My best friend, who lives in Sequim, had (I think) what you described as the minimally invasive laminectomy/microdiscectomy. She had to go into Seattle for the surgery because.... that's where you go for major surgery when you live in Sequim! (There aren't many doctors, and far fewer specialists on the Olympic Peninsula). I don't know the details of her problem, but I do know that the surgery did resolve her pain issues.
I'll be talking to her soon and can try to get more details, though it sounds like your back problems are a bit more complicated than hers. Hoping you can get some relief from the pain. Back pain is the pits, to say the least. Yours sounds like a real challenge.