title: Stereotactic radiosurgery for the treatment of symptomatic brainstem cavernous malformations.
abstract: OBJECTIVE
  The authors performed a retrospective review of prospectively collected data to evaluate the safety and efficacy of stereotactic radiosurgery (SRS) for the treatment of patients harboring symptomatic solitary cavernous malformations (CMs) of the brainstem that bleed repeatedly and are high risk for resection.
  
  
  METHODS
  Between 1988 and 2005, 68 patients (34 males and 34 females) with solitary, symptomatic CMs of the brainstem underwent Gamma Knife surgery. The mean patient age was 41.2 years, and all patients had suffered at least 2 symptomatic hemorrhages (range 2-12 events) before radiosurgery. Prior to SRS, 15 patients (22.1%) had undergone attempted resection. The mean volume of the malformation treated was 1.19 ml, and the mean prescribed marginal radiation dose was 16 Gy.
  
  
  RESULTS
  The mean follow-up period was 5.2 years (range 0.6-12.4 years). The pre-SRS annual hemorrhage rate was 32.38%, or 125 hemorrhages, excluding the first hemorrhage, over a total of 386 patient-years. Following SRS, 11 hemorrhages were observed within the first 2 years of follow-up (8.22% annual hemorrhage rate) and 3 hemorrhages were observed in the period after the first 2 years of follow-up (1.37% annual hemorrhage rate). A significant reduction (p < 0.0001) in the risk of brainstem CM hemorrhages was observed following radiosurgical treatment, as well as in latency period of 2 years after SRS (p < 0.0447). Eight patients (11.8%) experienced new neurological deficits as a result of adverse radiation effects following SRS.
  
  
  CONCLUSIONS
  The results of this study support a role for the use of SRS for symptomatic CMs of the brainstem, as it is relatively safe and appears to reduce rebleeding rates in this high-surgical-risk location.
authors.affiliation: Department of Neurological Surgery and the Center for Image-Guided Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Monaco
authors.forename: Aftab A
authors.initials: AA
authors.lastname: Khan
authors.forename: Ajay
authors.initials: A
authors.lastname: Niranjan
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.forename: Ramesh
authors.initials: R
authors.lastname: Grandhi
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.forename: John C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
mesh_terms: D000328:Adult; D001933:Brain Stem / Q000473:pathology / Q000601:surgery*; D020295:Brain Stem Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D002543:Cerebral Hemorrhage / Q000175:diagnosis / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D020786:Hemangioma, Cavernous, Central Nervous System / Q000175:diagnosis / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome