Most of the time these days, what they use to put you to sleep is pretty easy. Not too many experience bad side effects. If you get a bit nauseated they can help with that too.
Sorry you have to have back surgery. Are they doing a decompression or doing something with hardware? I am sure you already received a second opinion and done all the conservative things you can do.
Hope the surgery goes OK, and that you have no problems with the medications you are on, and what they give you in the hospital. Be pro-active, and question everything. If some drug is missing, or they fail to give it to you on time, speak up. Same with pain medication after.
I hope all goes well for you. Sometimes it takes a bit for our members to post back to you. You will make some friends here. The PD forum has some of the nicest people I have ever met. ginnie