Classification schemes for arteriovenous malformations.

The wide variety of arteriovenous malformation (AVM) anatomy, size, location, and clinical presentation makes patient selection for surgery a difficult process. Neurosurgeons have identified key factors that determine the risks of surgery and then devised classification schemes that integrate these factors, predict surgical results, and help select patients for surgery. These classification schemes have value because they transform complex decisions into simpler algorithms. In this review, the important grading schemes that have contributed to management of patients with brain AVMs are described, and our current approach to patient selection is outlined.