A spinal arteriovenous malformation is an abnormal collection or tangle of blood vessels in or around the spinal cord. Normally, blood supplies the spinal cord with oxygen through arteries that branch into capillaries. Then, veins move this oxygen depleted blood back to the heart and lungs. The capillaries usually separate arteries from veins. In spinal arteriovenous malformations capillaries are absent and the blood flow is altered. The blood goes directly from the arteries to the veins and cells in the spinal tissues deteriorate or die.
Often people with a spinal arteriovenous malformation experience no or few symptoms. When symptoms occur, they vary on the severity and location of the malformation. Eighty-five percent of spinal arteriovenous malformations occur between ages 20 and 60 and involve progressive symptoms over months to years, especially:
- Lower back pain
- Problems with walking
- Problems with climbing stairs
- Lower extremity weakness
- Sensory loss
- Difficulty Urinating
- Urinary or fecal incontinence
Ten percent to twenty involve sudden onset of symptoms as a result of hemorrhage.
The specific cause is unknown.
Risk factors are also unknown.