Why a mechanical disc?

Low back pain secondary to degenerative disc disease is an overwhelming and growing problem in the United States and Western countries. Most degenerative disc disease can be treated nonoperatively. There are, however, substantial numbers of patients who have not benefited from exhaustive nonoperative treatments and subsequently seek surgical solutions to their incapacitating back pain. Lumbar fusion for back pain and/or leg pain associated with degenerative disc disease is considered the gold standard by which other treatments are judged. A challenge to spinal fusion for degenerative disc disease is now being offered in the form of the artificial disc. The implantation of an artificial lumbar disc allows for maintenance or restoration of physiologic movement at affected segments. A major long-term complication of spinal fusion is degeneration of a disc adjacent to the fused segments. Theoretically, the maintenance of motion could minimize development of adjacent disc degeneration as seen with spinal fusion. It is interesting to note that fusion of the hip or knee is not considered a primary procedure, but fusion is a primary procedure for the lumbar spine. Four artificial lumbar discs are discussed in this article. Early results are promising in terms of clinical results and movement, but long-term follow-up clinical trials must be done in order to gain an accurate comparison with spinal fusion. Trials are currently ongoing. The clinical results up to now and the potential for maintaining lumbar mobility throughout life warrant continuation of this surgical procedure.