Discography

Discography (a discogram) is a specialised test in which contrast dye is injected into the centre of one or more intervertebral discs to assess whether a disc is a source of pain. It is used only in carefully selected cases, usually when other investigations have not clarified the origin of persistent back pain and a specific decision about that disc needs to be made. It is a test that has genuine uses but also well-recognised limitations and is not part of routine assessment.

Under X-ray guidance, a fine needle is placed into the middle of the disc and contrast dye is slowly injected. Two kinds of information can result. First, the pattern of the dye on X-ray or a follow-up CT shows the internal structure of the disc, including any tears. Second — and more contentiously — the test notes whether injecting the disc reproduces the person's familiar pain, while a normal neighbouring disc does not. Reproduction of typical pain has been taken to suggest that disc is symptomatic, though this interpretation is debated.

Discography is a more involved procedure carried out by a specialist. The skin is numbed and imaging guides the needle into the disc; you may feel pressure and, at times, a reproduction of your usual pain, which is part of what is being assessed, so you will be asked to describe what you feel. Because it involves entering the disc, it is done under sterile conditions with careful technique, and specific after-care and monitoring are provided. You will usually need someone to take you home.

Disc pain is notoriously hard to pin down, and discography is one of the few tests that attempts to address the disc directly. However, the evidence around it is mixed: results can be difficult to interpret, and it carries more risk than most diagnostic injections. For these reasons it is used selectively and cautiously, as one input among several, and always interpreted by the specialist alongside the wider clinical and imaging picture rather than as a standalone verdict.

• —NICE — Low Back Pain and Sciatica in Over 16s (NG59)
• —Faculty of Pain Medicine, Royal College of Anaesthetists — Standards
• —British Association of Spine Surgeons (BASS)

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.