Total disc replacement (TDR) continues to be a heated topic. But after 15 years, there’s still no evidence that disc replacement is reliable over a long period of time. These authors report that TDR should be considered an experimental operation until proven safe.
There are two parts to the natural disc: the central part called the nucleus and the outer layer, the annulus. Both parts are replaced in TDR. An implant of this type is referred to as an artificial joint or disc arthroplasty.
There are still many questions about the use of these devices. For example:
The authors of this report reviewed all studies available on this subject. They found that the short-term results of TDR are similar to spine fusion. Long-term results aren’t reported. Loosening of the TDR device hasn’t been studied yet.
After TDR, spine motion is often lost, resulting in fusion between the two vertebral bones after a short time. This defeats the purpose of using an implant instead of just doing a spinal fusion. Wear and tear on nearby spinal levels hasn’t been followed up past two years. The implant can be taken out if it fails. When this occurs, a fusion is needed after all.
According to the authors, research is incomplete on TDR. Even though the devices have been around more than 10 years, the results and possible problems are still not clear. For now, total disc replacement doesn’t seem to be better than fusion.