Department of Functional and Stereotactic Neurosurgery Unit, centre hospitalier universitaire La Timone Assistance publique-Hôpitaux de Marseille, Aix Marseille University, 13385 Marseille, France.
authors.forename: J
authors.initials: J
authors.lastname: Régis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009442:Neurilemmoma / Q000601:surgery*; D016518:Neurofibromatosis 2 / Q000601:surgery*; D009464:Neuroma, Acoustic / Q000601:surgery; D016634:Radiosurgery / Q000379:methods; D016896:Treatment Outcome; D047368:Tumor Burden / Q000502:physiology; D055815:Young Adult
keywords: Gamma-knife; Gardner-Robertson; Hearing function; Radiosurgery; Type 2 neurofibromatosis; Vestibular schwannoma