Degenerative Disc Disease - Degenerative Disk Disease

Degenerative disc disease (DDD) is breakdown of an intervertebral disc of the spine. It may cause acute or chronic low back or neck pain. The typical radiographic findings in DDD are black discs, disc space narrowing, vacuum disc, end plate sclerosis, and osteophyte formation. DDD can greatly affect quality of life. Disc degeneration is a disease of micro/macro trauma and of aging, and though for most people is not a problem, in certain individuals a degenerated disc can cause severe chronic pain if left untreated.

Signs and symptoms

With symptomatic degenerative disc disease, chronic low back pain sometimes radiates to the hips, or there is pain in the buttocks or thighs while walking; sporadic tingling or weakness through the knees, hands, and fingers may also be evident. Similar pain may be felt or may increase while sitting, bending, lifting, and twisting. Chronic neck pain can also come from the cervical spine, with pain radiating to the head, shoulders, arms and hands.

After an injury, some discs become painful because of inflammation and the pain comes and goes. Some people have nerve endings that penetrate more deeply into the anulus fibrosus (outer layer of the disc) than others, making discs more likely to generate pain. In the alternative, the healing of trauma to the outer anulus fibrosus may result in the innervation of the scar tissue and pain impulses from the disc, as these nerves become inflamed by nucleus pulposus material. Degenerative disc disease can lead to a chronic debilitating condition and can have a serious negative impact on a person's quality of life. When pain from degenerative disc disease is severe, traditional nonoperative treatment may be ineffective.

Mechanisms

Degenerative discs typically show degenerative fibrocartilage and clusters of chondrocytes, suggestive of repair. Inflammation may or may not be present. Histologic examination of disc fragments resected for presumed DDD is routine to exclude malignancy.

Fibrocartilage replaces the gelatinous mucoid material of the nucleus pulposus as the disc changes with age. There may be splits in the anulus fibrosus, permitting herniation of elements of nucleus pulposus. There may also be shrinkage of the nucleus pulposus that produces prolapse or folding of the anulus fibrosus with secondary osteophyte formation at the margins of the adjacent vertebral body. The pathologic findings in DDD include protrusion, spondylolysis, and/or subluxation of vertebrae (sponylolisthesis) and spinal stenosis.

Diagnosis

Treatment

Often, degenerative disc disease can be successfully treated without surgery. One or a combination of treatments such as physical therapy, anti-inflammatory medications such as nonsteroidal anti-inflammatory drugs, traction, or epidural steroid injection often provide adequate relief of troubling symptoms.

Surgery may be recommended if the conservative treatment options do not provide relief within two to three months. If leg or back pain limits normal activity, if there is weakness or numbness in the legs, if it is difficult to walk or stand, or if medication or physical therapy are ineffective, surgery may be necessary, most often spinal fusion. There are many surgical options for the treatment of degenerative disc disease. The most common surgical treatments include:

New treatments are emerging that are still in the beginning clinical trial phases. Glucosamine injections may offer pain relief for some without precluding the use of more aggressive treatment options. In the US, artificial disc replacement is viewed cautiously as a possible alternative to fusion in carefully selected patients, yet it is widely used in a broader range of cases in Europe, where multi-level disc replacement of the cervical and lumbar spine is common. Adult stem cell therapies for disc regeneration are in their infancy. Investigation into mesenchymal stem cell therapy knife-less fusion of vertebrae in the United States began in 2006.