Filum Terminale Arteriovenous Fistula with Additional Arterial Supply by the Posterior Spinal Artery: A Report of Two Cases

Filum terminale arteriovenous fistulas (FTAVFs) are rare and usually supplied by the artery of the filum terminale, distal termination of the anterior spinal artery (ASA). These fistulas may also supply from the lateral sacral artery (LSA) arising from the internal iliac artery and/or middle sacral artery. Additional supply by the posterior spinal artery (PSA) has never been mentioned before. The authors describe two middle-aged men harboring FTAVFs manifested with progressive myelopathy and bowel/bladder dysfunction. The first fistula was supplied by the ASA with additional supply by the dilated PSA connecting with the ASA. Another fistula was supplied by the LSA and the PSA communicating with the ASA. The first case was successfully treated by endovascular treatment with N-butyl cyanoacrylate through the enlarged PSA, whereas the second case was surgically treated by direct obliteration of the fistula. Both patients had good neurological outcome.