I wonder about this as I have spondy-whatever (actually retrosthilesis about 3-4 mm. lateral displacement). Two ADR docs who recommend fusion and ADR at L4-L5 say this shouldn't be a serious concern. But I wonder how strong the keel really is. I haven't researched this enough, admittedly.
http://www.spineuniverse.com/display...rticle114.html
Any input would be greatly appreciated.
Allan