I'm not an expert, but I have learned that FDA approval is not actually necessary for treatments and drugs. Your doctor has a lot of leeway when it comes to treatment but she of course experiences more risk of accusations of malpractice when prescribing off label drugs or unapproved treatments. insurance will also rarely cover treatment that is not FDA approved. the requirement for FDA approval generally has more to do with your legal ability to market the drug, treatment, or product.
That's actually super interesting and kinda great to hear, I guess my follow up question is obvious but would insurance companies cover that kind of procedure in the US? I get the impression it wouldn't be.. but if out of pocket.. I know I'd absolutely do anything for my kid.