Some patients are treated with rhizotomy, in which the culprit nerve is cauterized. Scans, such as magnetic resonance imaging, show the condition of lumbar vertebrae and the collagen discs that lie between them. The disc may be herniated, pushing on the nerves exiting the spinal cord. The damage may not be more subtle than a rupture. The disc shrinks a little and that's why people get shorter as they get older.
Pain comes from inflammation and irritation of local nerve endings.
Before suggesting a treatment, doctors do a special test to be certain that the problem is a degenerated disc at a specific level. During the so-called discogram, dye is injected into the suspect disc. If the dye spreads diffusely, the pressures within the disc measure lower than normal and the procedure elicits the same pain the patient typically feels, a treatment at that level stands a good chance of improving symptoms. Discs at other levels are tested also to be sure that the problem is limited. Limited damage is treated more successfully than widespread damage.