Dural Arteriovenous Fistula of the Spinal Cord: An Uncommon Cause of Myelopathy

Dural arteriovenous fistula is an uncommon cause of myelopathy. The nidus of the malformation is on or within the dura and results in a mass of serpentine vessels on the dorsal surface of the spinal cord, usually at low thoracic or lumbar levels. Onset is usually between ages 40 and 70 years. Male to female ratio is 4:1. Symptoms include pain, progressive proximal weakness of lower limbs, saddle area numbness, claudication, and difficulty with urination. Course may be fluctuating or slowly progressive. Signs include upper and lower motor neuron abnormalities and nondermatomal sensory loss. Spinal bruit is rare. Magnetic resonance imaging may show an enlarged cord or abnormalities on its dorsal surface. Myelography (patient prone and supine) is the procedure of choice. Motor neuron disease, disc disease, spinal cord tumor, and multiple sclerosis are differential considerations. Untreated patients have a poor prognosis. Exicision of the nidus, ligation of the draining vein, and endovascular embolization may be helpful, even in patients with severe deficits.