The Surgical Excision of Spinal Intradural Vascular Malformations

HE most important problem in the management of spinal intradural vascular malformations is to determine, in each case, whether the pathological vessels are crucial for the normal cord circulation. Depending upon this, excision or occlusion of the vessels will or will not cause ischemia. In this paper, our purpose is to discuss two such cases and certain related observations by others. Most studies of postmortem specimens have continued Wyburn-Mason's ~9 division of these lesions into two groups, after exclusion of the obviously neoplastic lesions such as hemangioblastomas, secondary vascular abnormalities with coarctation of the aorta or extraspinal venous occlusion, and telangiectasias. These two groups are the purely venous abnormality or angioma racemosum venosum, and the artery-to-vein fistula or arteriovenous angioma. Wyburn-Mason, in his comprehensive monograph of 1943, ~ found these two groups distinct, both pathologically and clinically. The venous lesions, the more common of the two, were primarily tortuous dilated vessels on the dorsum of the thoracolumbar cord with intimate involvement of the venous outflow. The clinical presentation was an intermittent and progressive deficit consistent with intramedullary venous stasis; and thrombosis and infarction in the lateral and posterior columns, which he observed microscopically. A monometric block and recurrent bleeding were infrequent. The arteriovenous lesions, in contrast, were more commonly in the dorsal and cervical segments with a larger vascular presentation on the lateral or anterior cord surface. Recurrent hemorrhage and monometric block, secondary to enlarged veins, were more frequent. In the subsequent gross and microscopic