This was recommended for me by my pain doc, also an anesthesiologist, but it turns out that it's not as useful in people who have had back surgery, as it's done assuming the nerve to the facet will be where it was when you were born, and not moved around by a surgeon's hand.

I read lots about it at the time, and it seems like a good procedure when the doctor can identify the source of the pain. A firend of a friend who had a bookbag dropped on her head by a student, and has severe chronic pain, gets them every 6 months, or year, and it's working for her.