Radiosurgery for Large Arteriovenous Malformations as a Single-Session or Staged Treatment.
OBJECTIVE
The treatment of large arteriovenous malformations (AVMs) presents a challenge and the effectiveness of radiosurgery decreases with increasing treatment volume. Here, we analyzed and compared single-session treatment for AVMs >15 cm3 with staged treatment, when the volume of a large AVM was divided into 2 or more compartments, which were subsequently treated at intervals of a few months. In the event that complete obliteration was not achieved within 3 years, repeat radiosurgery was considered.


RESULTS
Between 1993 and 2011, gamma-knife radiosurgery was performed on 50 patients with large AVMs. A total of 27 of them, with volumes ranging from 15.1 to 27 cm3 (median = 17.8), were treated in a single session, with a marginal dose ranging from 10 to 17 Gy (median = 15). Complete obliteration was achieved in 7 (26%) of these; in 14 patients the treatment was repeated after a median of 38 months. The volume of AVMs subjected to repeat treatment regressed and ranged from 6.76 to 16.4 cm3 (median = 7.7), with the marginal dose ranging from 13 to 18 Gy (median = 17); 10 patients later achieved complete obliteration at a median of 79 months after the initial treatment. Overall, 63% of patients achieved complete obliteration of AVM after treatment. Rebleeding in a latent period was recorded in 3 patients (11%) and symptomatic collateral edema in 2 (7%); 23 patients were treated using the staged method, with the interval between staged treatments usually being 6 months. Their overall AVM volume ranged from 13.2 to 46.6 cm3 (median = 23.3), the volume for a single stage ranged from 4.5 to 31.3 cm3 (median 11.7), and the marginal dose ranged from 10 to 18 Gy (median = 17). Complete obliteration was achieved in 4 (17%) of them, in 8 patients the treatment was repeated at a median of 53 months after the first treatment, and a third retreatment was performed on 2 patients 98 and 102 months, respectively, after the first treatment. The volume for repeated treatment of AVMs ranged from 0.81 to 7.7 cm3 (median = 3.3), with the marginal dose ranging from 14 to 20 Gy (median 17.5). Of all the retreated patients, 5 AVMs subsequently achieved complete obliteration. Overall, 9 patients (39%) were totally cured. Rebleeding in a latent period was observed in 1 of these patients (4.3%) and symptomatic edema in another 1 (4.3%).


CONCLUSIONS
Radiosurgery of large AVMs is a valuable treatment either as a single-session or staged treatment, with a reasonable chance of cure and a low risk of complications.
Department of Stereotactic and Radiation Neurosurgery, Na Homolce Hospital, Prague, Czech Republic.
Tomas
T
Chytka
Roman
R
Liscak
Petra
P
Kozubiková
Josef
J
Vymazal
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult