A procedure utilized to identify if the source of pain is from the disc or in the case of multiple level herniations, which levels are the source of the discomfort.

How it's performed
Using x-ray guidance, a needle is placed in the discs of the spine at the level of interest. A pressure gauge is used to measure the pressure of the discs. Then, using contrast media, the shape of the disc is identified as the dye is injected. The procedure usually lasts 20 to 60 minutes.