Treatment and outcome of spinal dural arteriovenous fistulas.

Spinal dural arteriovenous fistula (dAVFs) are rare and often misdiagnosed entities. The choice between surgical treatment and embolization remains a matter of debate. We report on the cases of 18 patients (16 men, 2 women) with dAVF, who were treated surgically over an 11-year period. Patient age ranged from 32 to 84 years (mean 60 years). Six patients underwent embolization preoperatively. In three cases, angiography examinations failed to show feeding arteries on first examination at neuroradiological centers. Feeding arteries were at a different level than the fistula point in seven patients, two of them presenting with new anastomoses after embolization. Location of the fistula was midthoracic to lumbar. Seven patients were variously misdiagnosed with tumor, polyneuropathy, Guillain-Barré syndrome, syringomyelia, and knee disease. Clinical history was characterized by slowly progressive and fluctuating deterioration. Initial symptoms were mainly sensory loss and motor weakness, lasting for between 4 and 45 months before diagnosis (mean 15 months). Recurrent fistula after operation was found in one patient. In another patient, control angiography revealed a fistula at another level, and in a third, a fistula on the contralateral side. All three patients underwent reoperation. Temporary clinical deterioration was found in four patients, seven remained unchanged, and seven improved postoperatively. An attempt at embolization should be made following diagnostic angiography. Otherwise, surgery is our recommended treatment for spinal dural fistulas, as it has a lower failure rate. Because of the progressive natural course with severe deficits, we favor an early definitive treatment.