I just had an L3-S1 posteriolateral fusion 2/3/10. So I have one 6" vertical incision down my back and one 4" horizonal incision on my hip. Slightly different technique my doctor does instead of using anterior.
3 weeks later I can tell you that much of my pre-op pain is gone. It's still early to tell if I'll get all of the relief I wanted from this, but I have hope as I'm feeling pretty good. I am wearing a custom brace the doctor sent me to be fitted before surgery. With a one level fusion they may not. But be sure to take care of your back after the surgery. Don't bend, lift or twist and follow all medical directions Most physicians agree that after fusion no NSAID's (aspirin, alevel, naproxen, advil, ibuprofen, etc).
Right now I have some "surgical pain" in that I can tell it's related to the incision or the hardware. And, this was my 5th spine surgery (I have very lax ligaments so all joints in my body, including the joints in my spine, move too much and cause problems). So even after 5 I can say each one was worth it and relieved so much of my pain. I can handle my post-op recovery pain much more than I could the nerve impingement pain I had pre-op.
The two best things I have for recovery are my toilet seat riser. It fits in my toilet seat and rises it about 5 inches at least. You can find them at big name pharmacies but I got it for a great price on Overstock (I wanted, and got the one, that has a "lock" so it fits in any size and it won't wobble when you get up and down). I learned this last time (1993) when I came home from the hospital and getting down to standard toilet seat height was hard. The second thing is a grabber, also available at pharmacies. It's about 24 to 36' long with a claw on the end. Helps you pick up everything from clothing to dropped tissues, dropped food, helps me put cat food in the cat dish when hubby's not here, etc.