[sharman]

Allan, I am sorry that your condition is so bad. Still, the fusion/ADR hybrid looks like a good surgery. You get the ADR protection for the rest of the spine, and at L5/S1, you are not trying to force an ADR where fusion is the better choice (and once less level for facet worries). You have every reason to hope for a good result.

I agree with you, a keel at L4/5 poses real concerns. A keel could make things more difficult if you ever need the device explanted via a lateral approach. Of course, if you need a lateral-explant revision, you're in trouble already. I am hopeful on two fronts, tho. First, that post-Charite discs will have fewer complications requiring explantation. When I tried to google information on ADR revisions, I found many reports of Charite revisions, but few for the Prodisc. Second, that new surgical techniques and materials, like the Goretex barrier, will make anterior access feasible.

The question is, do you see advantages to the keel, and how do the advantages compare with the revision risks? Your anatomy may dictate the choice. On the Activ-L website, they say the keel should be used where the endplates are so deeply concave that the prosthesis can't make good contact.

Good luck with this.