Degenerative disc disease is not really a disease, but rather a term used to describe the normal changes in your spinal discs as you age; it occurs when the discs break down, or degenerate. The discs act as shock absorbers for the spine, allowing it to flex, bend, and twist. These age-related changes include the loss of fluid in your discs, which reduces the ability of the discs to act as shock absorbers and makes them less flexible. Loss of fluid also makes the disc thinner and narrows the distance between the vertebrae. These changes can take place throughout the spine, but it most often occurs in the discs in the lower back (lumbar region) and the neck (cervical region).

The changes in the discs can result in: Osteoarthritis, the breakdown of the tissue (cartilage that protects and cushions joints), herniated disc (an abnormal bulge or breaking open of a spinal disc), or spinal stenosis (the narrowing of the spinal canal, the open space in the spine that holds the spinal cord). These conditions may put pressure on the spinal cord and nerves, leading to pain and possibly affecting nerve function.

Disc degeneration is more likely to occur in people who smoke cigarettes, who do heavy physical work and who are obese. A sudden acute injury such as caused by a fall may cause a disc to herniate and may also begin the degeneration process. As the space between the vertebrae gets smaller, there is less padding between them, and the spine becomes less stable. The body reacts to this by constructing bony growths called bone spurs, which can put pressure on the spinal nerve roots or spinal cord, resulting in pain and affecting nerve function.

Symptoms of degenerative disc disease are back or neck pain or numbness and tingling in your leg or arm. Many people have no pain, while others with the same amount of disc damage have severe pain that limits their activities. Where the pain occurs depends on the location of the affected disc. Pain may start after a minor injury, or after a routine motion such as bending to pick up an item. Surprisingly, pain associated with degenerative disc disease may begin gradually for no apparent reason and steadily worsen.