Staging is no longer really done...

Blocks are the standard as a precaution for those with RSD receiving surgery. I had a Stellate Ganglion block when I had hand surgery post RSD and had no problems with spread. The SGB lasted for 3 weeks and got me through the worst of recovery.

How long will the block they're planning last? The kind done in child birth wears off so quickly it wouldn't help for RSD in regards to surgery.

Ketamine is often used in anesthesia for RSD surgery now, so you might want to research it as well. The main thing is your surgeon experienced with RSD? Have you had a 2nd opinion that surgery is urgently needed?