Quote:
Originally Posted by Jag100
What are "hypermobile" ADRs? What models should I be wary of?
Thanks,
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That's, unfortunately, a loaded question. Most ADR designs don't have any inherent resistance to physiologically correct motion directions. That is, if a natural disk allows you to move your spine in a certain way, the ADR allows it as well. The natural disk works with all of the soft tissue stabilizing the spine to create a spring effect so that the farther you move in a direction, the harder it is to continue moving.
Most ADRs move freely and don't provide any resistance so all of that spring effect comes from the soft tissue. To complicate it, the loss of disk height as the natural disk degenerates, return to full height post ADR surgery, and the effect of the stretching in the surgery to get the ADR implanted, all leads to potentially weakened soft tissues. That means you can have a situation post-ADR surgery where your facets can end up acting like doorstops and seeing damage. There's a lot of ifs and maybes in there but being careful to not over do it post-ADR surgery until you can start strengthening the soft tissue to protect the facets is important.
To my knowledge the M6 is the only ADR with inherent resistance to motion. It offers that and some degree of shock absorbance at the cost of a lot of other concerns that have been discussed extensively on this board. Personally, if offered two completely equal ADR options, I'd avoid the M6. If offered an M6 vs. an un-needed fusion, I'd use the M6 and just make sure I watch for the concerns that have been noted about it.