By: Dale J. Buchberger, PT, DC, CSCS
It is not uncommon for a patient to come in the office and state that they have been diagnosed with “degenerative disc disease” of either their neck or lower back. While degenerative disc disease is not really a disease but a term used to describe the acceptable and age related changes to the spinal discs. The spinal discs serve as shock absorbers and ligaments between the bones (vertebrae) of the spine and provide stability and flexibility while resisting high multi-directional forces. Each disc from the neck to the lower back has two parts: A tough, dense outer layer called the annulus fibrosus. The outer portion of this layer contains pain sensitive nerves. If the disc tears in this area, it can become a source of back or neck pain. The inside is a soft, jelly-like core called the nucleus pulposus. If this nucleus leaks out and makes contact with the nerves of the outer layer of the disc they can stimulate pain in the specific region.
It is not uncommon for several conditions to coexist in the spine once the process of degenerative disc disease has begun. Osteoarthritis (degenerative joint disease), is the breakdown of the cartilage that protects and cushions joints. A herniated disc is an abnormal bulge in the outer layer of the disc. This puts added stress on the spinal joints leading to osteoarthritis. As the arthritic spurs grow they begin to narrow the central spinal canal leading to spinal stenosis.
Because we are protein and mechanical based entities this also means we are finite and subject to expiration. Consequently as we age, our spinal discs gradually break down, or degenerate, resulting in degenerative disc disease. These age-related changes include, dehydration of the spinal discs. This reduces the shock absorbing ability of the discs and leaves the spine less flexible. Loss of fluid also makes the disc thinner and narrows the distance between the vertebrae resulting in age related height loss.
As the disc fibers begin to degenerate they weaken allowing tiny tears to occur in the outer layer of the disc. The jelly like material inside the disc may be forced out through the tears in the annulus, causing the disc to bulge or rupture producing disc fragments. A herniated disc may also occur from an acute injury such as a fall, motor vehicle accident or lifting a heavy weight incorrectly. In this case the degenerative process is given a head start by the acute trauma.
Degenerative disc disease may result in back or neck pain, but this varies from person to person. Many people have no pain, while others with the same amount of disc damage will have severe pain limiting their activities. Where the pain occurs depends on the location of the affected disc. A degenerated disc in the neck area may result in neck, arm or hand pain, while a degenerated disc in the lower back may result in lower back, buttock, leg or foot pain. The pain often gets worse with bending over, reaching overhead, or lifting and twisting.
The pain of degenerative disc disease may be stimulated by a severe injury such as a car accident, a minor injury such as a slip and fall, or a trivial activity such as bending over to pick up a pen. It may also start gradually for no known reason and worsen over time.
In the past degenerative disc disease was diagnosed with a medical history and physical examination in combination with your age. Today a definitive diagnosis of degenerative disc disease is made with a combination of spinal x-rays and magnetic resonance imaging or MRI. X-rays will show a narrowing of the discs with arthritic spurring off of the vertebrae. The MRI will show “signal changes” that are specific to the dehydration of the disc or “desiccation”.
Treatment depends on whether the damaged disc has resulted in other conditions, such as osteoarthritis, a herniated disc, or spinal stenosis. Physical therapy and exercises for strengthening and stretching the back are often recommended, and in some cases surgery may be recommended. Surgery for degenerative disc disease usually involves removing the damaged disc. In some cases, the bone is then permanently joined or fused to protect the spinal cord. In rare cases, an artificial disc may be used to replace the disc that is removed.
Nearly everyone shows some signs of wear and tear on the spinal discs as they age. Pain that is worse when sitting and gets worse when bending, lifting or twisting can indicate degenerative disc disease. Pain may feel better with gentle movement such as walking. Remember that symptoms may come and go getting progressively worse with each episode. If pain, numbness or tingling begins to travel into the arms or legs you should seek the opinion of a healthcare provider.