Spetzler-Martin Research Articles

Surgical interventions in intracranial arteriovenous malformations: Indications and outcome analysis in a changing scenario

Intracranial arteriovenous malformations (AVM) are being increasingly managed by multimodality approach. This changing scenario encouraged us to study the present state of surgery in intracranial AVMs and the outcomes. Of a total of 868 patients evaluated for suspected or known AVMs between January 2000 and July 2008, 790 had intracranial AVMs. The clinical characteristics and surgical outcomes of the 111 operated patients were analyzed. Of the 111 patients, 73 were males. Clinical features included: Headache (70%), loss of consciousness (48%) and seizures (32%). The commonest AVM grade was Spetzler-Martin (SM) grade II (41%), 7% had AVM > 6 cm and 78% had evidence of bleed. In total 143 surgeries were performed and 22% of patients required multiple interventions. The types of surgical interventions included elective excision of AVM in 23%, emergency surgery (either AVM excision or evacuation of hematoma) in 55%, surgery following radiosurgery/embolization in 5% and palliative non-definitive surgeries (e.g. shunt) in 15%. Post-operative angiography was done in 67% of patients. Obliteration rates for elective excision of AVM in Spetzler Martin Grade I, II, IIIa, IIIb and IV were 100%, 71%, 33%, 50% and 67% respectively (mean follow-up:31.6 months). Of 39 patients with residual AVMs, 33 received gamma knife and four underwent embolization. Outcome was modified Rankin scale (mRS) grade 1 in 34% of patients and the overall favorable outcome was 83% and there were six deaths. In our patients' cohort one in every eight patients required surgery. In intracranial AVMs, surgery still plays an important role. In developing countries like India it may be beneficial to electively excise Grade I and II AVMs if cost is a consideration.

Prognostic Factors for Complete Obliteration of Arteriovenous Malformations Treated with LINAC-Based Stereotactic Radiosurgery

Few series analyzing prognostic fac tors predicting for obliteration of arteriovenous malformations (AVMs) following linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) have been reported. We analyzed prognostic variables, outcomes, and toxicities in 88 patients undergoing LINAC-based SRS for AVMs. Following IRB approval, patient records were retrospectively analyzed to identify independent predictors of complete response (obliteration) (CR) and time-to-CR. The majority of AVMs were treated using multiple isocenters and non-coplanar arcs. The median AVM volume was 2.67 cm3 (0.05 - 33.51). Median marginal and maximal doses were 17 (12-24) and 26.1 Gy (15-40), with a median prescription isodose surface of 65%. Spetzler-Martin (SM) grade was determined for 86 patients and was: I-3 pts (3%); II-23 pts (27%); III-45 pts (52%); IV-13 pts (15%); V-2 pts (2%).Of 80 patients with follow-up imaging, 44 (55%) had documented complete responses (CR). Kaplan-Meier estimate probability for CR at 4 years was 62% (95% CI: 0.50, 0.74). Median time to CR was 3 years (95% CI: 2.08, 3.17). Multivariate analysis demonstrated the Spetzler-Martin grade (OR=0.14 for grade III vs. grade I-II; p=0.004 and OR 0.07 for grade IV-V vs. grade I-II; p=0.002) and dichotomized marginal dose > 17 Gy (OR=4.19; p=0.01) to be significantly associated with CR. This report demonstrates that for LINAC-based SRS of AVM, marginal dose and Spetzler-Martin grade are strong predictors of complete AVM obliteration.