I started diving in 1988 when I was 33. I had my first surgery at 15 (removed the blown nucleous), the second at 17 (removed the rest of the disc) and I was miserable from pain, lack of strength in my back and at all the limitations I had at being active. The third surgery was when I was 35 when I lost a 2nd disc and had to have the fusion (thank goodness, I still have pain now but nothing like before I had the fusion). I had just recieved my DM cert (since swimming was one of the only things the docs said I could do although they would not have approved of me standing with tanks and weights on my back) before finding out I had to have the 3rd surgery and I am now an instructor and very active diver. I have metal rods and screws in the lower back where I had the fusion and other then the fact that I can’t bend at the waist, I have no limitations. I am much stronger and capable after the fusion then I ever would have been w/o it and there isn’t anything I can’t do if I feel it’s something I want to do and can do otherwise (w/o regards to my back). Do what you have to, to get well and prevent further injury (look for alturnitives to surgery if you can) but if that’s whats needed, it’s not as bad now as it was in times past (a friend of mind had his done just 2 years ago and he healed up and was back to full activity in 1/3 the time I was since the medical procedures have come a long way in that time).
I hope that helps.