The idea is to use a Block (in my case stellate ganglion, in your's--a lumbar sympathetic, I believe) as a preemptive strategy, directed at the area that will be operated on.

For example, I had additional surgery after the onset of RSD, and I underwent a SGB immediately beforehand. The block worked so well that I thought the surgery had resolved my pain issue, unfortunately that wasn't the case. It made my post surgical recovery very easy. It's impossible to predict if I had not had the block, that I would have exacerbated my RSD and possibly caused spread, but with RSD, it's always better to proceed cautiously. A block is no guarantee that surgery might not make things worse.

Traditional RSD pain is very severe. If you can recall how intense the pain is stubbing a toe? Fortunately, that only lasts seconds. RSD pain is a similar type of intense burning pain, but it is constant, and over a larger area... Before I started on the right meds, I sometimes fantasized about having my arm amputated (not uncommon)...