title: Radiosurgery for symptomatic cavernous malformations: A multi-institutional retrospective study in Japan.
abstract: BACKGROUND
  A group study for symptomatic cavernous malformation (CM) treated with gamma knife (GK) surgery was performed.
  
  
  METHODS
  A total of 298 cases collected from 23 GK centers across Japan were included. Hemorrhage was the most common manifestation, followed by seizures and neurological deficits. Most of the lesions were located in the brainstem and basal ganglia, followed by the cerebral or cerebellar hemispheres. The CMs, which had a mean diameter of 14.8 mm, were treated using GK surgery with a mean marginal dose of 14.6 Gy.
  
  
  RESULTS
  In terms of hemorrhage-free survival (HFS), a marked dissociation was confirmed between the hemorrhage and seizure groups, while no obvious difference was noted between sexes. Superficial CMs located in cerebellum or lobar regions responded to the treatment better than deeply located CMs in the basal ganglia or brainstem. No significant difference of dose-dependent response was seen for three different ranges of marginal dose: Less than 15 Gy, between 15 and 20 Gy, and more than 20 Gy. Complications were more frequent after a marginal dose of over 15 Gy and in patients with lesions more than 15 mm in diameter. The rates of annual hemorrhage were estimated to be 7.4% during the first 2 years after radiosurgery and 2.8% thereafter. The overall hemorrhage rate after radiosurgery was 4.4%/year/patient.
  
  
  CONCLUSIONS
  The risk of hemorrhage is considerably reduced after GK treatment. The HFS as well as annual hemorrhage rate after GK treatment was apparently superior to that after conservative treatment for symptomatic CMs. To optimize the success of GK treatment, it is important to reduce the incidence of complications.
authors.affiliation: Department of Neurosurgery, General Kamiiida Daiichi Hospital, Scientific Committee of Japanese Gamma Knife Society, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kida
authors.affiliation: Department of Neurosurgery, Komaki City Hospital, Scientific Committee of Japanese Gamma Knife Society, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Department of Neurosurgery, Osaka General Medical Center, Scientific Committee of Japanese Gamma Knife Society, Japan.
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Iwai
authors.affiliation: Department of Neurosurgery, Yokohama Rosai Hospital, Scientific Committee of Japanese Gamma Knife Society, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shuto
authors.affiliation: Department of Neurosurgery, Rakusai Shimizu Hospital, Scientific Committee of Japanese Gamma Knife Society, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Satoh
authors.affiliation: Department of Neurosurgery, Shinsuma General Hospital, Scientific Committee of Japanese Gamma Knife Society, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kondoh
authors.affiliation: Department of Neurosurgery, Tokyo Women's Medical University, Scientific Committee of Japanese Gamma Knife Society, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Hayashi
keywords: Cavernous malformation; gamma knife; radiosurgery; symptomatic lesion; vascular anomaly