A Discogram is a test used to determine which disc or discs, if any, are related to your pain. Many people have discs that look abnormal on an MRI, but may not be related to their pain.
Discograms can be performed in the lumbar spine (low back) and cervical spine (neck). The test involves injecting dye that can be seen on x-rays into the centre of the discs. In a normal disc, without degeneration or changes, the dye stays in the centre of the disc. If the disc has torn fibres, the dye spreads into the damaged areas. If the disc is severely degenerated, the dye spreads throughout.
The second function of the test is pain assessment – information about the location and intensity of pain experienced during the injection will help your consultant to determine which discs, if any, are related to the pain you are experiencing. The reason that discograms are useful is that the correlation between degeneration seen on an MRI scan and pain is not an exact one. Discograms are not done in every case and are usually done prior to surgery.