The process of degeneration of the intervertebral discs causes many problems in the spine. Everything you do during the day while being upright tests the spine’s ability to support your body weight. Minor injuries to the 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-it begins to degenerate.
The main problem with degenerative disc disease lies within one or more of the intervertebral discs. There is a disc between each vertebra in the spine. Much of the mechanical stress of everyday movements is transferred to the discs. The intervertebral discs are designed to absorb pressure and keep the spine flexible by acting as cushions during body movement-similar to shock absorbers. Without the cushion effect of the discs, the vertebrae in your spine would not be able to absorb stresses or provide the movement needed to bend and twist.
A healthy intervertebral disc has a great deal of water in the nucleus pulposus (the center portion of the disc). The water content gives the nucleus a spongy quality and allows it to absorb spinal stress. Excessive pressure or injuries to the disc can cause the injury to the annulus (the outer ring of tough ligament material) that holds the vertebrae together. The annulus is generally the first portion of the disc to be injured. Small tears show up in the ligament material of the annulus. These tears heal by scar tissue, which is not as strong as normal ligament tissue. The annulus becomes weaker over time as more scar tissue forms. This can lead to damage of the nucleus pulposus. It begins to lose its water content and dry up.
Loss of water content causes the discs to lose some of their ability to act as cushions. This can lead to even more stress on the annulus and still more tears as the cycle repeats itself. As the nucleus loses its water content, it collapses, allowing the two vertebrae above and below to move closer to one another. This results in a narrowing of the disc space between the two vertebrae. As this shift occurs, the facet joints (located at the back of the spine) are forced to shift. Shifting changes the way the facet joints work together and can cause problems as well.
Bone spurs, sometimes called osteophytes, may begin to form around the disc space. These can also form around the facet joints. This is thought to be due to the body’s response to try 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.
The most common early symptom of degenerative disc disease is usually pain in the back 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 begin to affect all parts of the spine. Problems thought to arise from the degenerating disc itself include discogenic pain, and bulging discs.
Discogenic pain is a term back specialists use when referring 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 usually causes pain felt in the lower back. It may also feel like the pain is coming from your buttock area and even down into the upper thighs. The experience of feeling pain in an area away from the real cause is common in many areas of the body, not just the spine. For instance, a person with gallstones may feel pain in the shoulder or a person experiencing a heart attack may feel pain in the left arm. This is referred to as radiation of the pain. 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. Abnormalities, such as bulging or protruding discs, are seen at high rates on MRIs in patients both with and without back pain. Some discs most likely begin to bulge as a 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. View animation of bulging disc.
Before your doctor can diagnose your condition and design a treatment plan, a complete history and physical exam are necessary. There are so many possible causes of pain. It is important to determine what is and is not at the root of the problem.
You may be asked to take a variety of diagnostic tests. The tests are chosen based upon what your physician suspects is causing your pain. The most common diagnostic tests used to diagnose degenerative disc disease are ordinary X-rays and MRI scans. If your doctor suspects disc degeneration, X-rays can be used to verify a decrease in the height of space between vertebrae, bone spurs, facet hypertrophy (enlargement), and instability during flexion or extension of limbs. An MRI can verify loss of water in a disc, facet joint hypertrophy, stenosis, or a herniated disc.
Treatment will depend on the seriousness of your condition. Some problems need immediate attention-possibly even surgery. The vast majority of back problems do not require surgery. Treatment for your back may be as simple as reassuring you that it is not a serious problem and doing nothing but watching and waiting. In most cases, simple therapies, such as mild pain medications and rest are effective in relieving the immediate pain.
Your doctor may have you work with a physical therapist. A well-rounded rehabilitation program assists in calming pain and inflammation, improving your mobility and strength, and helping you do your daily activities with greater ease and ability.
An epidural steroid injection (ESI) can be used to relieve the pain of stenosis and irritated nerve roots, as well as to decrease inflammation. Injections can also help reduce swelling from a bulging or herniated disc. The steroid injections are a combination of cortisone (a powerful anti-inflammatory steroid) and a local anesthetic that are given through the back into the epidural space. ESIs are not always successful in relieving symptoms of inflammation. They are used only when conservative treatments have failed.