The spine consists of a column of bones, known as vertebrae, connected together with a gel-filled disc between each bone to act as a shock absorber. Degenerative disc disease, also known as spondylosis, describes a spinal condition that occurs when the intervertebral discs between each vertebra dry out and shrink. Patients with degenerative disc disease exhibit symptoms, some of which they feel, but others go unnoticed until they are detected through diagnostic tests.
Cause
The discs between the vertebrae consist of a thick outer ring of cartilage with a gelatin core. Discs not only provide cushion for the bones but also allow for bending, flexion and torsion of the spine. Over time, a combination of factors contributes to the degeneration of the discs, including genetics, environmental factors, age, injuries and the presence of other diseases such as arthritis, leading to symptoms such as pain.
Effects
As the cells in the discs break down, become damaged and die, the discs lose their ability to cushion movement. In addition, the displacement of the discs changes the mechanics and the height of the spinal column because the discs contribute one-third of the spinal column's total height, according to research published by Urban and associated in the 2003 issue of "Arthritis Research and Therapy." Degeneration of the discs causes the disc space to become smaller, adds stress on the bones and stimulates bone spurs to grow, all symptoms noticeable through imaging tests. Because very few blood vessels supply the discs, they cannot repair themselves after the damage occurs.
Pain
Many patients with degenerative disc disease begin to feel back pain. The pain may become so intense that it interferes with normal activities and becomes disabling. Degenerative disc disease can occur at any age, but young adults and middle-aged people who lead active lifestyles often experience more pain than older patients such as those in their 60s, according to doctors at the Mayfield Clinic.
Sciatica
As discs degenerate, contents can leak out, causing a bulge that presses into the spinal column and compresses the sciatic nerve, the main nerve that runs from the lower back through the buttocks and down the legs. The breakdown of discs can also cause the vertebrae to shift and compress the sciatic nerve. These conditions can lead to a symptom known as sciatica, which is the occurrence of pain that radiates from the back down the legs. Sciatica can cause a mild ache to a sharp and burning pain, tingling and numbness in the leg or foot, muscle weakness and a loss of bladder control, as described by the Mayo Clinic.
Diagnostic Testing
When patients present with back pain, doctors can perform imaging studies to visualize the spine and the condition of the discs. Testing such as magnetic resonance imaging scans, radiographs or computed tomography scans can detect symptoms such as tears in the discs, bulging discs, the size of the disc space between vertebrae, the presence of bone spurs and narrowing of the spinal column.
