A 64-year-old man was admitted to our institute due to a 3-month history of progressive paraparesis. Three years earlier, he experienced low back pain radiating to both legs, predominantly affecting the right side. He also had numbness in lower extremities, affecting the left more than right side. He was treated by medicine and physiotherapy at the local hospital. One month before the hospitalization, he was unable to walk without assistant. In addition, urine retention and constipation were noticed 2 weeks before admission. His back was injured by falling from a tree at a height of 3 m 4 years ago. The neurological examination revealed the evidence of spastic paraparesis (muscle strength 2/5), the lack of pinprick sensation below T10 level, hyperreflexia, and presence of Babinski sign in the lower extremities. Magnetic resonance imaging (MRI) of the thoracolumbar spine showed hyperintense T1 signal, hypointense T2 signal with blooming on gradient-echo (GRE) T2*-weighted image in the abnormal flow void running from sacral level to the conus medullaris, probably representing subacute thrombosis. There were abnormal hyperintense T2 signal representing spinal cord congestion extending from the conus medullaris to the level of T3 and subtle perimedullary flow voids along the posterior surface of cord. After gadolinium contrast, diffuse enhancement of lower spinal cord and cauda equina nerve roots was observed []. Further findings were compression fracture of L2 vertebra, Grade I degenerative retrolisthesis at the level of L2-3, and L3-4, and thickened ligamentum flavum with hypertrophic facet joints at the level of L2-3, L3-4, and L4-5, causing spinal stenosis at L2-3, L3-4, and L4-5. Contrast-enhanced magnetic resonance angiography (MRA) of the thoracolumbar spine demonstrates tortuous and enlarged intradural vessels at the midline location extending from the level of lower lumbar to thoracic level []. Spinal angiography demonstrated an AVF at the level of S2, which is supplied by the branches from bilateral lateral sacral arteries (LSA) with cranial drainage into the dilated vein of the FT. The middle sacral artery (MSA) anastomosing with the distal branch of left LSA was identified. The ASA arose from the left L3 segmental artery without supplying to the fistula. Maximum intensity projection (MIP) reformatted image of angiographic computerized tomography (CT) and three-dimensional reconstructed image clearly revealed the fistulous point at the level of S2. The fistula fed by two branches from the left LSA. One upper branch ran through the fourth sacral foramen. Another lower branch traveled through the sacral hiatus and then joins the straight artery along the filum terminale externum (FTE). The fistula was supplied by the right LSA through the right first sacral foramen [ and ]. The patient underwent surgical treatment. To avoid invasive posterior sacrectomy, we decided to obliterate the dilated intradural draining vein rostral to the fistula. Laminotomy was performed at the level of L5. After durotomy, the arachnoid membrane was found to be thickened and opaque. The arachnoid was gently separated. The roots of the cauda equina were mattered together with adhesions. The FT was adhered within the clumping of the cauda equina. Lysis of adhesions between the nerve roots was performed. After lysis of adhesions, the engorged vein run parallel with the FT was identified. Part of the dilated vein was resected along with the FT []. Histopathological examination disclosed dilated vessel and thickened vascular wall, surrounded by fibrofatty tissue. Attached small nerve fibers are noted. These findings were consistent with dilated vein of the FT embedded in fatty FT []. His postoperative course was uneventful. Follow-up spinal angiography obtained 1 week after the operation confirmed complete obliteration of an arteriovenous fistula []. He was discharged home 2 weeks later and was sent to the local hospital for physical rehabilitation. MRI of the thoracolumbar spine obtained 3 months after the surgery showed hyperintense T1 and T2 signal with blooming on GRE image along the flow void running from the level of L5 to L2, probably representing complete thrombosis of the vein of the FT above the clipping point. There was only minimal persistent central cord enhancement []. Moreover, the resolution of spinal cord congestion and disappearance of perimedullary flow voids were observed. Contrast-enhanced MRA of the thoracolumbar spine confirmed no recurrent of the fistula []. At the 4-month follow-up, the patient was able to walk independently without bowel/bladder dysfunction, although he still experienced numbness in his left leg.