Spine Arteriovenous Fistula
A spine arteriovenous fistula is an abnormal connection between an artery and a vein in the spine. Normally, arteries carry blood away from the heart to different parts of the body, and you can feel a pulse in an artery because they have high pressure in them. Larger arteries branch into smaller and smaller branches until they get down to tiny branches called capillaries; that is where the oxygen and nutrients are exchanged with the tissues in your body. The blood is then returned from the tissues in veins. The veins have very low pressure, and you cannot feel a pulse in a vein.
Signs and Symptoms
Spinal arteriovenous fistulas start off causing no symptoms, but as the fistula grows, symptoms start to develop. Common symptoms include:
- Leg weakness, tingling, numbness or burning
- Pain in the back or legs
- Changes in bowel function
- Trouble urinating
- Urinary or fecal incontinence
Fistulas can occur after trauma, but many times they happen spontaneously for no known reason.
Many other conditions can cause the same symptoms, so it is important to check with your doctor for an accurate diagnosis. Only a doctor experienced in recognizing the exact combination of symptoms that indicate a spine arteriovenous fistula can make a firm diagnosis.
Sometimes a fistula will be seen on an MRI or a CT scan, but the gold standard to find a fistula is by using angiography.
If you have a fistula, there are a few different ways it can be treated:
- Observation This is recommended when there does not appear to be high pressure in the veins and the patient has minor or no symptoms.
- Embolization This is a general term for closing off, or occluding a vessel. In most cases, the vessel being closed is abnormal, though in some it may be normal but not absolutely necessary for normal function. It is generally done in cases of poorly controlled bleeding, or to reduce bleeding prior to a surgical procedure, and occasionally to cure a lesion of the blood vessels. This is often needed for conditions such as tumors of the head, neck or spine that contain a lot of blood vessels, uncontrolled nosebleeds or abnormal connections between arteries and veins. Embolization uses a catheter placed in the arteries or veins which is “snaked” all the way up to where the fistula is located. A special glue is injected to shut down the fistula from the inside. The advantage is you do not have to have surgery, but there are some fistulas that embolization cannot cure.
- Fistula disconnection surgery This is done using anesthesia with the patient completely asleep. An incision is made, depending on the location of the fistula. A window is made in the bone, and the same bone is put back at the end. Using a microscope, the fistula is located. Once the fistula is located, metal clips are placed on it to shut it down. If all of the abnormal connections are shut down, the fistula is cured at that time. Usually, an angiogram is done during the surgery to make sure that the fistula is completely gone.