Lumbar artificial disc replacement, also called total disc replacement, is indicated for the treatment of painful lumbar discs. The facet joints, which are paired and in the back of the spine at each disc level, must have little or no arthritic changes in order for the disc to be treated with artificial disc replacement, to minimize the risk of potential postoperative pain due to continued painful facet joint motion.
Currently there are several artificial disc implants that are FDA approved for use in the US. There are many factors that would make a patient ineligible for a lumbar artificial disc surgery. For example, patients must have good bone quality (no severe osteoporosis) to be candidates for total disc replacement, and cannot have pre-existing spinal instability in the form of subluxation (e.g. spondylolisthesis) or abnormal curvature of the spine (e.g. scoliosis).
How is Lumbar Artificial Disc Replacement Performed?
Currently, artificial disc implants are designed to be placed into the disc space from the front and center position. To get there, the surgical approach is performed anteriorly (from the front), reaching the spine and disc working around the abdominal contents (retroperitoneal) from an incision at or near the front of the abdomen.spine surgeon during anterior spinal procedures such as total disc replacement.
Anterior interbody spinal fusions are commonly performed through this same approach.
Do Artificial Disc Implants Restore Normal Spinal Mobility?
Normal disc motion in flexion and extension is quite complex. While total disc replacement is designed to leave the disc space mobile to some degree, is does not replicate "normal" spinal motion per se. Each implant design produces different motion patterns. It is unclear at this time if one specific motion is more important than another to maintain or simply if it is important to maintain some type of motion in order to lessen the stresses seen at the adjacent discs (as happens with fusion surgery).There have been some reports that patients who have had artificial disc replacement surgery have accelerated posterior facet joint degeneration, and this is felt to be due to the abnormal motion provided by the artificial disc. It is too soon in the clinical experience to say whether or not this phenomenon is real and if it will become a clinical problem.
Does Artificial Disc Replacement Prevent the Development of Adjacent Segment Disease?
The long-term potential benefit of maintaining spinal motion with artificial disc replacement is believed to be less degeneration and problems with the surrounding discs. However, this is only a theoretical benefit, as no good long-term medical studies have been done (these procedures and devices are too newly available). Only after a longer follow-up time and additional medical studies will we know if this believed benefit is real.