The variant with the absence of the superior petrosal venous and sinus: A potential pitfall of transvenous balloon-assisted embolisation of Borden type II transverse-sigmoid dural arteriovenous fistula

We describe a patient with Borden type II transverse-sigmoid dural arteriovenous fistula. On the venous phase of the left vertebral artery injection, there was no superior petrosal veins and sinus on the side of lesion. After transvenous balloon-assisted Onyx embolisation, the patient developed extensive venous infarction from venous occlusion. This report calls attention to a highly unusual variant in which the superior petrosal veins and sinus are absent, and the cerebellar veins will be drained by tributaries of the bridging veins in this circumstance. In such circumstances, occlusion of the bridging vein on the tentorial cerebellar surface may lead to complications during transverse-sigmoid dural arteriovenous fistula embolisation.