There was much talk about revisions at NASS. One session included a discussion about revisions and revision approaches by Dr. Salvador Brau. He's one of the top ADR approach surgeons who works with both Regan and Delamarter. Bertagnoli also presented 2-5 year results during this session and participated in a wonderful discussion about revisions.
I know that Bertagnoli has revised Charite to ProDisc. He has also revised ProDisc to another ProDisc. The original implantation was not his... a subsided, undersized ProDisc-L was replaced by a properly sized and placed ProDisc, using the same keel slot. Note that the vertebral body was not destroyed in removing the ProDisc.
Dr. Brau has removed ProDiscs and Charite's... some many months after implantation.
In anterior surgery, a serious problem is the inability to mobilize the great vessels so you have enough room to remove the prosthesis straight out the front. With a Charite' you can remove the core, then remove the plates individually, from an oblique angle... they do not have to come straight out the front.
With a ProDisc, you can also remove the core separately. Once that is done, the plates can be broken loose individually. There must be enough distraction applied to allow you lift the plate enough to clear the keel. Once that is done, the plate can be removed from an oblique angle. The short keel of the ProDisc lends itself well to easy removal... even at L4-5 - the problem level. (The bifurcation of the great vessels makes this level the toughest to deal with.)
I asked Dr. Brau to comment on his L4-5 ProDisc removal and speculate about removing a Maverick. Note that a Maverick does not have a core to remove. It will not be possible to apply enough distraction to clear the keels and remove a Maverick from an oblique angle. It can be impossible to mobilize the great vessels enough to allow the prosthesis to be slid forward - straight out the keel slots. If this is the case, the vertebral bodies will need to be seriously damaged to get the device out.
Mark
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