Re: Working after Spinal Fusion
It could well be worth getting a physio assessment. If you're hypermobile, slightly bizarrely it is possible to have tight hamstrings and hip flexors without this being obvious to most people - I do, and yet could apparently get way down into most of the standard stretches that they give you at the gym. The hypermobility physio was quite specific about how I move, and all of a sudden I was able to discover just how tight they were - the thing was, doing the stretches the standard way, I was "giving" in other places, so that it had the superficial appearance of the necessary stretch without reaching the parts it needed to.
The other thing that may be helpful, and is again physio-ish, is as has been suggested above, to work on core activation. This, and leg strengthening may well help a great deal, and also it may be that minor changes to *how* you bend will make a great deal of difference.
The other thing is simply time - I had surgery at 20 and 29, and both times it just plain took time, but did get a lot better even after the 18 month mark. I hope that is comforting, rather than depressing, certainly how it's intended!
Diagnosed at 15 with 50° curve, but probably juvenile IS. Fused in kyphosis (by non-specialised ortho) with a/p surgery T10-L2 @ 21, posterior only revision surgery to correct kyphosis @ 29. Now 38 with further revision surgery and extension of fusion to sacrum required to correct residual kyphosis, restore lordosis and address spinal stenosis.