Endovascular Treatment of Spetzler-Martin Grade III Arteriovenous Malformations: A Single-Center 12 years' Experience Stratified by the Spetzler-Martin Modified Scale

Background and objectives: Limited evidence exists for endovascular first-line treatment of Spetzler-Martin (SM) grade III brain arteriovenous malformations (AVMs). In this article, we sought to evaluate advanced endovascular techniques for treating SM III AVMs across different sizes, eloquence, and patterns of venous drainage.

Methods: Data from AVMs SM III treated between January 2010 and January 2022 were collected: size (S), eloquence (E), drainage (V), angioarchitecture features (arterial and venous aneurysms, venous drainage, and venous stenosis), treatment strategy (single arterial, double arterial, venous, both arterial and venous, and transvenous endovascular embolization with selective temporary flow arrest [TFATVE]), neoadjuvant treatment, and number of previous embolization sessions. AVMs were classified according to the modified SM grade as follows: small (S1V1E1/III-), medium/deep (S2V1E0/III), medium/eloquent (S2V0E1/III+), and large (S3V0E0). Treatment complications (hemorrhagic and ischemic), clinical discharge and 6-month outcomes (modified Rankin Scale 0-2, mRS), and angiographic occlusion rates were recorded.

Results: A total of 91 AVMs (62.6% ruptured, 72.5% S1V1E1, 7% S2V1E0, 19.7% S2V0E1, and 0% S3V0E0) in 91 patients (mean age 37 ± 15.8 years) were included. Treatment techniques included single arterial approach (28.6%), double arterial technique (30.8%), single venous strategy (9.9%), TFATVE (10.9%), and arterial and venous combined (19.8%). The angiographic occlusion rate was 91.2% (90.9% S1V1E1, 100% S2V1E0, and 88.9% S2V0E1) for all techniques, and 100% for the transvenous technique, isolated or combined with transarterial embolization. Minor complication (mRS 0-2), major complication (mRS >2), and mortality rate were 16.5%, 2.2%, and 3.4%, respectively. Overall, treatment morbimortality (mRS >2) was 3% (2/66) for S1V1E1, 0% for S2V1E0, and 16.7% (3/18) for S2V0E1.

Conclusion: Although morbidity is non-negligible , endovascular treatment of SM grade III lesions with advanced techniques offers up to 100% rates of cure, which is of high interest, especially for ruptured deep-seated eloquent AVMs with high reruptured rates, and less amenable to microsurgery techniques.