Spinal arteriovenous malformation (AVM) is a tangle of blood vessels on, in or near the spinal cord. Without treatment, this rare condition can permanently damage the spinal cord.

Oxygen-rich blood usually enters the spinal cord through arteries, which branch into smaller blood vessels (capillaries). The spinal cord uses the oxygen from the blood in the capillaries. The blood then passes into veins that drain blood away from the spinal cord to the heart and lungs.

In a spinal AVM, the blood passes directly from the arteries to the veins and goes around the capillaries.

This change in blood flow means that the surrounding cells don't get the oxygen they need. The cells in the spinal tissue can weaken or die.

The tangled arteries and veins in a spinal AVM can also burst and cause bleeding in the spinal cord (hemorrhage). Sometimes, the AVM may grow over time as blood flow increases and presses on the spinal cord, leading to disability or other problems.

You might not know you have a spinal AVM unless you begin experiencing symptoms. The condition can be treated with surgery to stop or possibly undo some of the spinal damage.


Symptoms of spinal AVM can differ from person to person. Symptoms depend on where the AVM is found and how severe it is. Some people may not notice symptoms for many years, if at all. Others may experience symptoms that are debilitating or life-threatening.

Symptoms usually develop when people are in their 20s, although almost 20% of people diagnosed with spinal AVM are under the age of 16.

Symptoms may start suddenly or slowly. Symptoms usually include:

  • Problems with walking or climbing stairs
  • Numbness, tingling or sudden pain in the legs
  • Weakness on one or both sides of the body

As the condition gets worse, you may have more symptoms including:

  • Sudden, severe back pain
  • Lack of feeling in the legs
  • Difficulty urinating or having bowel movements
  • Headache
  • Stiff neck
  • Sensitivity to light

When to see a doctor

Make an appointment with your health care provider if you experience symptoms of spinal arteriovenous malformation.


The specific cause isn't known. Most spinal AVMs are present at birth (congenital), but others may happen later in life.

Risk factors

There are no known risk factors for spinal arteriovenous malformation. The condition occurs equally in men and women.


Without treatment, spinal arteriovenous malformation can cause disability that gets worse over time. This is from damage to the spinal cord and surrounding tissues. These problems may include:

  • Difficulty with moving (motor deficits)
  • Pain, tingling and numbness (sensory deficits)
  • Spinal column deformity
  • Bulging blood vessel (aneurysm)
  • High blood pressure in the veins (venous hypertension), which can cause fluid accumulation (edema) and tissue death due to lack of oxygen (spinal cord infarction)
  • Hemorrhage, which can speed up spinal cord damage

Spinal arteriovenous malformation (AVM) care at Mayo Clinic

Aug. 03, 2022
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