Artificial disc replacement (ADR) is a fairly new treatment for disc problems of the low back or lumbar spine. As with any surgery, problems can occur. Nerves or blood vessels can get damaged during the operation. The implant itself can break or sink down too far into the bone. In a small number of cases, the implant has reportedly moved out of the disc space.
When a total hip or total knee replacement fails, the surgeon tries to revise the implant. Sometimes this means removing a portion of the new joint and replacing it. In some cases the entire joint must be taken out and a new one put in.
ADR is a little different in that it is a fairly new procedure. Long-term results from studies carried out over 10 or 20 years aren't available yet. Indications for revision aren't entirely clear yet. Some surgeons may be more likely to remove the implant and fuse the spine.
As time goes by and more studies are done, ADR revision will become more common. Surgical technique and instruments to do the revision will be developed. The implants will also continue to improve in design and use. Fewer problems will be encountered.