A discography, or discogram, is an enhanced X-ray examination of the intervertebral discs. This test is performed to determine which, if any, discs have structural damage that is the source of a patient’s low back pain. Dye is injected into the center discs and is clearly visible using fluoroscopic x-ray film. A healthy disc should allow for a certain amount of dye to enter the disc without any dye leaving the disc space and should also not cause any pain. If a disc has an annular tear or rupture, dye will be seen leaving the disc. An unhealthy disc may not accept as much dye as a healthy disc so the volume allowed to enter the disc is also important to note. This test is usually done as part of surgical planning to confirm or help the surgeon locate the discs causing pain.
Not all degenerative discs are the source of pain. A positive discogram is important to confirm levels involved and more than one level needs to be tested including one that is a negative control. If dye injected into the disc reproduces a patient’s back pain, this is indicative that surgically treating this disc will resolve that pain. This is done to avoid additional surgery if multiple disc appear degenerative on MRI but do not all cause pain or establish that certain levels need to be surgical addressed to solve the entire problem. This test is done under fluoroscope and the patient has a mild sedative medication along with local anesthesia to make the patient as comfortable as possible. It is important the patient is awake and alert enough to discuss what they experience during the test with the physician. Risks associated with a discogram include x-ray exposure, infection inside the disc from the needle and an allergic reaction to the dye.