I'm very proud of myself because I have made the decision to have an artificial disc replacement for a damaged disc at the L45 level. Now that I'm ready to take this step, I'm asking myself what I hope to get out of the surgery. Pain relief is number one. What do other people look for to say it was or wasn't a success?
Five years ago (in 2004), the Food and Drug Administration (FDA) approved the lumbar CHARITÃ artificial disc. This approval was made based on a two-year trial conducted by orthopedic surgeons at 14 different clinics around the United States.
The CHARITÃ artificial disc has been around much longer than that. It was designed and tested first in Germany before it was brought to the United States. The CHARITÃ disc has three-pieces. There is a sliding core sandwiched between two metal endplates. The sliding core is plastic and the endplates are metal made from cobalt chromium. The endplates support the core. They have small teeth that hold them to the vertebrae above and below the disc space. The sliding core fits in between.
Disc replacement is meant to replace spinal arthrodesis (fusion). The main difference between spinal fusion and an artificial disc implant is motion. Fusion stops vertebral motion at the level of the fusion.
The disc implant allows continued normal motion in all directions -- even including a small amount of segmental translation. Segmental translation refers to the sliding motion of one vertebral body over another. With a fusion, there is no segmental translation at the fused level. Just the right amount of translational movement is needed for normal spinal motion. Too much translation and the segment would be unstable.
Various measures were used to study the outcomes. Pain, range-of-motion, function, disability, work status, and reoperation rates are commonly evaluated before and after surgery. X-rays measure differences between flexion, extension, and translation of the vertebral segment operated on as well as the adjacent segments (above and below).
Even without a significant difference in all of the outcome measures, decreased pain and increased quality of life can result in patient satisfaction.