Voice surgery does one thing: it raises your pitch.
In the past there were horrible failures as surgeons just invented the techniques, those failures meant too high pitch and perhaps weakened voice or damage to it.
These days this is no longer the case with good doctors, they can raise it to a comfortable level this means female range fully, some can even change the resonance to the voice a bit, not all need resonance change but it is an option if one needs.
That's it.
What else can contribute to a voice surgery count as "failure"? Well, in truth once the pitch is in the right range, and if resonance modification was done too and properly then nothing. But as everyone knows speaking style makes a lot too and voice surgery has no effect on that.
Speech training as in, learning different infliction, tones of voice, soft speaking etc can benefit one's voice. Just because voice surgery does not deal with that does not mean they are horrible and failure, in fact voice surgery gives the benefits of being able to let the guard off, not being worried all the time, not having to put that extra effort and also saving your voice the damage, tiredness and exhaustion that often comes with the effort put in the voice to make it in proper range.
I've met people who went for surgery, those include people who had problems with their voice and people who had no problem creating the voice they want but instead could get tired, hurt or just uncomfortable of that feeling that you need to put an effort and keep guard or awareness on to it.
The result of those people were good, the pitch was in the right range, they didn't get tired or hurt, they said they could feel more comfortable with themselves as they aren't always aware of what can happen to their voice and of the effort put into it. Some spoke in feminine style, some spoke in a bit more masculine style, some of those with masculine style chose to practice more feminine style and some did not, either way it is unrelated to voice surgery which in my opinion had very good physical and psychological effects.
I am going to have my voice surgery soon, luckily in here it is funded by the government and done by a specialized doctor here, perhaps this (and the fact Israel is so small) is why I had a wider opportunity than most to meet people's results.
Those are my opinions over voice surgery, opinions formed after 2 years of researching the subject. I'd like to add that those 2 years actually had quite some changes and improvements in the results of vocal surgery, most probably due to experienced and knowledge gained by surgeons.
