Background and importance: Galenic dural arteriovenous fistulas (DAVFs) are a subtype of the rare falcotentorial DAVFs with a high risk of hemorrhage and an aggressive clinical course. Microsurgical treatment is often necessary because endovascular obliteration will rarely completely obliterate the DAVF.
Clinical presentation: We present a unique case of a complex, ruptured galenic DAVF in which the key point of the fistula was formed by a large venous aneurysm of the vein of Galen. A session of embolization of the falcotentorial feeding vessels followed by additional surgical transsection of the remaining tentorial arterial feeders failed to exclude the galenic DAVF. Direct clipping of the venous aneurysm through a unilateral occipital craniotomy for a posterior interhemispheric transtentorial approach resulted in an ongoing radiological complete obliteration in this patient, who made an uneventful complete recovery after 2 subarachnoid hemorrhages, which he suffered before this definitive treatment.
Conclusion: Direct interruption of the fistula key point by clipping of the venous aneurysm, rather than interruption of the feeding vessels, was mandatory for complete exclusion of this complex galenic DAVF.