Everything you do during the day while being upright tests the spine’s ability to support your body weight. Minor injuries to a disc may occur and not cause pain at the time of the injury. These repeated daily stresses and minor injuries can add up over time and begin to affect the discs in your spine. The disc eventually begins to suffer from the wear and tear and it begins to degenerate. Degeneration of the discs in the spine can cause many painful problems.
A healthy intervertebral disc has a great deal of water in its center. The water content gives the disc a spongy quality, which enables it to absorb stresses put on the spine. Too much pressure or injury to the disc can damage the ligament that holds the vertebrae immediately above and below the disc together. This is generally the first portion of the disc to be injured. Small tears show up in the ligament material. These tears heal and form scar tissue, which is not as strong as normal ligament tissue. The ligament becomes weaker over time as more scar tissue forms. In time, the disc begins to lose its water content and dry up.
Loss of water causes the disc to lose some of its ability to act as a cushion. This can lead to even more stress on the ligament and still more tears as the cycle repeats itself. As the disc loses its water content, it collapses, allowing the vertebrae above and below it to move closer together. This causes the space between the bones to narrow, changing the way the facet joint works.
Bone spurs, sometimes called osteophytes (os-tee-oh-fights), may begin to form around the disc space. These can also form around the facet joints, which may be your body’s way of trying to stop the excess motion at the spinal segment. The bone spurs can become a problem if they start to grow into the spinal canal and press into the spinal cord and spinal nerves. This condition is called spinal stenosis (sten-o-sis).
The most common early symptom of degenerative disc disease is back pain that spreads to the buttocks and upper thighs. When doctors refer to degenerative disc disease, they are usually referring to a combination of problems in the spine that start with damage to the disc, but eventually affect all parts of the spine. Problems thought to arise from the degenerating disc itself include discogenic pain, and bulging discs.
Discogenic pain refers to pain caused by a damaged intervertebral disc. A degenerating disc may cause mechanical (or structural) pain. As the disc begins to degenerate, there is some evidence that the disc itself becomes painful. Movements that place stress on the disc can result in back pain that appears to come from the disc. This is similar to any other body part that is injured, such as a broken bone or a cut in the skin. When these types of injuries are held still there is no pain, but if you move them they hurt.
Discogenic pain is usually felt in your lower back. The pain may also feel like it is coming from your buttocks and even down into your upper thighs. The experience of feeling pain in an area away from the real cause is common in many parts of the body, not just the spine. For example, a person with gallstones may feel pain in their shoulder, and a person having a heart attack may feel pain in their left arm. This is referred to as radiation of the pain because the pain radiates, or spreads out, to other parts of the body. It is very common for pain produced by spine problems to be felt in different areas of the body – including the back.
Bulging discs are fairly common in both young adults and older people. They are not cause for panic. Bulging discs are frequently seen in people with and without back pain. In some cases, bulging discs are part of both the aging process and the degeneration process of the intervertebral disc. A bulging disc is not necessarily a sign that anything serious is happening to your spine. A bulging disc only becomes serious when it bulges enough to cause narrowing of the spinal canal. If there are bone spurs present on the facet joints behind the bulging disc, the combination may cause narrowing of the spinal canal in that area. This is sometimes referred to as segmental spinal stenosis.