title: Gamma knife radiosurgery for symptomatic brainstem intra-axial cavernous malformations.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy and safety of gamma knife radiosurgery (GKRS) for the treatment of symptomatic brainstem intra-axial cavernous malformations (CMs) associated with high surgical morbidity.
  
  
  METHODS
  Twenty-one patients with symptomatic brainstem intra-axial CMs were treated by GKRS between 2005 and 2010. One patient was lost to follow-up. The median age of the patients was 39.5 years (range, 24-69 years). All patients had experienced 1 or more symptomatic hemorrhages before GKRS (range, 1-3). The median marginal radiation dose was 13 Gy, and the median volume of the malformation was 0.56 mL. The median follow-up period after radiosurgery was 32 months (range, 12-82 months; mean, 38.9 months).
  
  
  RESULTS
  Before GKRS, 31 hemorrhages (1.55 per patient) were observed. The annual hemorrhage rate before GKRS was 39.5%, excluding the first hemorrhage. After GKRS, 1 hemorrhage (0.05 per patient) was identified. It occurred 6 months after radiosurgery. The patient showed complete recovery to a premorbid status with steroid medication. The annual hemorrhage rate after GKRS was 8.2% for the first 2 years. After the expected latency period, no hemorrhages were identified. One patient (5%) exhibited permanent paresthesia, which was a new neurologic symptom in absence of any hemorrhagic event, after the radiosurgery.
  
  
  CONCLUSIONS
  GKRS seems to be relatively effective and safe for reducing the rebleeding rate of brainstem intra-axial CMs that have high surgical risk. Careful selection of a low marginal dose and an optimal radiosurgical technique are helpful to achieve good outcomes.
authors.affiliation: Department of Neurosurgery, Kyungpook National University Hospital, Daegu, Korea. Electronic address: nsdoctor@naver.com.
authors.forename: Seong-Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Sung-Kyoo
authors.initials: SK
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000368:Aged; D001933:Brain Stem / Q000601:surgery*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D020786:Hemangioma, Cavernous, Central Nervous System / Q000150:complications / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002538:Intracranial Arteriovenous Malformations / Q000150:complications / Q000601:surgery*; D020300:Intracranial Hemorrhages / Q000453:epidemiology / Q000209:etiology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010292:Paresthesia / Q000209:etiology; D011183:Postoperative Complications / Q000453:epidemiology / Q000628:therapy; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult