Treatment of pediatric intracranial arteriovenous malformations with linear-accelerator-based stereotactic radiosurgery: the University of Pennsylvania experience.

There are relatively few reports detailing the outcome of children and adolescents with arteriovenous malformations (AVMs) treated with stereotactic radiosurgery (SRS). We reviewed our experience over the past decade to determine whether the outcomes and toxicity were similar to those reported in adults. Seventeen patients 18 years of age or younger underwent linear-accelerator-based SRS. The targeted volume was greater than 3 cm(3) in 65% of cases (range 0.7-25 cm(3); median volume 6.9 cm(3)). The prescribed radiation doses varied from 16 to 18 Gy, with 70% receiving the highest dose. Using only angiographic data, the obliteration rate was 80% (8 of 10 patients), but using both MRA/MRI and angiographic data, it was 53% (9 of 17 patients). Four patients developed late effects potentially attributable to the radiation between 2 months and 3 years following SRS. One of these was transient and disappeared completely within a few days, but in the other 3 patients, the neurologic sequelae were permanent. Two of the 4 complications appeared to be due to radiation necrosis/edema, whereas the remaining 2 may have been due to vasculopathy. All 4 patients with complications had treatment volumes greater than 5 cm(3) (5.4, 6.9, 11.1, 16.4 cm(3)), all had a prescribed dose of 18 Gy and all had initially presented with an AVM hemorrhage. Linear-accelerator-based SRS is effective in obliterating most AVMs in children; however, the potential for late effects exists, especially for those patients with larger target volumes.