Reflections upon the nature and management of intracranial and intraspinal vascular malformations and fistulae

Abstract

Evidence is presented that dural fistulae are preceded by sinus thrombosis and that their danger lies in arterialized venous pressure within the cranium or the orbit. Arterial side occlusion leads to recurrence, while venous side occlusion leads to permanent cure. Vein of Galen aneurysms embrace some features of cerebral arteriovenous malformations (AVM's), namely a reticulum, and some features of dural fistulae, namely evidence of previous sinus anomaly and direct drainage into a sinus. These aneurysms are also permanently cured by venous side thrombosis, although the dangers inherent in their reticulum demand that this be done in stages or preceded by arterial side embolization. A very limited experience with venous end occlusion of cerebral (and spinal) AVM's suggests that they, too, can be permanently cured by venous side occlusion without excision. Their reticulum demands maximum, multistage, preliminary arterial side embolization together with intraoperative hypotension during the venous occlusion stage in order to minimize intracerebral hemorrhage or swelling. Schematic models of both fistulae and malformations are presented, together with reasons why particulate embolization is safer than glue embolization. The theory is advanced that dural fistulae, vein of Galen aneurysms, and AVM's are venous- rather than arterial-based lesions, which is consistent with the experience that permanent cure has been effected by venous side occlusion without excision in all three anomalies. It is speculated that there may be a developmental link between AVM and the venous malformation, the AVM being essentially a fistulized venous malformation.

Cavernous Sinus Dural Arteriovenous Fistula Associated With the Development of Sphenoidal Ridge Meningioma -Case Report-

“…8) Histological examination of resected sinuses with dural AVF demonstrated subintimal fibrous thickening and hypertrophic changes in the sinus wall with many dural vessels, which suggests the presence of previous sinus thrombosis. 11) Aberrant angiogenesis of the dural blood vessels could also lead to arteriovenous shunting.…”

Endovascular transvenous cure for ruptured brain arteriovenous malformations in complex cases with high Spetzler-Martin grades

“…Although in the past transvenous endovascular techniques were con- sidered risky, 5,13 the concept of venous side occlusion for permanent AVM cure has been around for 2 decades. 20 Advances in liquid embolic materials have allowed for development and evolution of this technique. We have been using the presented protocol during the past few years in select cases, 15 and, in our experience, when rules are respected there is no increased hemorrhagic risk over intraarterial techniques.…”

The putative role of the venous system in the genesis of vascular malformations

“…In such a hypotheti cal model, the proposed formation of the AVM parallels DAVF development: thrombosis and subsequent partial recanalization of the DVA rootlets may induce arterial izations of the DVA, creating the basis for a newly formed AVM. [45][46][47] Indeed, in a very interesting case report, Nuss baum and coworkers 49 documented development of mul tiple AVMs in the proximity of a DVA.…”