Put a muzzle on her, one of the cribbing ones with the metal grates. She can't cribs through those, period, and can still drink and eat grass (but you may have to take it off for grain).
Also, take the sugar out of her diet. Some horses crib due to pain and stomach ulcers. Feed her beet pulp--my horse used to crib constantly in a field, and after feeding beet pulp and changing his feed... he's fine, with no cribbing collar. I'm not saying it's going to work miracles (my horse wasn't a terrible cribber), but it may help your problem.
But yeah, get the muzzle. The surgery sounds very risky (they all are, when you deal with nerves). I know there is another 'surgery' out there where they install cribbing rings in the horse's teeth... but I think your horse would crib through them.