A vascular malformation is an abnormal collection or tangle of blood vessels on, in, or near the spinal cord. Two of the most common types are arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs).
AVMs are caused when oxygen-rich blood, which normally enters your spinal cord through arteries and blood vessels, bypasses the blood vessels, or capillaries, and passes directly into the veins. The spinal cord doesn’t receive enough oxygen and causes spinal tissues to deteriorate or die. Sometimes the spinal AVM can rupture, causing bleeding in the spinal cord. As AVMs grow, they may put pressure on the spinal cord.
AVFs account for 70 percent of all spinal vascular malformations and usually appear in the thoracic (mid back) spine near the nerve root. They are caused by an abnormal connection between arteries and the tough covering over the spinal cord and a draining vein. AVFs create congestion in the veins and hypertension, resulting in decreased blood flow through the organs, oxygen depletion, and swelling of the spinal cord.
At UPMC we treat several treatments for vascular malformations on the spine. Depending on the location of the malformation, surgeons may recommend resection surgery, endovascular embolization, or a combination of both. Surgery involves the removal of the malformation from the surrounding tissue. In endovascular embolization, the surgeon threads a long thin tube into an artery in the leg through the blood vessels to the spinal cord using x-ray imaging. A substance is injected to block the artery and reduce blood flow to the malformation.
To diagnose spinal vascular malformations, the doctor will conduct a full physical examination and medical history. Patients with the more common AVF typically have different symptoms than those with AVMs. AVFs are more common in men and usually occur between the ages of 50 and 80. Patients with AVMs are typically younger than 30 years old.
Symptoms of spinal AVMs may include:
Symptoms of spinal AVFs may include:
Angiography is used to pinpoint the location and characteristics of the feeding arteries and draining veins. CT scan can show the feeding arteries and draining veins in greater detail. An MRI may provide information about the exact location of the malformation, which helps in determining treatment.
At UPMC we treat vascular malformations with endovascular embolization, surgical removal (resection), or a combination of both, depending on the size and location of the abnormal blood vessels. Endovascular embolization is a technique that reduces blood flow to the area. The neurosurgeon will inject a glue-like substance to block the blood vessels and reduce blood flow into the malformation.
Embolization may be done prior to microsurgical resection. Once the vascular malformation has been removed from circulation, surgical removal becomes significantly easier.