What is a Total Disc Replacement (TDR)
To understand what an artificial disc does, it is important to know what a real disc does in the spine.
A disc is a fibrocartilaginous structure that sits between adjacent vertebral bodies. In the spine, a human has a total of 23 disc which includes 6 cervical (neck) discs, 12 thoracic (middle back discs), and 5 lumbar (low back) discs.
The discs in the spine have three primary functions:
- They act as a shock absorber
- The act as ligaments that hold the vertebrae of the spine together
- The are cartilaginous joints that allow for slight mobility in the spine
When discs become weakened (degenerate) or are injured (herniated or bulging) the bone on bone shock absorbing action is affected causing serious back or neck pain. When disc bulge or herniate, they impinge on the spinal canal or push on nerves causing pain, weakness and serious injury.
Minor repairs to a disc include a microdiscectomy procedure that allows the surgeon to remove the portion of a disc that is bulging into a the spinal cord or pushing on a nerve.
When the disc has degenerated or become too damaged to fix with a microdiscectomy, the surgeon may choose to perform a fusion or an artificial disc replacement procedure.
In a cervical fusion, the disc is completely removed and replaced with a strong plastic or titanium spacer that allows bone to grow through the device that will fuse to the surround vertebral bodies. This creates a rigid column of bone in place of where the disc was removed.
In artificial disc replacement surgery the patient’s disc is surgically removed (the same as in a fusion surgery), however an artificial disc is used to replace the original disc. The artificial disc is usually a three piece device that consists of two surgical titanium end plate parts that rest on the superior (top) and inferior (bottom) end plates of the vertebral bodies affixed with spikes or a keel design, plus a rounded poly or ceramic device that is sandwiched in the center. The centered device gives the artificial disc the ability to achieve motion similar to that of a human’s real disc.
What are the advantages of an Artificial Disc over a Fusion?
Artificial disc replacement has several advantages of a fusion.
It preserves mobility. When a person has a fusion surgery the column of bone negates the ability to have mobility at that level of the person’s spine.
When a person has artificial disc surgery, they are not required to wear a collar or brace after surgery. When a patient has a fusion surgery, it is important that they wear a brace for several weeks in order to prevent a non-union of the bone. This requires additional surgery.
Artificial disc do not have to heal so there are much less complications after surgery.
To learn more about artificial disc surgery and to see if you are a candidate, call and make an appointment with Jason E. Garber, MD, FANNS