What is a spinal angiogram?
A diagnostic spinal angiogram is a medical procedure that offers an extremely precise evaluation of the blood vessels surrounding the spinal cord. During a spinal angiogram, highly specialized doctors (called neuro-angiographers) are able to observe arteries and veins by using modern sophisticated imaging equipment. In order to take pictures of the blood vessels, a contrast medium (or "dye") is gently injected through a small, soft, and flexible tube called a catheter. This catheter is inserted in the groin and carefully advanced into the targeted blood vessel under the guidance of low dose x-rays (Figure 1). As there is no sensation associated with the advancement of the catheter inside the blood vessels, diagnostic spinal angiography is generally performed under light sedation as an outpatient procedure (meaning that patients come for the procedure and go home the same day). In our practice, the majority of patient do not need general anesthesia. When they do, it is generally because of associated medical conditions. In that case, the angiogram is still most often performed as an outpatient procedure.
What conditions can be diagnosed with a spinal angiogram?
Spinal angiography helps diagnosing medical conditions that involve the arteries and veins of the spinal cord. This typically includes spinal cord vascular malformations, such as dural arteriovenous fistulas (DAVF) and arteriovenous malformations (AVM), but also certain types of spinal cord stroke and disorders involving the spinal cord venous system, such as spinal venous thrombosis.
How is a spinal angiogram performed?
The procedure is performed in a room specifically designed for angiography of the nervous system, the neuro-angiography suite. This room is equipped with machines that use x-rays to create images of blood vessels as the contrast is given through the catheter into the spinal vessels (Figure 2). The pictures are recorded and displayed on screens that the angiographers watch as they are performing the procedure.
All the recorded images are closely reviewed once the procedure is finished, and a result is given to the patient before he or she is ready to go home. Most neuro-angiography procedures are performed under light sedation. Once in the angiography suite, a combination of medications is administered, which helps the patient relax and removes uncomfortable sensations that may occur during the procedure. In addition to the sedation medications, numbing medicine is also applied in the groin area in order to eliminate local discomfort. The catheter is then inserted into an artery in the leg through a small skin incision. Accessing the leg artery gives the angiographer a direct pathway to the vessels of the spine and spinal cord without crossing or coming close to the heart (Figure 3).
The catheter is placed at the origin of each targeted blood vessels, and a small amount of contrast agent is injected. The contrast usually produces a warm, but not painful, feeling that lasts for a few seconds. During this time, x-ray pictures of the blood vessels are taken. The angiographer will perform multiple injections to obtain images of the small blood vessels of the spinal cord (Figure 4).
At the end of the procedure, the catheter is removed from the groin. The doctor holds pressure at that site for 15 to 20 minutes, and a band-aid is applied. Alternatively, a small plug is placed at the site of the puncture instead of holding pressure. The use of a plug reduces the total length of the post-procedure observation from 6 hours to 4 hours, but the plug can only be applied if the leg artery anatomy is adequate (in our service, a plug is used in about 75% of patients).
How safe is a spinal angiogram?
Diagnostic spinal angiography is very safe when performed by dedicated and experienced neuroangiographers. Our team has reviewed the patient records of 302 men and women who had a spinal angiogram in our service and found that the procedure was safe and effective. Follow the links to see the official press release and the abstract of the article that was published in the peer-viewed journal Neurology.
As is the case with any medical procedure, complications can happen during a spinal angiogram. In the past, the risk of a spinal cord stroke was often cited as a reason to avoid a spinal angiogram. This risk has now been tremendously reduced, and neurological complications occurring during spinal angiography have become very rare. In our review we found no instance of neurological complication. Nonetheless, a detailed and personalized discussion of the potential risks and benefits of the procedure is an essential step in the preparation for a spinal angiogram. This discussion takes place either during a preliminary clinic visit or immediately prior to the procedure.