Discography is a procedure that is sometimes used to help evaluate patients with back pain that has not responded to conservative care. It commonly is used before surgery to confirm the levels causing the symptoms.
If someone has disabling pain in the lower back, the groin, the hip or the leg, discography may be used to find the source of the pain. The goal of discography is less about the structure of the disc (the gel-filled pad that cushions the vertebrae) than it is about how the disc is working.
Magnetic resonance imaging (MRI) and computer tomography with myelogram are useful for viewing the structure of the disc. They do not, however, help in identifying what is generating the pain. A discogram, on the other hand, is used to cause pain in a sensitive disc, thus showing where the pain is coming from. This is particularly helpful before surgery to confirm that the bones that are being fused are the ones where the pain is coming from. If the patient's pain cannot be duplicated during the discogram, then addtional diagnostic studies may be needed.