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


How Long Will It Take Me To Recover?

The amount of time that you have to stay in the hospital will depend on this treatment plan. You typically will be up and walking in the hospital by the end of the first or second day after the surgery. You may return to work in 3-6 weeks, depending on how well your body is healing and the type of work/activity level you plan to return to.

Every patient is different, however, and Prof. Brazenor will determine the appropriate recovery protocol for you. Please note that much of this advice is for your safety, and thus it is important that you follow it to the letter.

Are There Any Potential Risks Or Complications?

Any surgery and anaesthesia can result in injury or even, rarely, death. One only has to read the newspaper to confirm that fact. Complications such as infection, nerve damage, blood clots, blood loss and bowel and bladder problems, along with complications associated with anaesthesia, are some of the potential risks of spinal surgery. A potential risk inherent to spinal fusion is failure of the vertebral bone and graft to properly fuse, a condition that may require additional surgery.

The sorts of complications which can occur with surgery to cervical spine include the following:

  • Implant failure
  • Infections
  • Neck and/or arm pain
  • Difficulty swallowing
  • Voice Hoarseness
  • Nerve or spinal cord injury, possibly causing impairment or paralysis
  • Development or progression of disease at other cervical levels
  • Bleeding or collection of clotted blood (hematoma)
  • Reactions to from anaesthesia

 

What is cervical disc replacement surgery?

Worn or herniated discs can cause pressure on the spinal nerves, rubbing of the vertebras resulting in pain in the neck, back and upper limbs. The standard operation involves removing the part of the disc or discs that is bulging out or pressing on the nerves and replacing the void with a prosthetic disc. The prosthetic disc is designed to restore disc space and height, to restore flexibility and to minimalise the risk of disc degeneration.

Why is this surgery suitable for me?

Surgery is an option for slipped discs and cervical spondylosis if:

  • painkillers, rest, exercises and injections don’t help
  • there is a likelihood of serious complications involving the nerves if left untreated
  • when the pain in the neck, upper back and arms is having a profound effect on your quality of life

The aim of the procedure is to reduce the pain in the neck, back and arms.

How is it performed?

The procedure is performed under general anaesthetic. The standard surgical procedure for a disc replacement is an anterior (from the front) approach to the cervical spine. The affected disc is completely removed including any impinging disc fragments or osteophytes (bone spurs). The disc space is propped up to its previously normal disc height to help relieve pressure on the nerves. This is important because when a disc becomes worn out, it will typically shrink in its height, which can also contribute to the pinching on the nerves in the neck. At this point, the artificial disc device is implanted into the prepared disc space. X-ray images will be taken to confirm the disc has been positioned correctly. You will need a minimum two night stay in Hospital. Following surgery, you will need to undergo a physiotherapy-based rehabilitation program.

Some important considerations

The procedure is a more recent development and long term effectiveness of a prosthetic disc has not been studied, however short term reports have provided good results.

Surgery seems to get people better quicker but has some risks associated with it.

Surgery has less risk, and is safer, on fit and healthy patients. It is common sense to take responsibility as a patient to reduce the risks whenever possible. Simple measures such as stopping smoking, losing weight and improving aerobic fitness all help.

If you have had pressure on the nerve for a long time or the nerve has become damaged by the pressure, you may not get a complete recovery of the nerve function. This means that you might always have some numbness in parts of the arm or legs, or weakness of some of the muscles after surgery.

Associated risks

  • infection of your wound after surgery, which is not usually serious and can be treated with antibiotics (deeper spinal infection is more serious but very rare) (occurs in 1-3% of cases)
  • damage to nerves and blood vessels, which occurs in rare cases (1%)
  • paralysis, which could occur if there is bleeding into the spinal canal after surgery or the blood supply of spinal nerves is damaged (<1%)
  • difficulty swallowing, caused by a temporary swelling of the neck (10%)
  • hoarse voice, if the nerve to the voice box is injured you may have a temporary speech problems, in rarer cases when the nerve is cut, the problems may be ongoing (10-15%)
  • implant failure, if the body rejects the implant, a further operation may be required. Alternatively if the implant moves and press on the nerves, the initial symptoms may return (5%)
  • rare complications associated with general anaesthetic, such as heart attack, blood clot in the lung or an allergic reaction