Degenerative disc disease is the main reason total disc replacements (TDRs) were developed. Before that, spinal fusion was a patient’s only choice. With the TDR, the patient can experience rapid pain relief and faster recovery compared to spinal fusion.
Not only that, but motion is preserved. Patients are happier with the outcomes and complication rates are lower with TDR compared with spinal fusion.
Deciding who is a good candidate for TDR and the best time to do it are still under considerable study. Long-term results are just becoming available. It looks like there may be some problems with disc and joint degeneration at the level above the implant.
Until these kinds of problems are ironed out, TDR will probably remain at a single level for now. Deciding which level to replace is also under debate. Many surgeons use provocative discography to find the most painful level. This test is somewhat painful itself so it is not used routinely. However, it is fairly accurate in identifying the most problematic area.
Other imaging studies such as CT scans and MRIs may be used along with the patient’s report of symptoms to identify the best disc to replace.