I'll just add that I too had lower back pain before and now I hardly have any back pain. Only happens when I do something stupid like lift a keg without any help. As everyon pointed out, the compensation issue is huge for the rest of the joints in the train. My knees had pain, my lower legs had pain and most certainly my back had pain, mostly lower back. I've seen this discussed quite a bit here and a lot of folks get resolution from surgery.
Pre-surgery, I honed in on the fact that I was not bending at the knees and hips to pick stuff up from ground level. I found that that caused a major increase in back pain. So gardening, cleaning up the shop or backyard, loading firewood, construction on the house,...all added to the pain. Decreasing those activities helped. Now I do twice as much work around the house as I used to, without any pain.
I'm very optimistic for you. I think you'll see a major decrease after surgery.
Keep in mind, that the gait will take time to mend as will the limp that you'll get from surgery, if you didn't already have one. Those might add to back pain in the first few weeks of recovery. Might not. I think a lot of my pain in the knees, legs, and back went away immediately.