Stereotactic radiosurgery for Spetzler-Martin Grade III arteriovenous malformations.
OBJECTIVE
The purpose of this study was to define the outcomes and risks of stereotactic radiosurgery (SRS) for Spetzler-Martin (SM) Grade III arteriovenous malformations (AVMs).


METHODS
Between 1987 and 2009, SRS was performed in 474 patients with SM Grade III AVMs. The AVMs were categorized by scoring the size (S), drainage (D), and location (L): IIIa was a small AVM (S1D1L1, N = 282); IIIb was a medium/deep AVM (S2D1L0, N = 44); and IIIc was a medium/eloquent AVM (S2D0L1, N = 148). The median target volume was 3.8 ml (range 0.1-26.3 ml) and the margin dose was 20 Gy (range 13-25 Gy). Eighty-one patients (17%) underwent prior embolization, and 58 (12%) underwent prior resection.


RESULTS
At a mean follow-up of 89 months, the total obliteration rates documented by angiography or MRI for all SM Grade III AVMs increased from 48% at 3 years to 69% at 4 years, 72% at 5 years, and 77% at 10 years. The SM Grade IIIa AVMs were more likely to obliterate than other subgroups. The cumulative rate of hemorrhage was 2.3% at 1 year, 4.4% at 2 years, 5.5% at 3 years, 6.4% at 5 years, and 9% at 10 years. The SM Grade IIIb AVMs had a significantly higher cumulative rate of hemorrhage. Symptomatic adverse radiation effects were detected in 6%.


CONCLUSIONS
Treatment with SRS was an effective and relatively safe management option for SM Grade III AVMs. Although patients with residual AVMs remained at risk for hemorrhage during the latency interval, the cumulative 10-year 9% hemorrhage risk in this series may represent a significant reduction compared with the expected natural history.
Departments of Neurological Surgery and.
Hideyuki
H
Kano
John C
JC
Flickinger
Huai-che
HC
Yang
Thomas J
TJ
Flannery
Daniel
D
Tonetti
Ajay
A
Niranjan
L Dade
LD
Lunsford
D000293:Adolescent; D000328:Adult; D000368:Aged; D002533:Cerebral Angiography; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D013238:Stereotaxic Techniques / Q000009:adverse effects*; D016896:Treatment Outcome