The only valid diagnostic procedure for determining if a disc is the pain generator, is a provocative discogram.
A discogram is an imaging-guided procedure in which a contrast agent is injected into the inner core of the vertebral disc. You will need to be admitted to hospital as a day patient for this procedure.
An intravenous cannula (a tube) is inserted, containing a fine needle. This needle is passed into the relevant vertebral discs. A small amount of pain relief medication may be used to ensure minimum discomfort for the patient. However, it is imperative that the patient is able to answer questions clearly and precisely during the procedure.
During the procedure, the needle may brush against the facet joints behind the spine. This often causes a deep, aching pain for a short period of time. Sometimes, the needle may brush against the side of the ‘exiting nerve root’, which causes a sharp, ‘electrical’ or ‘hot’ pain to shoot down the leg. The chance of this happening is small, but it is important you tell the doctor if you experience this sort of pain. They will then manipulate the needle away from the nerve, to avoid nerve damage.