Study of Dural Arteriovenous Fistula Drains into Leptomeningeal Vein without Sinus Interposition.

We evaluated dural arteriovenous fistulas (DAVF) drains into leptomeningeal vein (LMV) without the venous sinus interposition. This type of DAVF contained the extra-sinusal type DAVF and the DAVF with so-called pure leptomeningeal venous drainage (PLMVD).We studied 15 patients with DAVF that flows into LMVD without passing into the sinus. The subjects were 5 patients with DAVF in the anterior cranial fossa, 2 with DAVF in the tentorium cerebelli, and 3 with DAVF in the craniocervical junction as extra-sinusal type DAVF and 3 with DAVF in the transverse sigmoid sinus and 2 with DAVF in the superior sagittal sinus as DAVF with PLMVD. This type appears to take a very aggressive course. The arterial pressure of the shunt is directly applied to LMV, which causes bending and winding of the vein, eventually varices, inducing intracranial haemorrhage or venous ischemia in the LMV reflux area. Emergency treatment should be performed as soon as possible. Although it is recognized that interruption of the draining vein is very effective, treatment methods such as TAE, direct surgery, and g knife treatment, or their combinations should be carefully chosen for each case.