Classification of Brain Arteriovenous Malformations and Fistulas

The proper classification of brain arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs) is critical to clinical decision making and assessment of treatment risk. The Spetzler-Martin grade is the most commonly cited and rigorously tested system when evaluating outcomes following resection. Multiple additions and supplements have been made over the past two decades. The evolution of endovascular and radiosurgical therapy has driven the need for additional classifications that capture the outcomes and risks associated with these modalities. dAVFs are a diverse group of lesions with complex angioarchitecture. The Borden and Cognard systems are currently the most referenced in the classification of dAVFs. This chapter presents a review of the systems currently used to classify intracranial AVMs and dAVFs. Microsurgical, endovascular, and radiosurgical classification schemes are discussed. Special attention is paid to the most referenced systems, particularly the Spetzler-Martin grading scale for AVMs and the Borden and Cognard systems for dAVFs.