I train in this fashion as well. I stay away from squats, not just because of the back, I also have two reconstructed ACL knees (5 total knee surgeries). As you know, there are ways to "train around" our "condition" and still achieve great results and quality of life.
I wouldn't do fusion either. First, they go from the front, through the abdomen during surgery... potential and likely incisional hernia. I already went through that with an appendectomy. The odds on fusion... get this... "60% will achieve 60% relief." (quoting surgeon). Not worth the risk.
I admit, disc replacement is new to me. Sounds promising. At least they don't go in from the front for that... small incision in the back. I didn't realize there was a window though.
As bad as my back is, I believe from experience that proper attention will yield exponential relief. Besides the benefit from training, I use that "Teeter Hang Up," stretch, and medicate when needed. Once I understood the problem, found a good doctor, followed a good therapist's instruction, I was able to come a long way. I will maintain what I'm doing unless a doctor can tell me that disc replacment will guarantee I can play basketball again.