The area of the spine in the neck is called the cervical spine. It extends from the base of the skull to the upper torso and contains seven vertebrae. In between each of the vertebrae is a structure called an intervertebral disc. A spinal disc is like a jelly donut. It's composed of a tough outer layer and a jelly-like center. The purpose of the disc is to act like a shock absorber for the spine during motion and provide support for the vertebrae.

Over time, the intervertebral discs start to degenerate. The water content inside the disc decreases and tiny cracks develop in the outer layer. Researchers say this process begins as early as the second decade of life. Eventually, the disc starts to shrink and the space between the vertebrae decreases. This is known as degenerative disc disease.

As the cervical spine loses some of its support, more pressure is placed on the intervertebral discs, causing even further wear and tear. Sometimes part of the jelly-like center protrudes backwards toward the spinal canal. This is a herniated disc. The contents of the herniated disc can press against the spinal nerve roots, causing pain, weakness or numbness in the shoulders, neck or arms. A herniated disc can also occur from a sudden, forceful movement or injury.

Spinal disc problems are fairly common, however, many patients are asymptomatic (they don't have any symptoms from the condition). Researchers believe evidence of degenerative disc disease can be seen in 25 percent of people under 40 and in 60 percent of those over 40. A herniated disc can be found in 10 percent of those under 40 and five percent of people over 40.

Treating Cervical Disc Degeneration

Initially, doctors may try conservative treatment for patients with degenerative cervical discs. Bed rest, limitation of movement and over-the-counter pain relievers are helpful for many patients. Prescription medications may also be used to relieve pain and inflammation. Some patients need physical therapy.

When conservative treatments aren't helpful, doctors may recommend surgery. The standard treatment for disc degeneration and/or herniated discs is an anterior cervical discectomy, or surgical removal of the damaged disc and any disc fragments. The procedure takes the pressure off the affected spinal nerve roots. But since the cushioning structure is removed, doctors must use grafts of bone and metal to support the upper and lower vertebrae. This is called a fusion because the bone grafts eventually form a solid bone, permanently fusing the two vertebrae into one unit.

Cervical discectomy and fusion can be a very effective treatment for many patients. However, there are some drawbacks to the procedure. Since the two vertebrae are fused, the patient loses motion in that segment of the spine. In addition, fusion changes the dynamics in the remaining area of the cervical spine. Researchers have found the intervertebral discs of the adjacent vertebrae are likely to suffer increased wear and tear.

An Artificial Cervical Disc

An artificial cervical disc is a man-made replacement for the natural disc. Several of the devices are in development or clinical trials. One of those under study is the NeoDisc™ (produced by NuVasive®).

The NeoDisc is designed to replicate the function of the natural cervical disc - providing a cushion for the spine and retaining similar natural motion in the affected area of the neck. Orthopedic Spine Surgeon, Jeffrey Cantor, M.D., says the device is placed the same way a bone graft wound be inserted for fusion. After the surgery, as the area heals, the bone will grow around the artificial disc and it will become a permanent structure in the spine.

The company recently began clinical trials with NeoDisc. Participants will be divided into groups. One group will receive the NeoDisc and one will receive standard discectomy and fusion. To qualify, patients must have symptoms in only one cervical disc and have failed conservative treatment lasting six weeks or longer. For more information, log onto the web at http://www.neodiscstudy.com, or call (866) 840-6768.

For information about the NeoDisc™ or the clinical trial, log onto http://www.neodiscstudy.com, or call (866) 840-6768.

For information on cervical disk degeneration or herniation:

American Academy of Orthopaedic Surgeons, public website