I'm pretty disappointed. I had an artificial disc replacement and I'm no better than I was before. I still have back pain everyday. I'm still using heavy-duty drugs to control the pain. And I can't move any more than before. Am I a rare bird or is this everyone's experience?

You're not rare at all. According to a recent review of data from artificial disc replacement (ADR) research, up to 64 percent of patients with an ADR still suffer from painful symptoms. And this group was taking narcotic medication two years after the implant was put in.

Right now it looks like the complication rate after ADR is no different than with a spinal fusion. In fact there's an increased risk of blood loss because the entire disc is taken out. A large blood vessel goes right through that area. The approach used for most spinal fusions avoids these blood vessels and other important structures.

A good number of implants (17 percent) aren't put in the best location. That increases the patient's risk for implant loosening and loss of motion. Even with good placement, not everyone gets his or her spinal motion back at the level of the implant.

Clearly there are some success stories. More research is needed before we'll really know the final results.