Spinal dural arteriovenous malformations with perimedullary drainage. Indications and results of surgery in 30 cases

70 patients were treated for spinal dural arteriovenous fistula in the same centre, during a period of 10 years. Conus medullaris and cauda equina syndromes were observed in all patients as the clinical stereotyped presentation. Diagnosis was based on myelography in the first instance and then on angiography. 40 patients were treated by intravascular neuroradiological embolization, whereas the other 30 were operated on. Surgery was proposed because embolization was contraindicated (7 cases of hazardous catheterisation) of inefficient (23 cases = 38%). The results of the operative series are presented, and compared with those of embolization. Improvement was observed in 50% of the 20 patients with follow up, but a complete recovery to an asymptomatic state was never obtained. For the other patients (47%) complete stabilization of the disease could be obtained, whereas in one of the patients (3%), who was operated upon because of failure of embolization, surgery was also completely ineffectual. The long-term results of patients treated surgically are comparable with those patients efficiently embolized. 5 patients of the operative series were submitted to MRI before and after surgery: the results and the place of MRI are discussed.