I've been wondering about this one for a while too. I have had scoliosis (the correct term for this!) for about 10 years, and had a spinal fusion to stop it getting any worse. I got a Class 2 medical with absolutely no problems, but I'm considering going commercial, and have no idea whether I'll be able to get a Class 1.
The only thing I can suggest is that you call the CAA, go through to the medical certificate people, and ask! That's what I've been trying to do. And if you get through before me, let me know what they say!
Best of luck... it's a bummer when something out of your control lets you down before you have the chance to muck things up yourself
