Table 2

Revised classification of Djinjian and Merland

Type I: DAVF draining into a sinus, with a normal antegrade flow direction
Type II: DAVF draining into a sinus. Insufficient antegrade venous drainage and reflux. The insufficiency of the venous drainage may be due to stenosis or occlusion of the sinus draining a moderate flow rate DAVF, or to a very high flow rate DAVF which cannot be drained by a normal or even enlarged sinus. Depending on the retrograde venous drainage, three subtypes are distinguished:
 Type IIa: retrograde venous drainage into sinus(es) only
 Type IIb: retrograde venous drainage into cortical vein(s) only
 Type IIa+b: retrograde venous drainage into sinus(es) and cortical vein(s)
Type III: DAVFs draining directly into a cortical vein without venous ectasia
Type IV: DAVFs draining into a cortical vein with a venous ectasia >5 mm in diameter and three times larger than the diameter of the draining vein.
Type V: DAVFs (intracranial) draining into spinal perimedullary veins