The Cervical Spine and Disc Degeneration

The cervical spine (neck) is the area of the spine from the upper back to the base of the skull. Small, horizontal bone segments (called vertebrae) are attached to the spine. Tiny joints (called facet joints) enable the spine to bend. In between each of the vertebrae is a small, cushioning disc. The discs act like shock-absorbers for the spine and prevent the vertebrae from collapsing.

The spinal discs are composed of a tough covering of cartilage (called the annulus) and an inner gel-like substance (called the nucleus). Normally, the spinal discs contain a significant amount of water. With age, however, the water content decreases and the disc loses some of its cushioning ability (called disc degeneration). The disc also shrinks, causing the space between the vertebrae to get smaller. In addition, the outer covering of the disc may start to wear and develop tiny cracks. Some of the inner contents of the disc may leak out through the cracks into the space which holds the spinal nerves (disc herniation). That can put pressure on the nerves and cause pain, numbness, tingling and weakness. A herniated cervical (neck) disc can cause symptoms in the neck or shoulder. Sometimes the pain causes headaches or shoots down the arm.

Treating Herniated Cervical Discs

Initially, doctors will try conservative treatments for a herniated cervical disc. Patients may be advised to rest, use a neck collar and take anti-inflammatory medications. Physical therapy, exercises and injections of steroids may also be recommended.

When conservative measures fail to provide relief or symptoms are severe, doctors may recommend surgery. A discectomy is a procedure to remove the part of the disc that is causing the problem. To access the spinal discs, the surgeon makes an incision, coming in from the front of the spine or through the back. A portion, or the entire disc, is removed to take the pressure off the spinal nerves. To stabilize the spine, doctors usually perform a spinal fusion. A tiny rod and screws are used to hold the top and bottom vertebrae in place. Then a small piece of donor bone or bone fragments are placed in the disc space. The bone will grow and fill in the area, permanently fusing the upper and lower vertebrae.

According to the American Academy of Orthopaedic Surgeons, roughly 325,000 spinal fusions were performed in 2003. Discectomy and spinal fusion can take the pressure off the affected spinal nerves and relieve the symptoms of a herniated cervical disc. But the procedure also permanently eliminates movement in that segment of the spine. If only one disc is affected, only a very small area of the spine is fused and patients don't usually notice any loss of mobility. However, a potential future problem may occur with the discs and vertebrae on either side of the treated section. Some doctors believe spinal fusion puts more pressure on the adjacent segments of the spine and can eventually increase the wear and tear on these areas as well.

Artificial Cervical Discs

An artificial spinal disc is a man-made disc designed to replace a diseased natural disc. In the neck, an artificial disk would eliminate the need for fusion and enable a patient to have more normal motion in the spine. Patients receiving an artificial disc are able to move their neck soon after surgery and have a faster return to normal activity levels. Researchers also believe there is less risk of degeneration in the adjacent segments of the spine.

There are several discs in development for use in the cervical spine. One device in clinical trials is the CerviCore™ Intervertebral Disc. Currently, investigators are undertaking a multi-site study to compare the safety and effectiveness of the CerviCore disc with traditional anterior (approaching from the front) cervical discectomy and fusion. Participants will be randomized to receive one of the two treatments and then followed annually for up to five years. The trial is taking place in the following cities:

Roseville, CA San Diego, CA San Francisco, CA Aventura, FL Clearwater, FL Fort Myers, FL Palm Beach Gardens, FL Chicago, IL Indianapolis, IN Overland Park, KS Scarborough, ME Boston, MA Springfield, MA Southfield, MI St. Louis, MO New York, NY Oklahoma City, OK Pittsburgh, PA Willow Grove, PA Florence, SC Lubbock, TX Southlake, TX Richmond, VA Seattle, WA

For information about the CerviCore™ Cervical Intervertebral Disk Replacement, log onto http://www.stryker.com/spine/products_motionpreservation_cc.html. For information about the study, call (888) 830-PAIN.

AUDIENCE INQUIRY For information about the CerviCore™ Cervical Intervertebral Disk Replacement: http://www.stryker.com/spine/products_motionpreservation_cc.html. For information about the study, call (888) 830-PAIN.

For general information about neck pain or cervical disc problems: American Academy of Orthopaedic SurgeonsNorth American Spine Society