Has anyone had this elastomer disc installed?

[back2lifeplease]

Just got an email from Dr. Bertagnoli and he is saying that he prefers this elastomer disc to the M6. Anyone else have any experience with it or know anything about it?

LP-ESP® Lumbar disc prosthesis . FH ORTHOPEDICS (FHO)

As always, Thanks!

[annapurna]

Exerpience no, opinions, especially free opinions where I don't have to be right, yes.

The basic approach, a variable modulus core bonded to two end plates, is pretty much the same as the M6. They don't have the fancy sheathing around the core on this one but you might regard that as a positive - one fewer thing to cause problems. The way this ADR achieves the variable modulus is interesting, a core of compressible beads, rather than M6's variable modulus solid material. The M6 has the benefit of being simpler there but it's difficult to say if that's going to make any real difference in performance.

If you'll permit me to be blindly opinionated, I am concerned with the use of bonded designs without a good theoretical model of how those bonds handle fatigue loading: many, many cycles of relatively low loads. I've said that we don't have a good model of wear either, but wear is generally a slow failure mode so you'd hopefully suspect something was happening to your old ADR before it went completely bad on you. Fatigue loading, depending on how the failure occurs, could lead to quick failures and go without giving you warning. To balance that and to give both these folks and the M6 folks credit, they did do high cycle fatigue tests so they do have data in hand to say there isn't going to be a problem. Lab bench-type data doesn't always translate into real world applications but the testing engineers do typically try their best to mimic real life.

My other blind bias is against French engineers but that stems from a different industry and a time when my company competed agaisnt a French company. Not particualrly relevant but it does explain some of my bias here.

[Harrison]

This is interesting, as Dr. B's involvement with the development and surgical placement of the ProDisc goes back many years. How did these conversations with a non-ProDisc start and evolve?

Jim, I didn't know that you shun "freedom fries."

What's interesting is the explanation of engineering behind the disc:

The LP-ESP disc prosthesis is the result of 10 years’ research, using state-of-the-art techniques and the work of the Pitié Salpétrière hospital in Paris, the CEA (French Atomic Energy Commission), the University of Paris 6 and the collaboration of OSEO Innovation (ANVAR). The disc is composed of two titanium alloy plates, separated by a deformable part whose purpose is to allow the disc to move naturally.

The French CEA? ANVAR? Seriously?