Dural arteriovenous shunt development in patients with vein of galen malformation.

Dural arteriovenous fistulas (DAVF) associated with our series of patients with vein of Galen malformations (VOGM) are analyzed and discussed. We retrospectively analyzed 87 consecutive cases of VOGM treated between May 2002 and December 2011 and identified 26 patients with DAVF. We gathered information from the clinical case records, angiographic images, MRI on presentation and during follow-up. The findings were analyzed to aid discussion. Among 87 patients treated by multi-stage endovascular embolization, age range from newborn to 19 years, 26(30%) had DAVF. In seven patients (8%), DAVF were found on initial angiogram and were all into the VOGM. Nineteen (21%) DAVF found on follow-up angiograms were all into the VOGM and distant locations. Sprouting and non-sprouting angiogenesis resulted in the formation of a network of vessels around partially thrombosed VOGM, recruiting blood from the surrounding dura mater resulting in a secondary network on the dura mater supplied by the blood vessels of dura mater in the region or from its natural collaterals. Embolization targeting DAVFs was done in 13 (52%) with complete cure in eight (32%) and recurrence in five (20%). Among 12 non-embolized patients (48%), eight (32%) had spontaneous regression with continued treatment of VOGM. In others, the DAVF either remained stable or progressed. DAVF associated with VOGM represent the dural response to angiogenic stimuli. They are observed to regress spontaneously or mature while continuing to treat the primary feeders of VOGM. It is important to include the external carotid system during angiograms. Persistent DAVF with residual VOGM that do not have access though the pial vessels are used as a conduit to treat the dural shunt and to achieve obliteration of residual VOGM at later stages of treatment.