Surgical treatment of spinal extradural arteriovenous fistula with parenchymal drainage: report on 5 cases.

Abstract

Spinal extradural arteriovenous fistula (SEDAVF) with parenchymal drainage (type A) is a rare clinical entity that causes venous congestive myelopathy. Treatment includes endovascular and open microsurgical interventions. We reviewed the clinical records of patients treated for a type A SEDAVF to evaluate the feasibility of our treatment strategy. Between 2004 and 2010, 5 patients with a type A SEDAVF were treated at our institutes (4 men and 1 woman; mean age, 60 years). We performed endovascular transvenous embolization (TVE) when lesions were accessible transvenously; otherwise, microsurgical perimedullary drainer occlusion was performed. Follow-up ranged from 23 to 94 months (mean, 45.8 months). One patient was treated with TVE, and the remaining 4 were treated with microsurgical drainer occlusion. After a simple intradural drainer occlusion, an epidural venous lake was completely thrombosed in 2 patients. In 1 patient, postoperative angiography revealed that a part of the epidural component had persisted; however, the patient has been asymptomatic. In the remaining case with multiple intradural draining veins, sole drainer occlusion was not sufficient. A second surgery was required to meticulously coagulate the venous lake. As a consequence, parenchymal drainers disappeared. Overall, all patients stabilized or improved neurologically and experienced no recurrence. To treat a type A SEDAVF, either TVE or microsurgical intradural drainer occlusion can be used for satisfactory long-term results with minimal surgical risks. For a case with multiple intradural draining veins, detachment of the venous lake should be considered.