Hi Vicki - I understand your frustration. I was originally diagnosed as undifferentiated SpA with no evidence on imaging.
I have my neck fused from C5 to C7, thoracic fused T7 to T9 with a rod and I have had several surgeries on my lumbar area. I have so many bulging discs that the nerve pain is unbelievable. Also have osteoarthritis/spondylosis.
I was diagnosed without my labs indicating inflammation and/or x-rays not showing any disease. I have inflammation in entheses in my spine, arms, and legs, a torn hamstring, and labral tears in my hips. I also needed a left hip replacement - where I had an orthopedic surgeon perform the surgery. The pain is much better following surgery.
Your questions are good ones - and I am sorry that your physicians didn't/couldn't answer your questions regarding spondyloarthritis and surgery. But I wanted to offer up that I have had no ill effects or issues with my fusions relating to my diagnosis of spondyloarthritis/AS. My neck was originally fused prior to my diagnosis. It just got worse and the next level needed to be fused - which is an orthopedic issue.
When my diagnosis changed to nr-SpA, I had a very hard time with enthesitis - I could barely use my arms, and my feet hurt constantly as well as severe pain in my Achilles. My whole spine felt like it was on fire from the enthesitis which wasn't evident on imaging. But I was diagnosed at that time with nr-SpA. I was diagnosed with AS only when the inflammation was evident and my labs indicated it.
"Ankylosing spondylitis also may cause bone spurs. This rare arthritis causes spinal inflammation. Over time, ankylosing spondylitis fuses, or connects, the small bones in the spine (vertebrae). The body responds by forming spinal osteophytes."
https://my.clevelandclinic.org/health/diseases/10395-bone-spurs-osteophytes#:~:text=Ankylosing%20spondylitis%20also%20may%20cause,responds%20by%20forming%20spinal%20osteophytes.
In more depth - "Sacroiliac involvement is a hallmark of the disease and is required for diagnosis. Plasma cells and lymphocytes infiltrate the sacroiliac joints, both the synovial and ligamentous portions, resulting in subchondral edema, synovitis and joint effusion. The inflammatory infiltrates later lead to bony erosions, healing with new bone formation, which progresses to ankylosis. " https://radsource.us/ankylosing-spondylitis/
I am hoping some of my story helps answer your questions. If not, sorry for rambling on and on ...
With regards - Rebecca (community moderator)