What is Degenerative Disc Disease?
Degenerative disc disease is a process where the intervertebral discs undergo changes that result in a detrimental alteration in their structure and a significant reduction in their function. It usually occurs due to aging but can also occur following injury or trauma.
The Process of Disc Degeneration
From an anatomical point of view, the intervertebral disc has an outer wall called the annulus and an inner soft core called the nucleus pulposus. In the initial stages of degeneration, the outer wall may suffer small tears that do not heal sufficiently. The healed tears form scar tissue and are weaker than the original annulus. This process can make the outer disc surface weaker and weaker.
This is followed by weakness of the center of the disc. The nucleus pulposus is a soft gelatinous structure that is rich in water. It is this soft nature that enables the intervertebral discs to act as shock absorbers. With degeneration, the water content reduces and the discs become harder.
This stage is followed by collapse of the nucleus pulposus. The intervertebral discs become thinner and as a consequence the vertebrae that lie above and below the discs start to move close to each other. This can result in narrowing of the disc space and a change in the alignment of the facet joints. This can start to cause pain.
As the vertebrae get closer, calcium can deposit on their edges and result in the formation of what is known as bone spurs. These bone spurs can impinge on nerve fibers and cause pain and may also restrict the movement of the vertebra during twisting and turning. They may also result in narrowing of the spinal column called as spinal stenosis.
In the initial stages of degenerative disc disease, patients may not experience any symptoms. However, as the condition gets worse, patients can experience pain and tingling in the legs. These changes in the discs in the neck can cause arm and shoulder pain. The pain can be temporary and usually comes and goes. Certain movements such as bending and twisting can worsen the pain, and lying flat on the back can help relieve it.
A provisional diagnosis can be obtained through clinical history and examination. Diagnosis of degenerative disc disease is best achieved through x-ray. This will clearly delineate the damaged discs and will demonstrate any changes that may be seen in the vertebra. If required, more complex examinations such as CT scans and MRI scans may be required to ascertain damage to the nerve fibers.
Patients who experience pain can be effectively treated using painkillers such as non-steroidal anti-inflammatory drugs or aspirin. If there has been damage to the spinal-cord, more specialized treatment options such as discectomy and surgical decompression through endoscopic measures may need to be performed. Disc replacement with an artificial prosthesis and spinal fusion are other treatment options.