The first one when I was about 55. I was in a lot of pain for a long time and tried everything to avoid it. Finally bit the bullet after trying everything else. It went good BUT the jackass surgeon didnt install the screws and cage that I now know are standard procedure. I guess he thought the bones would just fuse without support. Everything looked great until my 3 week checkup when the X-rays showed the fused joints slipped. Took several weeks to get another surgery to install the hardware scheduled. The new surgeon was great and the surgery went well but I lost about 6 extra weeks of work. Anyway, I was pretty much pain free for the first time in years. I dont know the joint numbers, but the lower lumbar.
A couple years later I got into a car accident and got a compression fracture in the next joint up. Again I tried to avoid surgery for a year or two and finally went back in. The surgery went well and was pain free in a couple weeks. Then it suddenly went to shit and the pain was worse than ever. I saw the doc for about a year with the worst pain ever, finally becoming bedridden. They couldnt really say what was wrong beyond some of the screws coming loose. Finally went back in and it turned out the previous fusion was infected but they didnt find that till they cut me open. They had to fuse a couple more joints to get enough screws in for support. By this time I was in my 60s and things dont fuse as fast as you age. But that surgery was succesful and pretty quickly was pain free again. But I think almost all of my lumbar is fused now and I lack flexibility in my lower back. That was almost 4 years ago.