New Hope for Low Back Pain
By Thomas J. McGivney, M.D.

There are countless causes of low back pain, many of which continue to perplex spinal surgeons and are not well defined or understood. One known and common cause is degenerative disc disease (DDD). As an individual ages, there is a normal physiologic loss of water content in all tissues, especially in the discs between the vertebrae in the lumbar spine. In a significant number of people this loss of hydration occurs earlier in life and progresses more rapidly that usual resulting in the development of disc collapse and narrowing, often followed by instability and pain. Chronic and often severe low back pain may develop. Fortunately, many patients can be treated without surgery with aggressive physiotherapy, medications, and/or spinal injections. A subset of patients, however, continues to experience life altering, debilitating back pain despite adequate conservative care and for those patients surgery becomes an alternative.

For nearly 50 years, the mainstay of surgical treatment of DDD was a lumbar fusion. Lumbar fusion is the process of stabilizing the degenerative segments of the spine by fusing together the vertebrae at the effected levels. By causing the bones to grow solidly together, all motion at the affected discs, and subsequently all stress on those discs, is eliminated, thus hopefully eliminating the cause of pain. Fortunately, the accuracy of diagnosis of DDD has improved through the years so that the segments to be fused can be determined with greater certainty. Additionally, the surgical techniques involved have advanced dramatically so that prolonged use of body casts postoperatively has largely been eliminated and the success rate of fusions has increased significantly. Unfortunately, lumbar fusion may lead to increased stress and increased motion at the levels of the spine wither above or below the fused or stabilized area, thus accelerating degeneration of the discs at the adjacent levels, which can result in the development of pain from those levels requiring treatment and possibly necessitating further surgery to extend the fusion. Studies have estimated that the rate of re-operation for treatment of degenerative disc disease at levels adjacent to previously successfully fused levels is approximately 20%.

For many years clinical research has been underway to develop surgical treatments to solve the problem of degenerative disc disease without fusing the diseased segments. Today, an alternative to fusion is now available that restores the disc height and motion be replacing the disc with a prosthetic implant or mechanical disc. The first lumbar disc replacement was actually performed around 1950. In 1982, the first commercially available artificial disc was developed by Drs. Shnellnack and Buttner-Janz and actually implanted in 49 patients at the Charite hospital in East Germany . Further refinements by Dr. Waldemar Link resulted in the introduction of the third generation of the CHARITE artificial disc in 1987, and surgeons in Europe have been using this prosthesis for the last 15 years. Within the last 5 years clinical studies involving the CHARITE artificial disc as well as several other lumbar disc replacement devices have been undertaken in the United States . Recently, one artificial disc, the CHARITE, has been granted FDA approval for the treatment of single level degenerative disc disease. In the coming years, more companies will be offering similar devices pending appropriate study and government approval.

Successful disc replacement surgery is dependent of a great many factors including proper patient selection. Only patients whose degenerative disc disease is limited to a single disc are candidates for the procedure, and even those patients must have failed to gain satisfactory relief of their symptoms with non-surgical treatment. In addition to rigorous patient selection, meticulous surgical technique is necessary for a successful outcome. Accordingly, many surgeons are now actively training to learn the techniques of disc arthroplasty (replacement) thus providing their patients with access to another option in the surgical management of low back pain.

While disc replacement surgery is a new and potentially beneficial treatment for selected patients, many questions and concerns need to be addressed including the long-term results and possible complications from this procedure. Further studies are currently underway in the hope of answering these and many more questions that will undoubtedly arise. But today the future is brighter for patients which chronic low back pain caused by degenerative disc disease thanks to the CHARITE disc.

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