You would be surprised at how much they are able to do these days. I have a severe scoliosis which was barely corrected at all, since I did not get to a doctor when I first had symptoms. By the time I got to see a doctor, I had finished growing and very little could be done except to fuse me where I was so it wouldn't get worse.
Now, 30 years later, the surgeon who did my last fusion, 1 1/2 years ago, tells me how sorry he is that he can't do more for me. (I'm thrilled, though, that he was able to do as much as he did!) He says that back when I had my first fusion, that was the only thing they could do. Nowadays, he says, they would never leave me like this. They could get me straight! I have a 75 degree curve, so that's pretty amazing! The advances in surgical techniques have come a long way.
Hope you get all your questions answered.
Emily