I had my thyroid removed a week ago today, and I have had zero
problems with my voice. I had a bad sore
throat for a bit from the breathing tube during surgery, but that was really it. I do local community theatre and was worried about my voice, as well, and the doctor (general surgeon for me) he couldn't guarantee anything, of course. I'm not sure how rare of an effect it is, though. It really can be the luck of the draw, I think.