Our costs are hard to make sense of because doctors/hospitals/etc routinely charge 3 times the amount that they actually get paid. So, an average billed cost for an uncomplicated scoliosis surgery is around $150,000. But, the actual amount of money paid is a third of that (or around $50,000). The rest of it is written off in discounts.
That makes the real cost ($50,000) pretty close to the costs in Australia.
However, if you don't have insurance, then you're billed for the full, undiscounted amount. That makes not having insurance a double-whammy - you get billed three times the amount of anyone else, and you have noone to help you pay it.
But, I'll definitely keep flying to Australia in mind if we lose our insurance and my son ends up needing surgery.