These are rarely done for CRPS since they can actually cause more damage. I'm glad it worked for the OP thus far, but anyone considering the procedure should do lots of research first and get a second opinion by a CRPS specialist.

I had one performed years ago which exacerbated my CRPS significantly and permanently. It's the medical procedure I regret the most after developing CRPS, and I even had surgery in the area of my original CRPS site without complications.

http://www.rsdinfo.com/html/crps-sympathectomy.html