A new approach to surgical treatment of degenerative disc disease has reached the point of clinical trials in the United States. Just as we now very successfully replace worn out hip and knee joints with metallic and plastic artificial joint constructs, the new lumbar spine technique entails replacing the damaged, painful, inadequate intervertebral disc with a titianium/polyethylene prosthesis which is designed to restore the normal disc function back to the vertebral motion segment. The loss of height from degeneration and the deficiency in stabilizing effect of the damaged disc is corrected without destroying the function of the joint as occurs in surgical fusion which is the current standard of surgical care. This technique reestablishes the pain free motion of the damaged spinal segment.

Although fusion is often a successful treatment of this disease process it entails definite drawbacks. In some cases there are multiple damaged discs, so fusing any of them confers more stress on any remaining ones.In the x-ray here one can see instability and degeneration of the joints next to a two level fusion. These remaining discs then have to "carry the load" of the fused discs as well as their own. In the situation where many are painfully damaged and would have to be fused, fusion doesn't solve the problem of pain and disability because the remaining unfused joints sooner or later become overloaded and more problematic. So a technique that solves this common dilemma is most welcome. The Prodisc does just that! It allows the diseased disc to keep on moving and doing its share of the load function. Studies have shown that the joints next to fusions can frequently deteriorate over the years and require more surgical treatment. Because the fusion procedure requires such extensive surgery and a waiting period for the bone to actually grow together the recovery period is typically 4 to 9 months. On the other hand the recovery for the Prodisc procedure is only a few weeks. The Prodisc can be performed by endoscopic approaches in the hands of experienced surgeons. In order to achieve a high level of fusion consolidation abdominal and back incisions are frequently utilized together in lumbar fusion surgery.

Shown below on left and center, the Prodisc is a three-piece construct. Two pieces are titanium designed to encourage the vertebral body bone to grow into the titanium endplates and a central ultra high molecular weight polyethylene with an extremely low coefficient of friction. This allows normal spine motion. It is implanted through small abdominal incision seen at surgery on the right.

Dr. Marnay of France invented the Prodisc. In the early 1990's, he began a long-term follow-up study to establish the usefulness of this new approach. The device was implanted in 64 patients and 58 of 61 who were available for follow up were evaluated 7 to 11 years after the procedure. Using extensive standardized outcome measurement tools the results were obtained:

Ninety-five percent of patients were followed which is a high level for such a long term surgical outcomes study. About a third of patients had had two levels operated and 2/3 one level treated. All cases had continued function of the disc replacement. Even with CT scanning in most of the cases no evidence of subsidence (settling of the prosthesis into the vertebra) or migration of the disc replacement were found. No cases required revision or removal. Statistically significant reduction in the patients back and leg pain were found to the p>.0001 level. The satisfaction rate of the patients was 93%. Results were as good with two levels as with one. No device related problems or complications could be identified. The results of this study in Europe were so compelling and so meticulously gathered that the United states FDA as accepted the data as a Pilot study showing the device is safe and has allowed multi-centered pivotal trials comparing the technique to fusion to begin in the United States. Approximately ten surgical spine centers across the country will be conducting the randomized study including the St. Mary's spine center in San Francisco, the Texas Back Institute in Fort Worth, and the Hospital for Special Surgery in New York. Study centers are expected to be enrolling patients before the end of the year. In the mean time a controlled release of the refined version of the Prodisc, Prodisc II has been ongoing in Europe with Dr. Marnay the inventor in France, and two German Surgeons who Dr. Marnay has trained performing cases for the first year and a subsequent ten more surgeons trained this year. These European surgeons have performed 120 cases to date. Dr. Marnay or one of the two German surgeons has or will have trained all of the investigators in the United States.