**2. Endovascular treatment**

The first report of embolization of an AVM was published by Luessenhop and Spence et al. in 1960 [18] who used methyl methacrylate pellets after a direct carotid puncture. Selective catheterization of the intracranial circulation with microcatheters was first described by Serbinenko et al. [19] and Kerber. Further evolution has occurred with the use of new liquid embolic agents like cyanoacrylate by Drake et al. [20] and Debrun et al. [21]. After years of embolization with N-butyl cyanoacrylate, introduction of a new agent composed of ethylene vinyl alcohol polymer (Onyx, Medtronic, Irvine, CA, USA) has changed the practice of AVMs once more.

Endovascular treatment of cerebral AVMs can be used before open surgery, before radiosurgery, for cure as a stand-alone treatment, to target the weak angioarchitectural points, or for palliative purposes. The advantages of endovascular treatment include minimally invasiveness, immediate angiographic evaluation during and after the treatment, and immediate occlusive effect. Angiography is the gold standard for the diagnosis and treatment planning for AVMs. Angiograms show the location, size, and number of arterial feeders and draining veins and locate weak points such as intranidal aneurysms, flow-related aneurysms, venous drainage stenosis, ectasia, or aneurysm of the draining veins. These angioarchitectural characteristics lead to decision on the treatment strategy for a specific AVM including surgical, endovascular, or radiosurgical techniques.
