A spinal arteriovenous malformation (AVM) is an abnormal tangle of blood vessels on, in or near the spinal cord.
Oxygen-rich blood normally enters your spinal cord through arteries, which branch into smaller arterioles and smaller blood vessels (capillaries). Your spinal cord uses oxygen from the blood in your capillaries, and this oxygen-depleted blood then passes into veins that drain blood from your spinal cord to your heart and lungs. In a spinal AVM, your blood passes directly from your arteries to your veins, bypassing capillaries. This disruption in blood flow causes cells in your spinal tissues to deteriorate or die. The arteries and veins in a spinal AVM can rupture, which results in bleeding in the spinal cord (hemorrhage). Sometimes, the AVM enlarges and compresses the spinal cord. AVMs often are detected on an imaging study performed for symptoms unrelated to the AVM.
Dural arteriovenous fistulas, a type of arteriovenous malformation, are abnormal connections between arteries and the tough covering over the spinal cord (dura) and a draining vein.
Nov. 20, 2012