The Spinal Kinetics M6 artificial cervical disc is designed to replicate the structure and performance of a healthy disc. Its innovative design incorporates an artificial nucleus to allow shock absorption and a woven fiber annulus for controlled motion in all directions.
These characteristics accurately replicate the healthy disc, allowing the implant to work in concert with the remaining human discs. Unlike earlier "ball-in-socket" implants, with M6 the resulting natural functionality of the entire spinal curve should provide the best chance for a full recovery, and prevent or delay additional adjacent level degeneration. This "Quality of Motion" is a major benefit not available in any other implant we have seen!
Watch a video on "The evolution of Disc Replacement"
Disc Replacement Options and "Quality of Motion"
Disc replacement implants fall into two distinct categories, compressible, and non-compressible.
Non compressible devices include Fixed Center of Rotation; ball-and-socket designs, and Mobile Center of Rotation; mobile core and ball and trough designs.
Aside from the obvious lack of shock absorption, non-compressible implants have several distinct characteristics.
A healthy disc provides a graded resistance to motion. Although, these non-compressible disc replacement implants retain motion, unlike fusion, the motion is uncontrolled. Adding load can make the motion characteristics even more unpredictable. The result can be motion which is not intended in the design or is sporadic. This is also referred to as stick-slip-friction. Because of this, facet joints may be overloaded, muscles are required to work harder, and adjacent level damage can occur. On the other hand, in a case where additional stability is desired, due to advanced disease or other factors, an implant with a fixed center of rotation, may be desired.
Compressible implants have the obvious benefit of shock absorption protection, but can also provide the required graded variable resistance to motion like a healthy disc. One of the first implants to achieve this was the Bryan cervical disc. Although this implant provided graded resistance, calcification was reported in as much as 12% of the cases studied. This issue has been resolved in more advanced implants like the M6 Cervical Disc. By provided the graded variable resistance, replicating a healthy disc, the M6 reduces facet and adjacent level complications. This "quality of motion" under load not only maintains a physiologically correct motion dynamic, it also is not as sensitive to placement variables as the earlier implants.
Careful evaluation by experienced surgeons is critical to insure that the correct implant options are chosen for each level based on many factors. The doctors at Stenum hospital have the experience and the implant options needed to make sure the best possible outcome is achieved.
