OrthoNeuroSpine & Pain Institute

Cervical Disc Replacement Surgery

In the backbone, spongy pads of tissue called discs lie between the small bones (called vertebrae). They act like cushions, and have a tough outer ring and a soft jelly-like inside. Acute disc herniation, which is more commonly called a slipped disc, happens when the tough outer ring of a disc tears. The jelly-like middle bulges out through the tear and this may press on nearby nerves, causing pain and weakness in the muscles.

In cervical spondylosis, the cartilage and bones in the neck become abnormally worn, and the discs between the small bones start to disintegrate. Bony growths may develop on the bones. These changes can cause pressure on nearby nerves and this can cause pain in the neck and arm, weakness, and changes in sensation.

Cervical artificial disc replacement surgery is a joint replacement procedure that involves inserting an artificial disc between the vertebrae to replace a natural spinal disc after it has been removed.

A cervical artificial disc is a prosthetic device designed to maintain motion in the treated vertebral segment. A cervical artificial disc essentially functions like a joint, allowing for flexion, extension, side bending and rotation. Some newer discs are compressible, and actually function like shock-absorbers, as do natural discs.

One problem about artificial discs of all types, however, is that we can only guess at how they will behave in the spine afters years of use. We try to make an educated guess from millions of cycles of bench-testing in the laboratory, but the only real proof will emerge over the next 20 years or so.

An exciting new technology available for the neck is disc replacement, or cervical disc arthroplasty. This procedure represents a huge step in the preservation of the patient’s normal function and activity to correct the problems associated with herniated or degenerated discs. For decades, the anterior cervical discectomy and fusion procedure (ACDF) was the standard surgical treatment for disc conditions that cause neck pain and arm pain, weakness, numbness or tingling. About 6 years ago, the FDA approved cervical disc arthroplasty for the treatment of these conditions after several studies confirmed the safety and efficacy of this procedure.

So, why is disc arthroplasty preferred to ACDF surgery? The major benefit of the disc arthroplasty is the preservation of MOTION at the surgically treated disc level. Specifically, NO FUSION is performed. Instead, a bearing-type device is used to replace the disc and this allows natural neck movements immediately following surgery. Also, the relief of arm symptoms is usually dramatic and most persons return to normal activity within several weeks.

Why Might I Need This Procedure?

The intervertebral discs of the cervical spine are very important for the normal mobility and function of your neck. When healthy, they act as "cushions" for the individual bones of the spine, or vertebrae. Each disc is made up of two parts

• The nucleus pulposus - the soft, gel-like center of the disc
• The annulus fibrosis - strong, fibrous outer ring that surrounds and supports the nucleus pulposus

Over time, discs can become dried out, deflated or otherwise damaged, due to age, genetics and everyday wear-and-tear. When this happens, the nucleus pulposus may push through the annulus fibrosis. Disc degeneration also may result in boney spurs, also called osteophytes. If disc or bone material pushes into or impinges on a nearby nerve root and/or the spinal cord, it may result in pain, numbness, weakness, muscle spasms or loss of coordination, both at the site of the damage and elsewhere in the body, since most the nerves to the rest of the body (e.g., arms, chest, abdomen and legs) pass from the brain through the neck. Similar symptoms, however, may occur suddenly if the disc nucleus dislodges acutely and causes nerve root compression, a condition referred to as a herniated disc.

The goal of cervical artificial disc surgery is to remove all or part of a damaged cervical disc (discectomy), relieve pressure on the nerves and/or spinal cord (decompression) and to preserve spinal alignment, whilst restoring mobility.

Not everyone with symptoms of disc degeneration in the neck is suitable for implantation of an artificial disc. In fact, more people need an anterior interbody fusion than are suitable for an artificial disc.

Cervical artificial disc replacement surgery may be an appropriate treatment option for you if:

• You have been diagnosed with cervical radiculopathy, myelopathy or both with the presence of disc herniation and/or bone spurs
• Your disc has not deflated to such an extent that it has lost more than 50% of its original height
• The facets joints at the back of the spine at that level do not show degenerative changes (wear and tear)
• Your symptoms did not improve after conservative treatment measures, which usually include: abandoning harmful neck exercises and manipulations, walking for exercise, avoidance of soft chairs and watching TV lying down, and strict attendance to erect sitting
• You require treatment at only one cervical level
• You are at least 18 years of age with skeletal maturity
• You are not pregnant

How Is Cervical Artificial Disc Replacement Surgery Performed?

Through a small incision made near the front of your neck (a surgical approach called the anterior approach) your surgeon will:

• Gently pull aside the soft tissues - skin, fat and muscle - as well as the trachea (windpipe) and oesophagus (the tube down which you swallow) to access the cervical spine
• Remove the disc and bone material from around the neural structures to relieve the pressure on them
• Insert and secure the artificial disc into the intervertebral space, using specialized instruments
• Ease the soft tissues of the neck and other structures back into place and
• Close the incision