Re: Repeated x-rays
At a rheumatology clinic recently (for my hypermobility syndrome and osteo-arthritis) I had to have xrays of some joints, and asked the radiologist about this. Her take was that PA requires significantly more radiation to achieve a suitable image because the spine is then so far from the plate, so she didn't see it being useful. However, there is of course the study showing the relative risks to be reduced for women especially and less so for men having PA versus AP xrays.
One thing which is for sure - there is no massive cancer epidemic in the women and men who are members of revision surgery forums and mailing lists, despite the fact that many of them had large numbers of xrays over several years as children, with each of those xrays being far higher dosage than a modern xray is. That is not to say that there is no risk - of course any excess exposure to radiation carries a certain risk with it, but I do find it reassuring that there do not seem to be big problems among the older age group who had their treatment 30+ years ago
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.