People who complain of disabling low back pain may have had an MRI scan which has shown small disc bulges, degenerative changes (wear and tear) or tears in the intervertebral disc, although these findings may not necessarily be the cause of their pain. Lumbar discography is an investigation that can determine whether or not the intervertebral disc is actually responsible.
The intervertebral disc is the structure that is between vertebrae (bones of the spine). It acts as both a spacer and a shock absorber. The disc is composed of two parts: a soft gel-like centre (the nucleus pulposus) surrounded by a tougher fibrous wall (the annulus fibrosis).
Sometimes the intervertebral discs can lose their flexibility,elasticity and shock-absorbing characteristics, while the tough layer of ligaments that surrounds the disc may weaken and no longer be able to contain the gel-like substance in the centre. This can cause inflammation to the surrounding area and some of these discs can be a source of continuing back pain and pain in the legs.
If the symptoms are severe and chronic and have not responded to physiotherapy, the disc can be tested to diagnose whether it is the source of the pain the patient is experiencing (discography).