Hi there. I too am undergoing orthodontia for the next 2 and half years due to TMD and problems with my open bite, misaligned teeth, etc. After the 2nd year of braces, I will be facing orthognathic surgery as well. However, my problem is that my upper jaw is too far forward and my lower jaw has been pulled out of the socket after years of trying to realign with the upper. I wore an upper splint 24/7 for 14 months which allowed my lower jaw to move back and up into the socket where it should be. Because of the movement however, my anterior open bite became even more pronounced, and only one molar on the right side touched the other tooth. None of my other teeth touched at all. My orthodontist believes that the teeth need to be re-aligned before oral surgery will be successful; therefore, that's why I have braces now for the next 3 years (I started wearing them in Dec. 2004).
I've heard that a procedure called Le Fort II osteotomy is what I may have to have done in the future. People I've talked to having this procedure after treatment from my orthodontist have said they were off work for 1-2 weeks, on a liquid diet for that time, and then gradually returned to normal eating. They had facial numbness for a period of a few weeks to months but all have been satisfied with their results, as sensation and full range of motion returns. I have noticed the people who had it done seemed to have a slight change in their facial appearance before and after surgery, since it will change your jaw alignment.
But not having actually been through the procedure, I cannot give you personal experience. Keep me posted on your progress and hopefully someone out there will respond to your post who has had the type of surgery you might have.
Good luck to you,