Artificial Discs: Real Reconstructive Surgery for the Low Back

This is a very exciting time for patients suffering low back pain. Finally, spine surgery is catching up with the rest of joint replacement surgery, which has been performed for over 30 years. Spine surgery is now moving from ‘salvage’ surgery to real reconstructive surgery.

Artificial disc replacement is currently being studied under two Food and Drug Administration (FDA) studies and offers patients new options. In the past, fusion was the only surgical option to treat patients with degenerative disc disease or patients who had had herniated disc surgery in the past. Now we have alternatives, which include artificial disc replacement.

Not a New Concept
The concept of artificial disc replacement is not new. As early as 1987 in Europe the Link® SB Charité III was introduced. To date more than 4,000 patients worldwide have received this artificial disc. In the early 1990’s, the Texas Back Institute began working with the Link® Spine Group, Inc. to help them complete their application for FDA approval.

CHARITÃ Artificial Disc (DePuy Spine, Inc.)
Photograph Courtesy of DePuy Spine, Inc.

The Food and Drug Administration (FDA) has approved the CHARITÃ Artificial Disc (DePuy Spine, Inc. of Raynham, MA) for use in treating pain associated with degenerative disc disease. The device was approved for use at one level in the lumbar spine (from L4-S1) for patients who have had no relief from low back pain after at least six months of non-surgical treatment.

Further biomechanical studies on the Link® SB Charité artificial disc were conducted confirming its efficacy and ability to withstand mechanical wear. In March 2000 the first patient underwent a Charité disc implantation at our Texas Back Institute under the FDA study. Since then, our Institute has continued to be a primary investigator site among 14 investigational centers in the United States.

Phase One
The first phase of the FDA study was completed in December 2001 with 291 patients enrolled. Two-thirds of these patients received the Link® artificial disc. These patients will be closely followed for two years and then the information will be submitted to the FDA. Thus far, the results have been sufficiently encouraging that a second phase of the SB Charité artificial disc study, which will be non-randomized will begin, hopefully, by mid 2002.

PRODISC®: A Type of Artificial Disc
PRODISC® is the second artificial disc currently under investigation through an FDA study. In the early 1990’s, Dr. Thierry Marnay, a French surgeon developed PRODISC®. In October 2001 the first PRODISC® was implanted at the Texas Back Institute, the primary investigator site of approximately 10 investigating sites in the United States.

PRODISC® (Spine Solutions, New York, NY, USA)

The Food and Drug Administration (FDA) has approved the PRODISC®-L Total Disc Replacement (Synthes Spine, Inc. of West Chester, PA). This artificial disc is indicated for use in patients who are skeletally mature, have degenerative disc disease (DDD) at one level in the lumbar spine (from L3-S1), have no more than Grade 1 spondylolisthesis at the involved level, and have had no relief from pain after at least six months of nonsurgical treatment.

To date, approximately 70 patients have undergone implantation of the PRODISC® prosthesis. Good to excellent results with some patients returning to near-normal activities. General availability of this product in the United States is pending results from the FDA study, which are at least two years in the future.

Conclusion
Initial results seem positive, and artificial discs may prove to be a breakthrough for patients suffering chronic low back pain, who did not respond to nonsurgical treatment. We are hopeful that within the next two years we will have the ability to begin implanting artificial discs.