Sunday, December 21, 2014

Degenerative Disc Disease

Definition

Article updated and reviewed by Scott J. Luhmann, MD, Instructor in Surgery, Department of Orthopaedic Surgery, Washington University School of Medicine on June 6, 2005.

Degenerative disc disease refers to wear changes in the individual discs of the spine in any part of the spine.

Spondylosis is another term for degenerative disc disease.

Description

DDD can affect any part of the spine, although common sites are the lumbar (lower back) and cervical (neck) spine; thoracic DDD is very uncommon.

Radiographic (x-ray) findings of DDD are a narrower disc space and some osteophyte (bony outgrowth of spur) formation. As people age, these changes tend to show up on the radiographs of most men and women. However, the first imaging modality to detect changes of DDD is MRI (magnetic resonance imaging), even before plain radiographs. Loss of water content (hydration) in the invertebral disc is an early finding, which is followed by narrowing of the disc space. People in the 20’s and 30’s may already have changes to their discs but no clinical symptoms. As the aging processes continues, the prevalence of DDD increases.

In the early phases of DDD, spontaneous or post-traumatic tears, degeneration, fibrosis, and collapse of the disc may lead to failure of mechanical function. This is associated with low back pain and possible leg pain if there is nerve root impingement (radiculopathy).

As DDD progresses, there is ligamentous buckling and osteophyte development which can cause narrowing of the space for the spinal cord and nerve roots. Lumbar spinal stenosis is the narrowing of the neural canal and foramina to an extent that results in compression of the lumbosacral nerve roots or cauda equina. Acquired lumbar stenosis is caused primarily be degenerative disease of the spine. However, a congenitally narrow or small spinal canal is a common finding; when present, it requires less disc degeneration, smaller disc herniation, or osteophytes to cause symptoms.

Causes

Degenerative disc disease can result from trauma (either acute or chronic/repetitive), infection, or the natural processes of aging. It can euphemistically be referred to as the “grey hairs of the spine”.

Symptoms

The process of degeneration of the spine may lead to local pain, stiffness, and restricted activity. If there is disc herniation or rupture, one may also have leg/groin/knee pain dependent upon which nerve root is affected.

Treatment

Primary management for DDD is non-operative and includes nonsteroidal anti-inflammatory medications (NSAIDs) and exercise programs to strengthen abdominal and spinal musculature, improve aerobic fitness, and reduce lumbar lordosis (swayback).

Surgical intervention is an option when nonoperative medical management fails to adequately relieve the intolerable pain during activities of daily living which is individual-specific. It should also be considered in patients with initial signs and symptoms of progressive neurologic deterioration, specifically numbness or muscle weakness.

Classical surgical treatment for DDD which has failed nonoperative management is a spine fusion. However, advances in disc replacement technologies have made this technique a viable option for many individuals. Early investigations have demonstrated lumbar disc replacements have had outcomes equivalent to spine fusion. Not all individuals with DDD are good candidates for disc replacement surgery. Concomitant spinal deformity (scoliosis, kyphosis), history of spinal infection, posterior spinal arthritis, and multilevel disc disease are relative or absolute contraindications.

For those individuals who are not candidates for lumbar disc replacement, lumbar spine fusions have had good short-term and long-term outcomes. Fusion involve creating a solid bony connection between two or more vertebrae anteriorly, posteriorly, or both.

In a spine fusion procedure, the surgeon joins two or more adjacent vertebrae. Bone taken from other parts of the body, usually the pelvis just above the hip joint, is placed across the vertebrae. Plugs of bone shaped like hockey pucks or cages made of metal or plastic are used between the vertebrae anteriorly. Posteriorly the bone is ground up into small pieces and laid down over the spine. The vertebrae and bone graft grow together as healing progresses, eventually forming a single unit without motion across them.

If the spine is in overall good position, spinal implants may not be necessary. So while not all spinal fusions require implants, many patients whose spines are weakened by injury or disease or whose deformities must be corrected are treated with internal fixation or spinal implants. If the spine needs to be placed and maintained in a new position, spinal implants will typically be necessary. The implants can include rods, screws, and hooks to fixate and stabilize the spine. Various types of implants are used depending on the problem that required the fusion, the patient's age, and the surgeon’s judgment. These implants are usually left implanted indefinitely to minimize the possible loss of spinal alignment. The development of a spine fusion may take up to one year during which time physical activity may be limited and a spine brace may be recommended.

Fusion surgery is inherently more complicated, more painful, and riskier than procedures such as discectomy and laminectomy. There is no consensus in the medical community as to the appropriate indications for fusion surgery.

Questions

What is the problem with the lumbar spine?

Is there significant narrowing and compression?

What treatments do you recommend?

What operative treatments are options?

Is spinal fusion preferable to laminectomy and other procedures?

Will spinal implants be used? If so, what kind and what is their purpose?

What are the possible complications?

What are the chances the preoperative symptoms will be improved or eliminated?

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Editorial review provided by VeriMed Healthcare Network.

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