When I take my car in and get a part replaced, the new part usually has some kind of guarantee. When I go in next week for a disc replacement in my spine, are there any guarantees for the implant?

Good question. The medical world doesn't usually offer guarantees of any kind. In fact before any operation the patient gets a list of all the things that can go wrong and has to sign it to show understanding and agreement.

In 1999 the Texas Health Research Institute reported disc implants last 10- to 12-years in about 63 percent of the disc replacement patients. The problem is knowing which patients will fall into that group and whether you'll be one of them.

Studies show patient selection for this operation is important. Younger patients with only one disc level involved have the best result. There has to be enough disc space left to let the doctor insert the implant in place. There's a tendency to stretch the bones too far apart when the disc space is too narrow. This can cause chronic pain from nerve damage.

Success is measured in different ways by different patients. Some say pain relief is all that's needed. Others expect pain relief and return to full function. Return to work is a big goal for many patients. Guaranteeing implant success just isn't possible at this time. As implants improve in design and function, we can expect to see better results.