It’s very successful because it still maintains motion at the individual disc level. So if you take part of the disc out or the entire disc out, you can stabilize the spine at that level with an implant that actually moves, maintaining motion. This means the patient benefits from maintained motion and also experiences a decrease in the amount of force transferred to the next level.
By decreasing the amount of force to the next level, it helps protect the other parts of the spine that haven’t been injured, reducing the chance of degeneration or other problems later. Several FDA trials have compared fusion to disc replacement over time for specific indications in both the cervical and lumbar spine. In most studies, there was equivalence at two years. However, with further follow-up at 5 and 10 years, the disc replacement patients uniformly did much better than the fusion patients, thanks to the lack of destruction of the other levels later.
