About Spinal Arteriovenous Malformations
A spinal arteriovenous malformation (AVM) is an abnormal collection of blood vessels that makes direct connection between the arteries and veins in or around your spinal cord. Due to this condition, the capillaries that typically connect veins and arteries are missing, causing extra pressure and a lack of nutrient exchange to the spinal cord tissue. This is essentially a plumbing problem where the veins that are supposed to drain blood away from your nerves experience abnormally high pressure. This can lead to a backing up of fluid in your spinal cord, like your sink or toilet backing up from a blockage in the pipes. In the spinal cord, this can produce swelling, leading to nerve dysfunction or damage.
Sometimes the high pressure causes a vessel to rupture, like a pipe bursting. This can lead to sudden onset of neurological symptoms such as weakness and numbness. Once diagnosed, spinal AVMs are generally treated with surgery and endovascular treatments.
There is no known cause of spinal AVMs, or risk factors that may lead to developing the condition. Some cases of spinal AVM are present at birth, but many cases develop later in life.
Common Symptoms of Spinal Arteriovenous Malformations
The majority of symptoms produced by spinal AVMs will cause neurological issues that will gradually worsen. Such symptoms include pain, sensory loss, and weakness. A small percentage of spinal AVM cases will cause sudden severe symptoms, such as weakness, numbness, difficulty controlling bowel/bladder, or paralysis. These sudden symptoms may be due to a bursting of the malformation.
Diagnosis of Spinal Arteriovenous Malformations
First, the patient’s symptoms and medical history are reviewed and a physical exam is completed. Advanced imaging is required, such as an MRI scan to locate and define the extent of the lesion.
Spinal angiography (an image that demonstrates blood flow on an X-ray through injection of a tracer) is also necessary to accurately identify the architecture of the malformation, which blood vessels are involved, and how blood flows through the malformation.
Treatment Options for Spinal Arteriovenous Malformations
Often a procedure called endovascular embolization is used to treat spinal arteriovenous malformations. This process involves passing a small tube into the vessels feeding into the AVM. The tube then releases a glue like material to seal off sections or all of the malformation. This procedure may not obliterate the lesion, therefore surgery is often considered in conjunction with endovascular treatments. If too extensive, radiation may be considered to treat a spinal AVM.