title: Retrospective analysis of a 10-year experience of stereotactic radio surgery for arteriovenous malformations in children and adolescents.
abstract: OBJECTIVE
  To obtain information essential to the decision to perform radiosurgery for arteriovenous malformations (AVMs) in children and adolescents, the authors retrospectively analyzed their experience with gamma knife surgery for AVMs in 100 patients ranging in age from 4 to 19 years.
  
  
  METHODS
  Follow-up periods ranged from 6 to 124 months (median 71 months), and the actuarial obliteration rates demonstrated by angiography were 84.1, 89.4, and 94.7% at 3, 4, and 5 years, respectively. Factors associated with better obliteration rates in univariate analysis included the following: a patient age of 12 years or younger; a mean nidus diameter of 2 cm or less; a nidus volume of 3.8 cm3 or less; a maximum diameter of the nidus less than 3 cm; and a Spetzler-Martin grade of III or less. Radiation-induced neuropathy was seen in four patients, and the risk factors were considered to be a nidus in the brainstem and a maximum radiation dose greater than 40 Gy. Hemorrhage developed during the latency interval in four patients, and one patient with a cerebellar AVM died of the hemorrhage. The annual bleeding rate was 1.5%. Feeding arteries located in the posterior cranial fossa and an AVM nidus located in the cerebellum were significantly associated with the risk of hemorrhage. After angiographically verified obliteration of the nidus, 51 patients continued to be observed from 1 to 110 months (median 67 months); hemorrhage developed in one patient 38 months after nidus obliteration.
  
  
  CONCLUSIONS
  Radiosurgery is an acceptable treatment for small AVMs in children and adolescents in whom a higher obliteration rate can be achieved with lower risks of interval hemorrhage compared with the reported results in the general population. Careful follow-up observation seems to be required, however, even after angiographically verified obliteration.
authors.affiliation: Department of Neurosurgery, University of Tokyo Hospital, Japan. shinmasa@ka2.so-net.ne.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shin
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kawamoto
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kurita
authors.forename: Masao
authors.initials: M
authors.lastname: Tago
authors.forename: Tombo
authors.initials: T
authors.lastname: Sasaki
authors.forename: Akio
authors.initials: A
authors.lastname: Morita
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ueki
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kirino
mesh_terms: D000293:Adolescent; D000328:Adult; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis / Q000601:surgery*; D008297:Male; D011183:Postoperative Complications / Q000453:epidemiology; D016634:Radiosurgery; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome