It seems that it is a special kind of disc replacement to be used for conditions such as degenerated discs and cord compression. In some cases it is necessary to fuse a couple of vertebrae, but sometimes a disc replacement can be performed - it seems here that some cases that would originally have warranted fusion may be able to be treated with this device instead, without fusion.
Traditional disc replacements are made from hard materials but this one seems to be made of silicone. Supposedly it opens up the spine better and helps with blood supply and nerve freedom.
Unfortunately it won't work for spinal deformity, but it may be interesting for those who are suffering disc degeneration above or below their fusion. Thanks for the link!