SI joint fusion

Seen the pain doc yesterday. Seem to be chasing my back pain now. My symptoms point to an SI joint problem. However when he did an actual exam, pushing and twisting the SI joint I did not experience any increase in pain. When he was done he told me that if my SI joint was the problem I would have been jumping off the table. He did schedule me for a bilateral SI joint injection, he said if it brings me noticeable relief then the SI joint is the problem. I mentioned that I have very little external hip rotation and extremely tight hip flexors. Doc wants me to talk with my PT people about some more stretches.
He did mention that before we talk about anything beyond the injection he wants me to put some serious time into stretching, if after several months he will probably do another set of injections, if the second set helps he mentioned SI fusion. Said it is no where near as invasive as a lumbar infusion.
SO...fine folks of FABO, who here has had/knows someone who had the SI joint fused? What was the outcome?