During discography, 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. This process is repeated at each level that is to be injected. Contrast material (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. The pain provoked by the injection should be temporary. CT scanning is 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.
Specific indications for discography include the following:
- Continued acute pain when other tests have been unable to determine a suspected disk as a source of the pain.
- Assessment of abnormal disks or recurrent pain from a previously operated disk or lateral disk herniation
- Examination of patients for whom back surgery has failed.
- Inspection of disks preceding fusion to establish whether the disks of the anticipated fusion segment are symptomatic and whether the disks adjacent to this segment can support a fusion.
- Evaluation of approved patients for minimally invasive surgery who have a confirmed disk herniation.