Spinal arteriovenous malformation (AVM) is a rare, abnormal tangle of blood vessels on, in or near the spinal cord. Without treatment, spinal AVM can permanently damage your spinal cord.
Oxygen-rich blood normally enters your spinal cord through arteries, which branch into smaller blood vessels (capillaries). Your spinal cord uses the oxygen from the blood in your capillaries. The oxygen-depleted blood then passes into veins that drain blood away from your spinal cord to your heart and lungs.
In a spinal AVM, the blood passes directly from your arteries to your veins, bypassing the capillaries.
This disruption in blood flow deprives the surrounding cells of vital oxygen and causes cells in your spinal tissues to deteriorate or die.
The arteries and veins in a spinal AVM can also rupture and cause bleeding in the spinal cord (hemorrhage). Sometimes, the AVM may enlarge over time as blood flow increases and compress the spinal cord, leading to disability or other complications.
Spinal AVM can go undiagnosed unless you begin experiencing signs and symptoms. The condition can be treated with surgery to halt or possibly reverse some of the spinal damage.
Spinal AVM care at Mayo Clinic
Symptoms of spinal AVM vary greatly from person to person depending on the severity and location of the AVM. Some people may not develop noticeable 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 percent of people diagnosed with spinal AVM are under the age of 16.
The emergence of symptoms may be sudden or gradual. Symptoms typically include:
- Problems with walking or climbing stairs
- Numbness, tingling or sudden pain in your legs
- Weakness on one or both sides of your body
As the condition progresses, additional symptoms may include:
- Sudden, severe back pain
- Lack of feeling in the legs
- Difficulty urinating or moving your bowels
- Stiff neck
- Sensitivity to light
When to see a doctor
Make an appointment with your doctor if you experience signs and symptoms of spinal arteriovenous malformation.
The specific cause isn't known. Most spinal AVMs are present at birth (congenital), but others may occur later in life.
There are no known risk factors for spinal arteriovenous malformation. The condition occurs equally in men and women.
Untreated, spinal arteriovenous malformation can lead to progressive disability by damaging the spinal cord and surrounding tissues. Specific complications may include:
- Problems 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 accelerate spinal cord damage