How successful are surgeries to fix TMJ?

Tomorrow I’m going in for an assessment to figure out if I have TMJ or not and I was just wondering, if I do have TMJ (this is probably the case) and have to go in for surgery, what is the likeliness that my TMJ will be fixed? I’ve heard a few horror stories from a few people who heard from a friend who heard from a friend who knows someone who knows someone whose second cousin twice removed had some disastrous TMJ surgery which really amounts to nothing.

So fluther, do any of my fellow jellies know about TMJ fixing surgeries and how successful they tend to be? Thanks!