CLASSIFICATION OF SPONTANEOUS DURAL ARTERIOVENOUS-FISTULAS WITH REGARD TO THEIR PATHOGENESIS

Purpose. A classification of dural arteriovenous fistulas (DAVFs) acco rding to their pathogenesis has not been established. The purpose of t his study was to examine the hypothesis that the different angiomorpho logies of DAVFs depend on the location of the venous recipient, and th at a territorial classification of spontaneous DAVFs can be created ba sed on their acquired development. Material and Methods. The clinical and radiographic findings of 96 patients with DAVFs were reviewed, esp ecially with regard to their venous characteristics. Results: DAVFs we re subdivided into 5 groups: Type 1 - DAVFs of the dural sinuses (n=39 ); Type 2 - DAVFs of the cavernous sinus (n=29); Type 3 - DAVFs of Gal en's system (n=10); Type 4 - DAVFs of the venous plexus at the base of the skull (n=9); Type 5 - DAVFs of the parasinusal cortical veins (n= 9). The documentation of a causal sinus thrombosis depends on the loca tion of the DAVF: in 72% of the cases with type 1 DAVFs there was a th rombosis at the time of the investigation, but no thrombosis could be proved in cases with type 4 DAVFs. Conclusion. The morphological devel opment of DAVFs seems to depend on the flow volume of the venous recip ient. A pronounced development of pathological AV shunts takes place a t the level of the large basal dural sinuses. A delayed development of pathological AV shunts with a low shunt volume occurs in a venous rec ipient with a low AV pressure gradient.