Severin, it is a shame that the treatments haven't worked for you. They only helped Bratcat up to a point and then she would flare again. And she couldn't use prednisone as a means to get her out of flares indefinitely. Surgery was very scary for her (and us). There is always lots of what ifs and what will be's. But going in with a positive attitude instead of a defeatist attitude will help alot. When you are ready to accept that surgery may be the right answer for you, try to embrace it (as best as possible). Look at it as the beginning of a new chapter in your life.
I hope you have a good support system (family, friends). I think that is very important. Lean on them during this time and after surgery. It won't make the pain go away or the healing go quicker, but they can shoulder some of the anxiety and frustrations you will have. And they will be able to give you that push or pull when you need it.
As for pain, luckily there are pain meds! And the pain won't last forever. Bratcat had an epidural in the hospital. Came home with darvocet (percoset made her almost faint in the hospital). She only takes one pill at night to sleep (not every night). Sometimes she takes tylenol during the day.