Jaw surgery candidate who determines best?

[Purkulator]

I am just wondering, when the ortho/oral surgeon sees a patient and says that you need this or that type of jaw surgery, how do they know that? I mean is there certain measurements shown in the x ray where when those measurements exceed a certain value, then the person needs to get X surgery to lengthen/shorten the jaw? While if it is only off by a little, then the person can get off with braces only?

Also who is it best to see to get an assessment as to whether you need surgery i.e. tell you the most accurate assessment as to whether you are a surgery candidate or not?

Thanks a lot!

[geijutsu]

I'd imagine folks with obstructed airway are the ones of fall in the need category, as it's not just a matter of teeth problem.

[brewer44]

I had a 360 scan (showed muscle, bone, fat, etc.) and they popped in the measurements that way.  Gotta love the future!