I imagine if you’re pioneering a new technique for medical surgery, you would practice on animals first. Then you would offer the surgery to people who were desperately ill and had no viable alternatives. Then - as the surgery itself gets credibility and you build up your own expertise - you would gradually expand to people with more and more benign conditions. Question is how this applies to cosmetic surgery.
On the one hand, I would think that animals are much more similar to people as regards to the functioning of internal organs than they are as to cosmetics. And at the same time, I would think the level of precision required for cosmetic surgery to be a success is much higher than the level required for treatment of medical conditions - the difference being that in the latter case it’s generally replacing/repairing a malfunctioning organ while in the former case it’s just about improving a natural appearance. So the question is about how these techniques are pioneered in the case of cosmetic surgery.
Of course, the above applies most strongly in cases where people are just trying to improve an appearance that’s already within the bounds of “normal”. If you have someone whose appearance was severely disfigured by some accident or fire, then there might be more room to experiment since anything might be an improvement. So I guess it’s possible that most cosmetic surgery techniques are outgrowths of techniques which were originally pioneered on severely disfigured people and later expanded to more ordinary people. But I don’t know if this is actually the case.
I also wonder about the training/experience of individual doctors. Suppose some doctor somewhere pioneers a new technique. And you’re some highly successful surgeon with years of experience with all sorts of other techniques but have obviously never done this one. How do you get in on it? Do you just read up on it, or attend some seminar where it’s described? Or do you actually intern and/or participate in some actual surgery under the supervision of the guy who invented it? This applies to ordinary surgery too, but ISTM - and I could be wrong here - that new techniques are more commonly being invented in the cosmetic surgery field, and also, again, that the need for this type of surgery is frequently lower than for other types of surgery, such that the risk/reward ratio of undergoing the surgery at the hands of a guy who never did it before might be different.