I am very leary of any surgeries that require birds to go under anesthesia as I have very poor outcomes. I had a goose that broke it's leg and the surgery was a success, but she died a few hours later never coming out of the anesthesia. Spent a 1000 dollars and the goose didn't make it. I also had a duck that was egg bound who I also tried to save and that duck also died post surgery but likely that was due to egg yoke peritonitis as they had to break the egg inside to remove it given it was stuck to her ovary. The duck did not ever wake up following the anesthesia. Also, spent over a 1000 dollars on the duck that didn't make it. So, I would really think this surgery though as you may spend alot of money and the duck may not make it.
I'm sorry to hear about your birds. Thank you for sharing your experience, i shall take that into strong consideration. Do you know whether the anesthesia used was an injectable one or a gas one? I ask as one of the other replies mentions having higher confidence in gas ones over injectables.