Pre-emptive ADR?

[fortitudine]

In the "to fuse or not to fuse" post, Allan/ans asks about "pre-emptive ADR" at a level above current damaged levels. That's an interesting concept - has anyone seen any studies or discussion? I know that my NS here wanted to do a pre-emptive cervical fusion - fuse the perfectly healthy level above while they were in there because it "would probably go eventually and it would be too hard to fuse it later", and I don't really see that there is much difference, conceptually.