**2.1 Embolization before surgical resection**

Preoperative embolization reduces the blood loss during surgery and decreases surgery times. By decreasing the size of an AVM, the Spetzler-Martin grade and eventually surgical morbidity-mortality are decreased (**Figure 1**). Grade 1 and grade 2 AVMs, which are amenable to stand-alone surgery, may benefit from the embolization of the deeply located feeders. Grade 3 AVMs with deep and eloquent location can be treated with embolization preoperatively and surgical morbidity and mortality can be reduced significantly [22]. Presurgical embolization is the most beneficial for grade 3 AVMs.
