There are a variety of elastomer designs in the works. There was one that goes back to the 80's called Acroflex that was a disaster because the elastomer or the elastomer / metal interface would not hold up. Everyone seems to be excited by the concept of increasing resistance to loading that the elastomer provides along with compressability some translation... but very nicely controlled translation.
Another elastomer design that got a lot of attention is the Theken disc. It looks similar to the discover... more like a prodisc with an elastomer core, but the core is hollow and it has load sensors in it. Kind of science fictiony... but hold your blackberry near your belt and your disc beams it's data to it.... rats you out to your doc.... "Hey, you said you weren't going to play golf!!!"
Theken has had a very high profile for the last several years at SAS and NASS. No booth in Miami... they are still looking for funding to get to the next level.
The
M6 disc looks very interesting with a somewhat compresable core. It seems to have the same issues as other mobile core devices. I don't know yet how critical these issues are. Like other mobile core devices, problems are minimal with good implantation and no complications. I am looking forward to watching the M6 make progress. It has an elastomer core, but the core is not bonded to the plates, so the problems associated with separation will not be present, but then they don't take advantage of the increasing resistance of the elastomer. However, they do try to make up for that with the woven annulus like capsule around the core. It's got a lot of pieces and I wonder about the longevity of some of the components.
I've talked at length with many surgeons including Z and B about the elastomer designs. I won't try to put thier thoughts down... as there can be too much lost in the translation.
I will say that as with the older designs.... all of the differences from one device to the next come with advantages and disadvantages. It's hard (or impossible) to know which ones are important to you unless you are on the wrong side of a failed surgery. It's tough to base a decision on the marketing spin you get about the devices. Do your homework... make informed decisions.
Mark