Surgical interruption of leptomeningeal drainage as treatment for intracranial dural arteriovenous fistulas without dural sinus drainage

Abstract

Intracranial dural arteriovenous fistulas (AVFs) have been recognized as acquired lesions that can behave aggressively depending on the pattern of venous drainage. Based on the type of venous drainage, they can be classified as fistulas drained only by venous sinuses, those drained by venous sinuses with retrograde flow in arterialized leptomeningeal veins, and fistulas drained solely by arterialized leptomeningeal veins. Serious symptoms, including hemorrhage and focal deficit, are related to the presence of arterialized leptomeningeal veins. In this paper, the authors report a consecutive series treated between 1988 and 1993 of 20 cases of intracranial dural AVFs with "pure leptomeningeal drainage." All patients underwent surgical interruption of the leptomeningeal draining veins. Based on the arterial supply, nine patients were managed by direct surgery, whereas 11 patients were prepared for surgery by means of preoperative arterial embolization. Radioanatomical cure of the fistula and good neurological recovery were achieved in 18 cases. Complete obliteration of the fistula was documented angiographically in two cases, but fatal hemorrhage occurred, probably due to partial thrombosis of the venous drainage. Based on this experience, the authors believe that surgical interruption of the draining veins is the best treatment option for intracranial dural AVFs. However, surgical results may be affected by the extension of postoperative thrombosis, which in turn may be related to the degree of preoperative venous engorgement.