Hi, Tim. I am a smoker 1-1.5 pks per day. I had lumbar and cervical fusion in 2006. I did not quit smoking completely but I did try my hardest to cut back before my lumbar surgery and for a month after until I saw that I was fusing. I wore a spine fusion stimulator that is recommended for smokers, diabetics, overweight people or others that are at high risk for not fusing. After my surgery I also walked. Starting with short walks (always using my walker) then extending to long walks everyday. Walking helps the bones fuse. Maybe this is a possibility for you if stopping is not working. Oh, yea, I also wore my turtle shell back brace for a long time when I walked and always carried my cell phone in case I fell. I used my walker for a month while walking for fear of falling. Wishing you the best and like Father John said the fusion can be a success but you can still have lifelong pain afterwards, this is my case too.
DDD, osteoarthritis, fusion surgeries C-5/7 & L-4/5 both in 2006, torn meniscus left knee 2000 & 2002, buldging disc L-2/3