Classification of spontaneous dural arteriovenous fistulas with regard to their pathogenesis.

PURPOSE: A classification of dural arteriovenous fistulas (DAVFs) according to their pathogenesis has not been established. The purpose of this study was to examine the hypothesis that the different angiomorphologies of DAVFs depend on the location of the venous recipient, and that a territorial classification of spontaneous DAVFs can be created based on their acquired development.

MATERIAL AND

METHODS

The clinical and radiographic findings of 96 patients with DAVFs were reviewed, especially with regard to their venous characteristics.

RESULTS

DAVFs were 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 Galen'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 location of the DAVF: in 72% of the cases with type 1 DAVFs there was a thrombosis at the time of the investigation, but no thrombosis could be proved in cases with type 4 DAVFs.

CONCLUSION

The morphological development of DAVFs seems to depend on the flow volume of the venous recipient. A pronounced development of pathological AV shunts takes place at the level of the large basal dural sinuses. A delayed development of pathological AV shunts with a low shunt volume occurs in a venous recipient with a low AV pressure gradient.