[annapurna]

With severe facet joint arthritis, you're risking continued growth of the facets and spurring if you use and ADR at L4-5. You could reach the point where the facets themselves begin to damage the nerve roots exiting at that level and need surgical correction. If you have at least two competent (in your opinion) surgeon who are refusing ADR at L4-5, you're probably too bad to risk it. I understand that you're concerned about fusion driving future surgeries but the spurring could driving them as well and, if the surgeons are right, is a lot more likely as you're already on the edge with your facets.

If you haven't got at least two opinions, though, definitely get a second or even a third. One surgeon's severe facet degeneration is another's mild to medium so you've got some wiggle room in interpretation. Another thing you could do is roll the dice on facet joint replacements and hope that they're fully developed in time if you end up needing them. They are out there and have been in use for a few years but the number of surgeons willing to attempt that in the world is still very low.