Intradural perimedullary arteriovenous fistulas (type IV spinal cord arteriovenous malformations).

Intradural perimedullary arteriovenous fistulas (Type IV spinal cord arteriovenous malformations (AVM's)) are rarely reported in the literature and occasionally are classified together with Type II AVM's as intradural spinal cord AVM's. The authors report eight cases of Type IV spinal cord AVM's managed over a 2-year period. Seven of these AVM's were surgically obliterated, with intraoperative angiography being used as an adjunct; one other patient was managed using endovascular therapy. One of these lesions was definitely and another possibly the result of trauma; a malformation in a newborn infant was clearly congenital. The authors believe that the pathophysiological mechanisms and anatomical features of these lesions represent a unique spinal vascular anomaly that must be recognized angiographically to plan appropriate therapy.