Intracranial Dural Fistulas with Exclusive Perimedullary Drainage: The Need for Complete Cerebral Angiography for Diagnosis and Treatment Planning

SUMMARY: Three patients are presented with slowly progressive tetraparesis caused by an intracra-nial dural arteriovenous fistula with exclusive perimedullary venous drainage. MR imaging showed a swollen cervicothoracic cord with central myelopathy and dilated perimedullary veins. Bilateral verte-bral angiography initially failed to demonstrate the fistulas, and diagnosis was established with external carotid angiography. All 3 patients were successfully treated with glue embolization, 1 after failed surgical exploration. Angiographic cure of the fistula resulted in clinical cure in 1 patient and stabilization in 2 patients. Intracranial dural fistula (DAVF) consists of a meshwork ofarteriovenous shunts and can be localized anywhere in the dura surrounding the brain. DAVFs are acquired lesions, probably as a result of venous thrombosis. Drainage of the fistula can be into a dural sinus, with or without reflux into cortical veins, or directly into cortical veins. Drainage into cortical veins is often associated with intracranial hemorrhage or seizures. The DAVF consists of multiple dural branches of various dural arteries converging at the site of the fistula to join a single draining vein. Surgical or endovascular repair is aimed at closure of the draining vein. If only feeding arteries are oc-cluded and not the draining vein, collateral vessels usually de-velop and the fistula reopens.1-3 Rarely, intracranial dural fistulas drain exclusively into veins around the brain stem and further downward into peri-medullary veins. This retrograde drainage causes congestion in the perimedullary venous system, which, in turn, leads to decreased tissue perfusion with edema and progressive loss of cord function.4-6 In this article, we report 3 patients who presented with progressive cervical cord dysfunction caused by an intracra-nial DAVF with perimedullary venous drainage who were treated with endovascular occlusion of the draining vein with glue