Nearly everyone’s spinal discs show signs of wear as they age. Not everyone, however, will have degenerative disc disease. Not actually a disease, this is a condition in which a damaged disc causes pain. A wide range of symptoms and severity is associated with this condition.
The discs are like shock absorbers between the bones of the spine and are designed to help the back stay flexible while resisting terrific forces in many different planes of motion. Each disc has two parts:
- A firm, tough outer layer, the anulus fibrosus. The outer portion of this layer contains nerves. If the disc tears in this area, it can become quite painful.
- A soft, jellylike core, the nucleus pulposus. This part of the disc contains proteins that can cause the tissues they touch to become swollen and tender. If these proteins leak out to the nerves of the outer layer of the disc, they can cause a great deal of pain.
Unlike other tissues of the body, the disc has very low blood supply. Once a disc is injured, it cannot repair itself, and a spiral of degeneration can set in with three stages that appear to occur over 20 to 30 years:
- Acute pain makes normal movement of the back difficult
- The bone where the injury occurred becomes relatively unstable. Over a long period of time, the patient will have back pain that comes and goes.
- The body restabilizes the injured segment of the back. The patient experiences fewer bouts of back pain.