Perimedullary Arteriovenous Fistula of the Filum Terminale: Case Report

OBJECTIVE: Although a dural or intramedullary arteriovenous fistula involving the conus medullaris and fed by the lateral sacral artery has been reported, a case of perimedullary fistula arising from an artery in the filum terminale has not been described in the literature. The authors report the first case of perimedullary arteriovenous fistula located in the filum terminale. CLINICAL PRESENTATION: A 61-year-old man presented with a 10-year history of leg pain. Thoracolumbar magnetic resonance imaging scans revealed multiple perimedullary signal voids from T10 to L3. Angiography showed engorged perimedullary veins and a fistula fed by the anterior spinal artery from the right ninth segmental artery and by 2 branches of the left lateral sacral artery. The anterior spinal artery was also regarded as the artery of the filum terminale. INTERVENTION: Transarterial embolization was performed to occlude the feeders from the left lateral sacral artery, and an L5 total laminectomy was subsequently performed to obliterate residual fistulous material from the artery of the filum terminale. The thickened, yellowish filum, surrounded by tortuous, engorged veins, was coagulated and resected. Postoperatively, the patient's symptoms gradually resolved and were not aggravated during long periods of walking. CONCLUSION: It must be noted that a fistula can be located in the filum terminale and can be successfully treated using multidisciplinary approaches.