title: Gamma knife surgery for pediatric arteriovenous malformations: a 25-year retrospective study.
abstract: OBJECTIVE
  The authors present their 25-year experience in treating pediatric arteriovenous malformations (AVMs) to allow comparisons with other historic studies and data in adults.
  
  
  METHODS
  Data were collected from a prospectively maintained departmental database selected for age and supplemented by case note review and telephone interviews as appropriate.
  
  
  RESULTS
  Three hundred sixty-three patients, ages 1-16 years (mean ± SD, 12 ± 3.2 years), underwent 410 treatments; 4 had planned 2-stage treatments and 43 were retreated subsequent to an initial partial response. Fifty-eight percent received general anesthesia for the procedure. Sixteen percent had previously undergone embolization. The most common presenting symptoms were as follows: hemorrhage (80.2%), epilepsy (8.3%; overall seizure prevalence 19.9%), and migrainous headaches (6.3%). Only 0.28% of the AVMs were incidental findings. The mean lesion volume was 3.75 ± 5.3 cm3 (range 0.01-32.8 cm3), with a median Spetzler-Martin grade of III (range I-V). The mean peripheral (therapeutic) dose was 22.7 ± 2.3 Gy (range 15-25 Gy), corresponding to a mean maximum dose of 43.6 ± 6 Gy (range 25-51.4 Gy). The obliteration rate was 71.3% in patients who received one treatment and 62.5% for retreated patients, with a mean obliteration time of 32.4 and 79.6 months, respectively. The overall obliteration rate was 82.7%. No follow-up data are as yet available for the 4 patients who underwent the staged treatments. Only 4 patients received peripheral doses below 20 Gy, and the AVM was obliterated in 3 of these patients. The other patients received 20, 22.5, or 25 Gy and had obliteration rates of 82.6%, 77.7%, and 86.3%, respectively. The bleeding rate postradiosurgery was 2.2%, and the cumulative complication rate was 3.6%, with radionecrosis being the most common complication (1.1%).
  
  
  CONCLUSIONS
  Surprisingly, there was no correlation (p = 0.43) between outcome and radiosurgical dose when that dose was between 20 and 25 Gy, thus suggesting that the lower of these 2 doses may be effective. Radiosurgery for pediatric AVM is safe and effective.
authors.affiliation: National Centre for Stereotactic Radiosurgery, Royal Hallamshire Hospital, Sheffield, UK.
authors.forename: Eduard B
authors.initials: EB
authors.lastname: Dinca
authors.forename: Patricia
authors.initials: P
authors.lastname: de Lacy
authors.forename: John
authors.initials: J
authors.lastname: Yianni
authors.forename: Jeremy
authors.initials: J
authors.lastname: Rowe
authors.forename: Matthias W R
authors.initials: MW
authors.lastname: Radatz
authors.forename: Daniel
authors.initials: D
authors.lastname: Preotiuc-Pietro
authors.forename: Andras A
authors.initials: AA
authors.lastname: Kemeny
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery*; D016634:Radiosurgery; D012189:Retrospective Studies; D013997:Time Factors