What are artificial discs?
Artificial discs are prosthetics, or disc replacements, made of metal or polymer materials or a combination of both materials and designed to function like natural discs. Most artificial disc designs use metal plates attached to the vertebrae above and below the replacement disc, with a soft bipolymer artificial disc sandwiched between. This design enables the same load transfer capabilities of a natural disc and also allows adequate flexibility.
Performed in Europe since the 1980s, artificial disc replacement received Food and Drug Administration (FDA) approval in the U.S. in 2004. Since then, several artificial discs have been approved by the FDA for use in the lumbar (lower back) and cervical (neck) regions of the spine.
Outside of the U.S., partial disc replacement surgery is also commonly used to repair damaged discs. In partial disc replacements, a special gel is injected into the disc’s fibrous outer shell. The gel then expands to fill the normal disc space. Other procedures use a spiral insert to replace the nucleus pulposus. To date, the FDA has not approved partial disc replacement for patients in the U.S.
Why is artificial disc replacement performed?
Artificial disc replacement procedures are performed to relieve chronic, debilitating pain in the the lower back or neck areas of the spine. In general, patients should meet the same criteria as those used to determine suitability for lumbar or cervical fusion procedures; specifically, patients must have chronic (persistent and long-term) lower back or neck pain and have attempted non-surgical treatments such as pain relievers and physical therapy with little or no improvement. Lumbar disc replacement is usually performed in patients whose primary complaint is low back pain without radiating pain, while cervical replacement is performed in patients who experience pain or weakness radiating into the arms as a major complaint, in addition to neck pain.
Patients undergoing artificial disc replacement also must:
- be good candidates for spine surgery;
- be 18 years of age or older (thought typically not older than 60 years of age);
- not be obese or excessively overweight.
Patients who have had prior surgery to the neck or low back are not good candidates for artificial disc replacement.
How is artificial disc replacement performed?
During the procedure, a small incision is made in the abdomen (belly area) for lumbar disc replacement and the front of the neck for cervical disc replacement. The damaged disc is carefully removed from between the vertebrae, and any remaining cartilage and other debris is removed from the surfaces of the vertebrae to prepare them for the attachment of the artificial disc’s metal plates. The vertebrae are gently moved apart to relieve pressure on the nerves and to make room for the prosthesis. Next, depending on the design of the disc replacement, the metal plates will be moved into position first and fastened to the vertebrae on either side of the disc space with the polyethylene disc core placed between the plates. In other designs, the plates and central core are implanted as a single unit. Once the implant is in place, the position of the artificial disc is evaluated visually and with x-rays before the incision is closed.
What is recovery like?
Artificial disc replacement is a straightforward procedure, and most patients can expect to leave the hospital within a day or two of the procedure with minimal restrictions. Some activities, such as heavy lifting, will be restricted during the initial follow-up period to ensure healing is well under way.
Will insurance cover the procedure?
Because artificial disc replacement is relatively new in the U.S., some insurance companies may not cover the procedure; others may cover the procedure only if specific conditions are met, or they may provide coverage for either cervical disc replacement or lumbar disc replacement, but not both. If you’re considering artificial disc replacement, check with your insurance provider to determine your level of coverage.