|
These are both very good questions, and ones you will want to bring up with the surgeon at the next pre-op visit. Artificial disc replacements do come in different sizes, shapes, and styles. They can be made of metal, ceramic, or plastic. Cobalt chromium alloy is a safe material that has been used for many years in replacement joints for the hip and knee.
A plastic (polyethylene) core fits in between the two metal endplates. The core acts as a spacer. It is shaped so that the endplates pivot in a way that imitates normal motion of the two vertebrae. There are small prongs or teeth on one side of each endplate. The teeth help anchor the endplate to the surface of the vertebral body.
Another way of anchoring the artificial disc replacement is the central keel or fin design you described. The implant is secured to the vertebral end plates by a thin, upright piece of metal that looks like the rudder on a boat or a shark’s fin.
The surgeon uses a special method of X-ray imaging called fluoroscopy to guide the implant into place. Before the device is installed, the old, damaged disc is removed. Any bone spurs in the area are removed and the bone is smoothed out.
A special slot is chiseled out for the keel. The surgeon slides the implant into place making sure the keel goes in the slot properly. Once in place, the implant can't rotate or slip sideways out of the slot.
During this part of the operation, the surgeon also tries different sizes of implants to find the right one for each patient. Some companies have as many as 12 different sizes to choose from. It's important to avoid an implant that is too large or too small. In rare cases, even the smallest implant may be too large for the patient. If the results are not satisfactory, the implant can be removed and the spine fused.
|
