Disc replacement technology is evolving, and Todd Lanman, MD, said he’s interested in developments that affect the longevity and function of implants.
Dr. Lanman, a neurosurgeon at Los Angeles-based Cedars-Sinai, will be featured in an upcoming episode of “Becker’s Spine and Orthopedic Podcast.” Below is an edited excerpt.
Question: What’s exciting you in [dis replacement] right now?
Dr. Todd Lanman: In the cervical spine we’re seeing more devices being approved and being investigated, and there’s some really interesting things that are happening.
One is that there are some new devices coming out that are able to preserve angulation or alignments of the spine better. The new devices provide a curve of the neck. So your neck should curve backwards, and this artificial disc still allows mobility but helps maintain the alignment properly. A lot of the discs that we have now really let your neck set itself where it wants to go, and because of phones and laptops, we tend to flex forward mostly. So you can have kyphosis or that flex forward, and most artificial discs will allow you to roll forward. It takes a lot of rehabilitation and strengthening of the muscles to really keep the head in alignment. So there’s new technology coming out that may help that and make that process much easier for the patients.
The other thing that’s happening is viscoelastic discs, which are soft core discs, have gained some traction outside the U.S. What I think people need to really remember is any implant that moves, whether it’s a total hip or total knee or shoulder replacement, artificial disks in the neck or the low back, will have wear. How fast does that happen? We do know that the more common implants that have hard, ultra high molecular weight, polyethylene cores, for example, with titanium, tend to last as long as 70 years. They’re still very functional but the viscoelastic course cores can allow motion up and down. Hard core discs don’t do that. When you look at the data carefully, though, there’s no real difference in the outcomes between the sets of patients. The soft core discs sound intuitively better, but they do not show any better outcome. What they are showing is the core is wearing out early, which means then you’re back to revise it. The soft core discs that are not available in the U.S. are also having some issues, and I’ve removed a lot.
