Spinal cord arteriovenous malformations with significant intramedullary components.

Few neurosurgeons have stressed the occurrence, manifestations, and resectability of intramedullary spinal arteriovenous malformations (AVM's). In six of 17 patients in the authors' series of operable spinal AVM's, the lesions had major intramedullary components. Three of these six patients presented with subarachnoid hemorrhage, and all had catastrophic neurological deficits which gradually improved. The hemorrhages appeared to originate from large venous varices lying adjacent to the intramedullary portion of the AVM. The mechanism explaining the sudden neurological deficit in the other three patients was presumed to be thrombosis within the venous varices associated with their AVM's. The reliability of the various radiographic procedures in identifying the intramedullary components of these AVM's is discussed. These malformations may be removed totally with a high degree of safety using microsurgical techniques. The postoperative course in this series of patients was gratifying in terms of improvement of neurological deficits. Postoperative angiography was not performed on all of these patients. However, the follow-up period averaged 5 years.