Your post is spot on. I was recommended by an orthopedic surgeon to have spinal fusion at L5-S1 to correct spondylolisthesis ( vertebrae have been forced out of alignment). This was a year and a half after a ski fall that put me in a lot of lower back pain. I had managed to get the pain under decent control with meds, but still had occasional bad days. Being somewhat naïve in regards to this kind of stuff, I consented to the surgery. Four months post surgery, I was still in pain. They listed it as "Failed back surgery Syndrome". A fancy way of saying, "the surgery was a success, but the patient did not benefit". Advice: get at least one second opinion!