Pain mgt physician wants my wife to have SIJ fusion. Opinion?

[r1013]

My wife was a very active person, hiking and lifting weights, until autoimmune problems started back in 2014 at age 40.  Now at 48 y/o her rheumatologist and immunologist have her almost back to normal.  One thing lingering is hip pain from ankylosing spondylitis which is a big thing keeping her from working.  Luckily it's not getting worse now that she has the proper treatment. She seen her Orthopedic physician approx 5 years ago and he sent her to pain Mgt as there was nothing he could repair. Pain Mgt over the last few years has decided its her SI joint after she did get relief from INJ into her SIJ. Her Pain Mgt has recently received training with Cornerloc, which is a product that fuses the SIJ using an allograft. I went to a forum reading Pain Mgt docs discussions about SIJ fusion in general.  Reading there post, 80% seem most are against it citing many problems with the spine and hip that can result from the fusion.  One of them who was ok with it, had performed 20 Cornerloc procedures over the last 2 years with only 3 failures, which matches other statistics I have seen. I called her orthopedic physician to ask his opinion. He was not familiar with Cornerloc itself but he was familiar with and trusted the pain Mgt physician. He agreed it was a logical next step since the INJ worked temporarily. I don't like the idea of a general surgeon turn pain Mgt physician performing an SIJ fusion. Even worse this will be his first!  On the other hand, I do personally know him and he was a vey good and trust worthy general surgeon. I also don't like the success rate of approx 75%. We are not stupid. We are both nurses and I personally spent 4 years working in orthopedics before moving to heart surgery.  What I do agree with, is that my wife's pain is very debilitating.  She is very tired of taking opioids and wants off of them and she feels this will help her to do that and get her life back.  Any opinions?