I had that same surgery over a year and a half ago. Don't worry about the anesthesia, The second they had the needle in my arm I was out, The stuff they use for surgery is far more potent than what they used when I had my wisdom teeth pulled.
I'd be more worried about the time after the surgery, Since your only having the upper jaw worked on you may or may not have to stay in the hospital overnight. That was by far the worst part of the whole deal. I had a hard time sleeping, swallowing was difficulty and I had plenty of bloody noses. Everything after that should be a lot better.
A few things I would get if you haven't already are the ocean spray nasal spray because you will have a seriously runny nose with blood possibly. I'd also get a large variety of different foods you can have that you rotate every other day. I know that half way through the ten days that I had my mouth wired shut I was sick and tired of ensure, v8 and tomato soup. I found that milkshakes were a great way to get a large amount of calories and have something that I never grew tired of.
If you have any questions feel free to ask I'll do my best to answer them.
@benjaebe: That was my biggest issue with the demo. A lot of the options were unavailable, couldn't mess around with the inventory and the text is ridiculously small (but thats my own problem). Other than that I really like the immediacy of the combat. I also love having the move to point option.