I watched a similar procedure on "The Operation" on Discovery Channel. While it appeared to be very barbaric and brutal to the patient, the end results were amazing, not to mention life changing. I think the girl in the program had a similar amount of correction to your sister and the end result was almost beyond belief once the post-operative swellings had gone down.

Purely OOC, did your sister retain her natural teeth in her upper jaw? From watching the TV program it wasn't clear but I imagined that that was the surgeon's objective.