Cervical Disc Replacement

Please note that since late 2006, following a ruling from Medicare Australia, cervical disc replacement is no longer funded by Medicare or by private insurers.  It may be some time before this decision is reviewed.  It means that private insurance will no longer cover the costs of the procedure or the cost of the device.

What is a cervical disc prolapse?

A cervical disc prolapse is a protrusion of one of the discs in the neck. This protrusion frequently causes pressure on one of the nerves to the arm ("a pinched nerve"). On occasions, a cervical disc prolapse may press against the spinal cord, causing symptoms potentially much more serious than those of a single pinched nerve.

Prolapse of a disc is often referred to as a protruding disc, a herniated disc, a slipped disc, a bulging disc, a ruptured disc or even a collapsed disc. These terms usually refer to the same process.

Cervical disc prolapse is often associated with overgrowth of bone, the latter occurring as part of a degenerative process known as spondylosis. Spondylosis is extremely common. Nearly everyone over 35 years of age develops some degree of spondylosis. Spondylosis can make a disc prolapse more likely to cause pressure on the nervous system, resulting in neurological symptoms. In some cases, pressure on the nerve or spinal cord is caused by a spur of excess bone (an osteophyte), rather than a prolapse of the disc.

Why should the disc prolapse?

A normal healthy disc does not undergo prolapse, unless a severe accident occurs. Most cases occur as "the straw that breaks the camel’s back". There has been gradual deterioration in the structure of the disc going on behind the scenes over many years, causing only minor or intermittent neck pain. Eventually, the disc prolapse occurs in an already weakened disc, and the severe symptoms develop. Often some fairly ordinary activity seems to have caused the prolapse, such as a game of tennis or an episode of gardening, but in reality this is only the "last straw". Not infrequently, people develop the symptoms of a cervical disc prolapse without being aware of any specific injury or event.

What are the symptoms of a cervical disc prolapse or osteophyte?

The most important symptoms are neurological symptoms, meaning those symptoms due to pressure on the nerve(s) in the neck. These symptoms are usually felt in one arm. Pain is often severe, especially in the shoulder and upper arm, and may shoot down the arm to the hand or fingers. Tingling or numbness in one or more of the fingers is very common. Loss of strength is also common, particularly with strength at the elbow. The exact pattern of symptoms depends on which particular nerve is involved.

If the disc prolapse causes pressure on the spinal cord, then symptoms in all four limbs can occur. Rather than causing pain, pressure on the spinal cord causes tingling in the arms or legs (or both), as well as causing impairment of walking due to unsteadiness of gait. Control over bladder and bowel function can also be impaired. Neck pain is a common part of the picture, but is usually not due to the disc prolapse itself. So too is headache a common complaint. However these symptoms are not usually considered to be caused by pressure on any one particular nerve.

Why do I need surgery?

The main reason for recommending surgery is to relieve the pain that radiates down the arm. If there is evidence of nerve damage causing weakness in the arm, surgery may also be advisable even if the pain is not severe. It is not customary to perform surgery for the relief of neck pain.

The Place of Cervical Disc Replacement in 2006

The traditional operation for your condition has for many years been cervical fusion. In this procedure, the disc or bone spur causing pressure on the spinal nerve or the spinal cord is removed, and the gap created is filled with either a bone graft or with an artificial spacer. The intention of the operation is to remove pressure on the nerve and to eliminate movement at that point in the neck by fusion.

Cervical Disc Replacement is a new procedure which closely resembles the traditional cervical fusion operation but in which movement is preserved. That part of the operation in which the disc or bone spur causing pressure on the spinal nerve or the spinal cord is removed does not differ in any way from the cervical fusion procedure. What does differ, however, is that instead of fusing the spine, an artificial disc is inserted which enables movement to continue in a fashion which is very similar to the movement of a normal cervical disc.

It has now been shown that in the years after a cervical fusion, disc problems above or below the level of surgery can occur because of extra strain on those discs caused by the stiffening of the spine at the level of the fusion. Cervical Disc Replacement has emerged as a means of addressing this possibility.

The advantages of cervical fusion include its reliability, predictability and long-term track record. Its main disadvantage is its association with disc problems later in life. The advantage of Cervical Disc Replacement is the preservation of movement and, hopefully, fewer problems at other levels in the neck later in life. The principal disadvantage is that the procedure is new (in Australia and the United States, but not in Europe) and the long-term effects are still unknown.

You should be aware the Cervical Disc Replacement is new to Australia and remains controversial. Many experienced spinal surgeons and neurosurgeons are sceptical or even opposed to its use at the present time. You may wish to obtain a second opinion before surgery. However, with more than 6000 cases already performed in Europe and elsewhere it is not an experimental operation and the various devices available in Australia at present have been approved by the respective Government authorities.

What is actually done in the operation?

An incision over the front of the neck is made just to the right side, often running in a skin crease. It usually heals to a fine line quite quickly. The wound is on the right even if the symptoms are on the left. The surgery is performed between the throat and the blood vessels of the neck. The correct level is identified with an x-ray taken during the surgery, then the procedure is performed.

The details vary depending on the particular problem, but generally the disc is completely removed, along with some bone from the vertebrae on either side of the disc. This is rather like removing the mortar between two bricks, and then trimming a little of the brick on either side of the gap. This gives space for the surgeon to remove the offending particle of prolapsed disc or to trim away the osteophyte as the case may be. In either case the object of the exercise is to relieve pressure on the nerve or the spinal cord, depending on the symptoms and the results of preoperative investigations.

Once the decompression is complete, the gap left by removing the disc is filled (implanted) with the disc replacement device (also known as a "prosthesis"). The device and the final appearance on an x-ray look like this:

What about risks and complications?

The risk of serious complications is low, and the risk of death is remote. The risk of less serious complications is somewhat higher. Complications are of two types, general and specific. General complications are those that can occur with any operation, while specific complications are those relating to surgery on the cervical spine. General complications are in general related to age and to underlying disease. A person aged 75 years with diabetes and a history of heart attack is at greater risk of complications than a 40 year old with perfect health.

General complications include stroke, heart attack, bleeding in the wound postoperatively, blood clots in the legs (which can travel to the lungs or heart) and infection. Specific complications include damage to one or more of the nerves travelling through the spinal canal. This could cause permanent numbness or weakness in the limbs, and could affect control of bladder or bowel. Bruising or damage to the nerve controlling the voice can occur and can mean a permanent huskiness.

It is also possible for the artificial disc device to become dislodged and if this occurs further surgery would be required.

Serious complications are rare. You should not be unduly concerned with the risk of serious complications. However, failure of the surgery to meet expectations (without anything going wrong) is a more likely possibility. This means that despite the best efforts of the patient and the surgeon, the symptoms do not respond to surgery as one would normally expect. This is very disappointing but does occur in up to 10 percent of cases. Reasons are not always obvious.

How long will I be in hospital?

The usual hospital stay is 2-4 days.

What can I expect after the operation?

There will be some pain in the area of the wound itself, as well as a sore throat, possibly with some slight difficulty in swallowing for a day or two. Normally, no collar is required. You will be able to get up, sit out and move around the day after the operation.

Will I need physiotherapy?

Most patients are seen by a physiotherapist during their stay in hospital, mainly to ensure that the simple movements like getting out of bed are done correctly. There is usually no physiotherapy during the first six weeks or so after discharge from hospital, and only a minority of people will need on-going physiotherapy after that.

What about when I get home?

The most important aspect of the first six weeks after surgery is rest. The wound needs time to heal, internally as well as externally. This takes a few weeks. The best plan is to schedule two good walks of about 15 minutes each per day, and to spend most of the remaining time resting. If your occupation is sedentary, then a return to work in 2 to 4 weeks is likely. If your work is manual, then a longer time off work can be expected. Your first review appointment will be about six weeks after the operation.

It is hard to predict how long it will take for recovery to be completed. In most cases, the symptoms due to the disc prolapse will have eased within six weeks, but you should not regard this as a deadline - some people take longer than this to get benefit from surgery.

If your neck problem is the result of an injury at work, then you may need a rehabilitation program. The type of program needed will depend on the nature of your work, the size of the workplace, the duration of symptoms and on the details of the surgery itself. Rehabilitation may involve input from a number of sources, such as your family doctor, your employer or rehabilitation service providers, whether they be as an inpatient or outpatient.

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