R.J.
My mechanic's daughter just had the surgery to correct it last year (after years and years of terrible migraines... she's a teenager).
What they did was to grind the skull down on the inside so that there was more room for her brain and then to create a skin "sling" as a double protectant to keep her brain up where it belongs.
She's doing fanatically. Short recovery time, and only 3 migraines in the past 18 months. (Whereas before she'd get between 4-10 a week)