Spinal epidural arteriovenous fistulas

Abstract

Spinal epidural arteriovenous fistulas (SEDAVFs) are rare complex lesions often presenting with protean clinical manifestations secondary to compressive symptoms or congestive myelopathy. The imaging manifestations of SEDAVFs on MR angiography/MRI include high T2 signal in the spinal cord, vascular engorgement of the epidural space, and prominent intradural vascular flow voids. Given the complexity of these lesions, they are best characterized anatomically on catheter angiography where careful inspection of arterial feeders and venous drainage patterns can be performed. The imaging hallmark of an SEDAVF on angiography is the presence of a dilated epidural venous pouch through which spinal and paraspinal veins are secondarily opacified. In the lower thoracic and lumbar spine, SEDAVFs are usually located in the ventral epidural space and fed mainly by the anteriorly coursing epidural arteries. In the cervical and upper thoracic spine, SEDAVFs and their feeding arteries are more typically located laterally in the spinal canal. Current treatment options include transarterial or transvenous endovascular embolization with liquid embolic agents or coils, and surgical resection/disconnection of the fistula. Further research is needed to better characterize how and why these lesions form and to identify the best treatment modalities.