[annapurna]

More of an answer than you thought you'd get:

In real life right now, I can't think of too many people who can tell something is wrong with their back early enough to be able to go through the whole medical game and wind up with a surgeon ready to operate without having had some degree of facet arthritis develop. As experience develops and surgeons and GPs become more aware of ADR and facet replacements and as experience with those techniques develops, I suspect that we'll see people having surgery offered to them earlier and easier. Back when knee fusion (yes, KNEE fusion) was the only technique available, knee surgeries were delayed as long as possible. Now that everyone is aware of multiple techniques for knee repair, knee surgery is generally offered really early into the diagnosis and treatment plan. I suspect that ADR and facet replacements will lead to the same gradual change.

As for why facets are read as severely damaged in the US and mild in Germany, some of it is experience and being able to judge when too bad is too bad but some of it could easily be the view of malpractice. The US surgeon could be sued just because you, the patient, thought you could get away with it. The Germans can really only be sued if true mistakes can be shown so they might be willing to accept more risk. It's also true that many inexperienced people compensate for their lack of experience by being very conservative. I see it a lot with young engineers at work. Of course, many go the for opposite end and take inappropriate risks, so it's still up to the patient to figure out if the surgeon is doing the "right" thing.