Although magnetic resonance imaging (MRI) is a very good tool for showing disc abnormalities, it does not allow your health care provider to directly determine if the abnormalities are causing your pain. Studies in which MRI was performed in people without back pain show that 35% to 52% of these patients had one or more abnormal discs. In a study of people without back pain but who were of the same age and occupation as a group of back pain patients, 76% had abnormal MRIs. These studies raise the question: If MRI shows that a back pain patient has an abnormal disc, is that abnormality related to the pain or just an abnormality similar to that seen in people without pain?
Discography is a very specific tool that may help your doctor determine if the abnormal disc is causing your pain. Many doctors find discography is helpful in identifying the source of pain. Because discography is an invasive procedure (it involves putting needles into the disc), it is not performed early in the diagnostic and treatment process.
Generally, patients who undergo discography have not gotten satisfactory pain relief from nonoperative measures such as medication, physical therapy and modified activities. They usually have had back pain for at least 4 to 6 months.
Discography is usually used in patients who are being evaluated to determine a specific cause of pain so a new treatment plan (possibly including surgery) can be developed.
How is it Done?
You may receive a light sedative to help you relax during the procedure. The following is a description of one method of performing discography; the exact procedure may vary depending on your medical history and the preference of the health care provider performing the test.
Discography is usually performed in a procedure room that has equipment for X-ray imaging of the discs as the test is performed. You will be asked to lay on one side and may be rolled slightly forward on a table. Your skin will be wiped at the site of the injection with a cleansing antiseptic agent. Typically, the lowest two or three lumbar disc levels are injected. The doctor may inject an anesthetic into the skin to reduce the pain of the needles passing through tissue. In some cases, antibiotics are given intravenously before and after the procedure.
A needle is inserted through the skin and muscle and comes to rest on the outer layer of the disc. During the process of placing the needles, imaging studies called fluoroscopy (similar to X-ray) are used to help the health care provider see where the needles are located along the path to the disc. A second needle is passed through the first one and into the center of the disc. This process is repeated at each level that is to be injected. In some cases, the doctor may decide to inject an additional level and will place needles at that location after the initial injections. Contrast (a liquid that shows up on X-ray), is injected into the center of each disc. If the disc is normal, the contrast remains in the center of the disc. If the disc is abnormal, the contrast spreads through the tears in the disc.
As each disc is injected, you may be asked to rate the intensity of the pain that the injection causes, if any. You may also be asked if the pain is similar to your usual symptoms in terms of location and the type of pain you are experiencing. This procedure is repeated for each disc that is injected. CT scanning is often performed after disc injection. This gives your health care provider more information about the exact pattern of the spread of the contrast through or out of the disc. Widespread disc degeneration is identified by the contrast spreading throughout the disc space.
The injection procedure generally takes about 30 to 45 minutes. After the disc injections, you may be kept for observation. It is advisable that you have someone drive you home. In some cases, pain from the injection can persist for several hours. There may be some residual muscle pain from passing the needles. If you experience intense pain, call your health care provider.
For more information on Discography, contact Comprehensive Pain Management in South Kingstown, RI.