Narrator: This is Science Today. Orthopedic surgeons at the University of California, San Francisco are joining 13 other centers in a four-year study to determine the safety and effectiveness of a European-designed implant called the Prosdisc that may replace damaged lower back discs. Dr. David Bradford of UCSF says the Prosdisc shows lot of promise.

Bradford: Over 300 to 400 cases now have been done worldwide and over 100 cases have been done in North America and the data looks very good - the early results. Nonetheless, the FDA wants to see controlled studies comparing this with standard fusion to see if truly this result is better than what you might see with a fusion.

Narrator: The ball-and-socket design of Prosdisc allows normal functioning and structure of the spine.

Bradford: We've done this procedure already here at UCSF. We feel that the results are most likely to show that this would be approved as a stand-alone device.

Narrator: For Science Today, I'm Larissa Branin.