Degenerative disc disease (DDD) refers to gradual deterioration of the intervertebral discs between the vertebrae. DDD is a misnomer as it is not actually a disease but a condition that affects the strength, resiliency and structural integrity of the intervertebral discs due to advancing age, trauma, injury, repetitive movement, improper posture, or poor body mechanics. DDD is commonly seen in individuals over 50 years of age. Most of them are usually not aware about their condition until they are examined for some other related health condition.
The intervertebral disc is composed of an inflexible ring called the annulus fibrosis which encloses a gelatinous inner structure called the nucleus pulposus. The discs are kept in position with the help of endplates between two vertebral bodies. The intervertebral discs act as shock absorbers.
As we age, the rate at which the old, worn out cells are replaced is gradually reduced, resulting in the degenerative changes in the discs which can also be accelerated by injury or trauma.
These structural changes can cause a sequence of other changes, resulting in nerve compression and pain due to reduction in the disc height, and presence of bone spurs or bony overgrowths (osteophytes). Other conditions such as spinal stenosis and osteoarthritis (spondylosis) can also affect the intervertebral joints and spinal stability.
Symptoms
Every patient is different and it is important to realize that not everyone develops symptoms as a result of degenerative disc disease. When the condition becomes painful or symptomatic, it can cause several different symptoms due to the compression of the nerve roots. Depending on the location of the degenerative disc, it could cause back pain, radiating leg pain, neck pain, and radiating arm pain.
As the discs between the intervertebral bodies start to degenerate, the entire lumbar spine loses flexibility resulting in back pain and stiffness.
Diagnosis
The diagnosis of degenerative disc disease comprises of complete medical history and physical examination. Examination of the back for flexibility, range of motion, and the presence of certain signs that suggest nerve root injury help detect the degenerative changes. This is done by testing your muscle strength and your reflexes to make sure that they are still functioning normally.
A series of X-rays may also be performed. If degenerative disc disease is present, the X-rays will often show a narrowing of the spaces between the vertebral bodies, which indicates that the disc has become very thin or has collapsed. Bone spurs formed around the edges of the vertebral bodies and around the edges of the facet joints in the spine can also be seen on an X-ray. As a result, the space available for the nerve roots begins to shrink. The nerve roots exit the spinal canal through a bony tunnel called the neural foramen and it is at this point the nerve roots are especially vulnerable to compression.
In most cases a MRI or a CT scan may be ordered to evaluate the degenerative changes, determine disc herniation and nerve root compression. A CT scan is often used to evaluate the anatomy in the spine which can show the amount of space available for the nerve roots as well as the space within the neural foramina and spinal canal.
Treatment
Both surgical and nonsurgical treatment options are available for the management of degenerative conditions. The choice of treatment depends on various factors such as age of patient and severity of disease.
Nonsurgical treatment – For people with no evidence of nerve root compression or muscle weakness, conservative treatment such as medication, rest, exercise and physical therapy are usually recommended.
Surgical treatment – Surgery is offered only after conservative treatment options fail to adequately relieve the symptoms of pain, numbness and weakness over a significant period of time. Decompression of the spinal cord along with a discectomy and fusion will be performed to remove the affected disc and fuse the adjoining vertebrae in order to stabilize the spine.
