In the case of degenerative disc disease in the lower lumbar discs (L4/5 or L5/S1), there is another surgical option. In artificial disc replacement, the surgeon removes the damaged disc and replaces it with an artificial one. This surgery is done with the patient on his/her back and the surgeon operates on the spine from the front through an incision near your belly button.
The Charité artificial disc is a three-piece medical device consisting of a sliding core and two metal endplates. The core is made from medical grade plastic and the endplates from a metal alloy like that used in knee replacement components. The artificial disc allows the spine to move as opposed to a spinal fusion where the disc space is immobilized.
Prosthetic Disc Nucleus
The intervertebral discs that reside between each bone of your spine act as shock absorbers. The disc consists of a tough outer layer called the annulus and a soft, jelly-like inner later called the nucleus. The nucleus absorbs most of the shock as you move, keeping the spine supple and the outer annulus contains the nucleus keeping the spine stable. As you age, both the annulus and the nucleus lose some of their cushioning ability and more of the stress of movement is borne by the outer annulus.
In an artificial disc, the entire disc is removed (annulus and nucleus) and is replaced. An alternative is nucleus replacement. This approach replaces only the soft cushioning material of the nucleus, leaving the tougher outer annulus intact. The goal in this surgery is to reestablish the original disc height and to redistribute the stress back to the nucleus, like it is in younger discs.
In this surgery, a very small incision is made on your back, just like in a discectomy. A small opening is created in the outer annulus and a Prosthetic Disc Nucleus (see picture in left column) is inserted. In some patients, this insertion can be done using minimally invasive techniques meaning a small, through the skin out-patient procedure.