title: Sacral intradural arteriovenous fistula treated indirectly by transection of the filum terminale: technical case report.
abstract: BACKGROUND
  Type A intradural arteriovenous fistulae of the sacral filum terminale are rare lesions fed primarily by the distal anterior spinal artery. The artery is frequently too narrow or tortuous for endovascular obliteration, and direct surgical resection of the fistula requires an invasive sacrectomy. We present a less invasive indirect surgical approach through an L4 laminectomy and transection of the filum terminale rostral to the fistula.
  
  
  METHODS
  A 62-year-old man presented with a 6-month history of progressive bilateral lower extremity paresthesias and weakness and associated incontinence and impotence. Spinal magnetic resonance imaging demonstrated perimedullary flow voids. Selective spinal angiography revealed a fistula at S2-3 between the distal anterior spinal artery and an early draining vein returning cranially along the filum terminale, diagnostic of an intradural arteriovenous fistula. An L4 laminectomy and transection of the filum terminale rostral to the lesion were performed to disrupt the medullary arterial supply to the intradural fistula and outflow to the medullary venous plexus of the spinal cord. At 10-month clinical follow, up the patient had regained bowel and bladder continence, was able to ambulate with a cane, and reported subjective improvement of lower extremity paresthesias. Selective spinal angiography at 1 year demonstrated no residual arteriovenous shunt.
  
  
  CONCLUSIONS
  Pathological venous hypertension of a type A intradural arteriovenous fistula of the sacral filum terminale can be treated by transection of the filum terminale at L4. This avoids posterior partial sacrectomy required for direct resection; however, subsequent clinical follow-up is necessary to monitor for reconstitution.
authors.affiliation: School of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Witiw
authors.forename: Aria
authors.initials: A
authors.lastname: Fallah
authors.forename: Ivan
authors.initials: I
authors.lastname: Radovanovic
authors.forename: M Christopher
authors.initials: MC
authors.lastname: Wallace
mesh_terms: D015901:Angiography, Digital Subtraction; D001164:Arteriovenous Fistula / Q000473:pathology / Q000601:surgery; D002420:Cauda Equina / Q000601:surgery*; D004487:Edema / Q000209:etiology; D006801:Humans; D007796:Laminectomy; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology; D019635:Neurosurgical Procedures / Q000379:methods*; D010292:Paresthesia / Q000209:etiology; D012039:Regional Blood Flow; D013116:Spinal Cord / Q000098:blood supply / Q000473:pathology; D013118:Spinal Cord Diseases / Q000473:pathology / Q000601:surgery*