Total Disc Replacement
Total disc replacement is a surgical procedure in which the diseased or damaged intervertebral discs of the spinal column are replaced with an artificial disc to restore the normal function and movement of the spine. The discs in your spine are soft cushions that sit between each vertebra, the bones that make up the spinal column.
Traditionally the treatment for damaged discs has been spinal fusion. In spinal fusion surgery, the disc tissue is removed and the empty space is filled with bone between the vertebral bodies. It was thought that by doing so the spine would not move at this segment, and the pain would be significantly reduced. However, there are several problems associated with spine fusion surgery including degeneration of adjacent discs.
Total disc replacement is a relatively new procedure that has developed as an alternative to spinal fusion for patients who have back pain from diseased or damaged intervertebral disc.
Indications and Contraindications
Total disc replacement surgery may be recommended in patients who have back pain from degenerative disc disease, a condition of gradual degeneration of the discs between the vertebrae caused by the natural ageing process, that have not responded to non-surgical treatment options.
Patients with back pain caused from one or two intervertebral discs with no significant facet joint disease are recommended for artificial disc replacement.
Total disc replacement surgery is contraindicated in patients with spinal infection, osteoporosis, allergy or sensitivity to implant materials, spondylolisthesis, spinal tumour, pregnancy, use of steroids for long duration, previous spinal surgery and the morbidly obese.
Diagnosis
Your doctor will take a medical history and perform a physical examination. Certain tests such as magnetic resonance imaging (MRI), computed tomography (CT or CAT scan), and X-rays may be recommended to determine the source of your back pain. Your physician may also perform a discography, a procedure to determine which disc in the spine is causing pain. During a discography procedure, a special dye is injected into the disc, then X-rays and a CT scan are taken to verify which disc is causing pain.
Disc design
An artificial disc is a device that is inserted into the disc space between the vertebrae to simulate the movement of a normal disc.
Artificial discs are made of metal or plastic or a combination of metal and plastic. Medical grade plastic (polyethylene) and medical grade cobalt, chromium or titanium alloy are the materials used for disc design.
Procedure
The aim of total disc replacement is to replace the damaged painful disc, while restoring motion to the spine.
Total disc replacement surgery is performed under general anaesthesia. During the surgery, you will be positioned on your back on an operating table. Your surgeon will make an incision near your belly button. Through this approach the organs and the blood vessels are carefully moved aside to gain access to the spine. An X-ray is then taken to see a well-defined image of the disc to be replaced. The surgeon will then remove the diseased disc and the disc space is prepared to receive your new artificial disk. The metal endplates of the implant are inserted and tapped into the correct position. Finally, the sliding polyethylene core is placed between the endplates. As the vertebrae are returned to normal posture, the pressure of the spinal column places the endplates into the vertebral bones and secures the sliding core in position. After the procedure, another X-ray is taken to verify the position and fit of the new disc.
Advantages
The advantages of total disc replacement surgery over traditional fusion surgery includes:
- Early return to activities
- Allows a greater range of motion
- Decreased stress on the adjacent discs
- Reduced risk of degenerative changes to the discs above and below the fused area
Post-operative Care
After disc replacement surgery the hospital stay is usually 2 to 4 days depending on your progress. You should be able to walk and stand by the first day after surgery. A brace or corset may be prescribed for support. Basic exercises such as walking and stretching are usually initiated during the first several weeks after surgery. However, hyperextension activities should be avoided.
Risks and Complications
The potential complications associated with total disc replacement surgery include:
- Infection
- Blood vessel injury
- Dislocation of the device
- Wear of the device materials
- Nerve damage
- Continued pain
- Chances of developing new pain
- Sexual problems
- Damage to adjacent structures