My son had to have a major spine surgery to correct his. I was told there was no connection to CF, but I really wonder about it. I've read differing opinions, and even one journal that stated that children with CF should have bone scans done every year.
By the time we caught Jordan's kyphosis, it was too late to correct it with a brace. His CF doctor said it was very important to correct the kyphosis, because it was putting pressure on his lungs. I think if you have an opportunity to put on a brace, and let it correct that way you should do it. Jordan ended up wearing a brace for six months after the surgery anyway. I wish we'd caught it soon enough to avoid all of that pain for him.
It did take Jordan a year to get back to his pre-surgery FEV1. It took even longer to gain all of his weight back. It was really tough on everyone, because even the little things like bathing, dressing etc. he needed help with during his recovery.
If your child ends up having to wear the brace, I'm sure you could loosen it during treatments to allow the lungs to fully expand. I'm sorry you have to worry about it. It seems like CF is more than enough for a kid to have to handle.
Stacey