I too have had thyroid surgery, I actually had 4 surgery since my rsd started and as long as you have a doctor who knows about rsd. For me what they did I had constantly low dose of ketamine. They then about 30min before the surgery they started to give me iv pain medacine, I use demerol but everyone is different. They then kept giving me the pain meds during the surgery, after the surgery and when I woke up the kept giving me the demerol and my surgery was a great success and I woke up with just low pain like a 4. I have had surgery and they didnt do that and I cried hours afterwards in a big flare, the thyroid surgery though, I didnt cry at all and didnt go into any flares. The surgeon also made sure that I had pain managment all on board and also an anesthesiologist who knew what rsd was and how to keep the right amount of meds. I was actually very lucky with the surgery, my problem all started with a golf ball sized lump on my thyroid. They asperated to see what it could be and to make sure I didnt have cancer and it came back as non canceris but 2 days later it came back but this time it hurt. So they decided to remove it. When I wolk up my doctor came to me and told me that it was a great to push for the surgery as what was not to believe it as cancer before came back possitive for cancer that wasnt detectable before. So I ended up being really lucky that it hadnt spread yet.
I wish you luck!

Samantha