What is degenerative disc disease?
Degenerative disc disease is a spinal condition caused by the breakdown of your intervertebral discs. As you age, your spine begins to show signs of wear and tear as your discs dry out and shrink. These age-related changes can lead to arthritis, disc herniation, or spinal stenosis, which can put pressure on your spinal cord and nerves and may cause back pain. Several treatments can help relieve the pain. Each treatment offers benefits, but each has limitations. You and your doctor should determine which treatment is best for you.
Degenerative disc disease (also called spondylosis) is a general term used to describe changes that can occur along any area of the spine (cervical, thoracic, lumbar) as you age, but is most common in the lumbar area. It’s not actually a disease, but rather a condition in which your discs “degenerate,” or lose their flexibility and ability to cushion your spine. Your discs don’t have a good blood supply, so once injured it can’t repair itself.
These age-related changes include:
- Discs dry out and shrink – made of about 80% water, as you get older they slowly lose water. This loss of flexibility puts more stress on the annulus.
- Small tears occur in the annulus – sometimes some of the gel-like material, or nucleus pulposus, comes out through a tear in the wall and touches the nerves. This material has many inflammatory proteins that can inflame the nerves and cause pain. These tears also affect the nerves in the annulus, and small movements, called micro-movements, can cause discogenic pain. Over the years the proteins eventually dry up, and the discs become stiffer; in many people this results in less pain by the time they are in their sixties.
- Disc space gets smaller – due to the loss of water in the discs the distance between vertebrae begin to collapse, which is why we get shorter as we age.
- Bone spurs grow – without the discs holding apart the vertebrae, they can rub on each other causing abnormal bone growths.
- Spinal canal narrows – the stresses of all the above changes causes the ligaments and facet joints to enlarge (hypertrophy) as they try to compensate and spread the load over a larger area. This over-growth causes the spinal canal to narrow, which can compress the spinal cord and nerves causing pain.