Spinal arteriovenous fistula

Last revised by Francis Deng on 1 Aug 2019

Spinal arteriovenous fistulas (spinal AVFs) are characterized by abnormal communication and shunting of blood from an artery to a vein of the spine that bypasses the capillary bed.

Spinal arteriovenous fistulas represent approximately 70% of all spinal vascular malformations 1,2.

Arteriovenous fistulas cause spinal venous congestion, the symptoms of which are nonspecific and include 3,4:

  • motor symptoms such as gait disturbance and reduced power
  • sensory symptoms such as paresthesia
  • radicular pain

The symptoms can be intermittent, progressive and ascending and relate to cord edema as opposed to the exact location of the arteriovenous fistula 4.

Late symptoms include 5:

  • bowel and bladder incontinence
  • erectile dysfunction

The pathogenesis of arteriovenous fistulas is unknown and hypothesized to be an acquired condition 6.

Arteriovenous fistulas are generally classified by size and angioarchitecture, and are distinct from spinal arteriovenous malformations (spinal AVMs), which collectively are known as spinal vascular malformations 7:

  • type 1: dural arteriovenous fistula
  • type 2: intramedullary glomus arteriovenous malformation
  • type 3: intramedullary juvenile arteriovenous malformation
  • type 4: perimedullary arteriovenous fistula
    • subtype 4a: single feeder, small
    • subtype 4b: multiple feeders, medium
    • subtype 4c: multiple feeders, giant
  • type 5: extradural arteriovenous fistula
    • subtype 5a: with intradural venous drainage
    • subtype 5b: without intradural venous drainage

Classic findings include 6:

  • tortuous and enlarged vessel flow voids around the spinal cord
  • spinal cord edema that is usually centromedullary and multisegmental

A low T2 rim at the periphery of the edema is thought to be secondary to deoxygenated blood product 8.

DSA is the gold standard modality for imaging of arteriovenous fistulas. It allows confirmation of diagnosis with precise identification and mapping of the arterial feeding and venous drainage of the fistulas.

Treatment aims to occlude or obliterate the shunting zone from both the arterial and venous part of the arteriovenous fistula. Microsurgical and/or endovascular strategies have a role and can be indicated by the classification of the arteriovenous fistula 7:

  • type 1: (see: spinal dural arteriovenous fistula)
  • subtype 4a: microsurgery
  • subtype 4c: endovascular embolization
  • subtype 5a: microsurgery and endovascular embolization
  • subtype 5b: endovascular

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.