The first artificial disc replacement (ADR) was invented by a French doctor in the 1980s. It wasn't until the late 1990s that the device was widely used in humans. In Europe over 5,000 ADRs have been implanted.
Use of the ADR has been a little slower in the United States. The first cases were done in 2001. Reports of results are starting to trickle in. There are a limited number of surgeons and centers where this type of surgery is done in the United States.
There have been cases of patients going to Europe to have the disc implanted. So far only one report of failure has been published. An American had two disc replacements done in Europe. One ADR slipped forward and cut off the circulation to his leg. By that time he was back in the U.S. A U.S. surgeon found the problem and corrected it by removing the implanted device and fusing the spine.
Wherever you decide to go (U.S. or Europe) ask about the number of cases done and the incidence of any problems or complications. These are the early years of a new treatment. Caution is always advised until the device and surgical technique have been perfected.