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Doctors Review Nucleus Pulposus Implant

Spinal surgeons are looking to disc replacements as the next possible step in treating chronic pain from disc degeneration. For the past 40 years spinal fusion has been the best medicine had to offer for chronic back pain from disc degeneration. Over half a million adults had spinal fusions in 2005.

But there are many problems with spinal fusion. New treatment methods are needed. Disc implants to replace the aging, worn out inner disc called the nucleus pulposus are being tested now. Doctors from Thomas Jefferson University Hospital in Philadelphia reviewed the history of disc implants. The results are reported in this article.

A major advantage of the disc implant is that it saves motion in the spine. A fusion stops motion at that level and increases the load on nearby segments. The disc implant also keeps the normal disc height, which relieves pressure on the joints and ligaments.

The disc must be able to last over 40 years. It will need to withstand the forces of 2 million strides per year in the average adult. It must be designed to resist fatigue, fracture, or too much swelling. It must stay in place but allow movement of the spine.

Right now nucleus pulposus implants are still under study. The authors say they are "experimental." The big question is whether these implants can function like a human disc. They must be flexible but strong enough to take loads at different rates from different directions. Long-term studies are needed to see how they hold up over the years.

References: Maurice L. Goins, MD, et al. Nucleus Pulposus Replacement: An Emerging Technology. In The Spine Journal. November/December 2005. Vol. 5. No. 6S. Pp. 317S-324S.

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