There are three cervical artificial discs approved by the FDA: The Prestige Artificial Disc, The Pro-C Artificial Disc, and The Bryan Cervical Disc. A comparison of these total disc replacement devises is useful in understanding the advantages and disadvantages of each design.
The basic premise of an artificial disc is that a motion sparing devise (the disc) will maintain a natural range of motion while protecting the adjacent disc from wearing out. The importance of the stabilization design differences of the discs, becomes apparent when comparing to the revision potential designs.
The Bryan Disc: The Bryan Disc design utilizes precision cuts into the vertebrae similar to those used in artificial knee replacement technology to create a precise mating of the implant to its adjacent vertebrae. In the Bryan Disc design, removal of the implant will leave normal vertebral anatomy allowing simple insertion of a bone graft and plate during the revision operation. In many cases this revision surgery can be done as an outpatient procedure.
The Bryan Disc is only an option if the patient does not have cervical kyphosis. (loss of the natural curvature of the neck). If kyphosis is present, it is likely that this option will not relieve the patient’s symptoms, and the disc will be converted to a fusion down the road.
Prestige Disc: In the Prestige Artificial Disc design, stability is achieved through the use of screws that attach the implant to the bone. The Prestige Artificial Cervical Disc is constructed with stainless steel, and has two articulating components (a ball on top and a trough on the bottom) that are inserted into the disc space and attached to the vertebral bodies on either side. The components of the disc function like a joint, replicating the motion (yes and no motion) and natural curvature of the spine. The Prestige Artificial Disc is an option for a patient who has a slight loss of lordosis or mild adjacent segment degeneration.
Pro disc C: The Prodisc C design uses a center keel to stabilize the implant into the adjacent vertebra. The vertebra need to be chisel cut or drilled to accept the keel. This keel is cut into the vertebrae and displaces bone upon insertion. The keel is a powerful stabilizer and if the implant needs revision, the devise may be difficult to remove. Since bone is lost during insertion of the keel, a bony defect may be left after the implant is removed making revision fusion a more extensive surgery than designs where the keel is not used.