Dural arteriovenous fistula and progressive conus medullaris syndrome as complications of lumbar discectomy. Case report.

A case of a dural arteriovenous fistula (DAVF) that developed at the site of nerve root sleeve damage as a result of lumbar disc extrusion is reported. A 60-year-old man who had undergone lumbar discectomy 3 years previously for severe left-sided sciatica and L5-S1 disc herniation presented with progressive gait disturbance. After the initial surgery, the symptoms resolved. Fourteen months after the operation, however, he started to experience dysesthesias in both legs and progressive gait and urinary disturbances. Physical examination revealed a weakness of the anterior tibialis and the gastrocnemius muscles, as well as decreased contractility of the anal sphincter and marked sacral hypesthesia. Magnetic resonance (MR) imaging revealed swelling and a T2 signal elongation in the conus medullaris; angiography demonstrated arteriovenous dural shunting between the left lateral sacral artery and the left S-1 radicular vein at the site of the previous operation. Surgery was conducted to excise the DAVF on the S-1 nerve root sleeve and an arterialized intradural vein on the root. The procedure resulted in resolution of the symptoms and disappearance of the abnormal angiographically and MR imaging-documented anomalies. This is the first report of a DAVF in which progressive conus myelopathy developed after a lumbar discectomy.