I have had a second back surgery in Oct 2013, almost 2 years post DS. Losing the weight really only helped me be more mobile. Did not fix the reason for the surgery. My back issues are getting worse again. I know, at some point, my cervical spine will need surgery but I suspect my lumbar is also heading for a third one.My mom had back surgery and needed one of those terrible braces. It's one of the reasons I had wls in the first place, so I hopefully wouldn't need back surgery.
I hope your losing weight helps you avoid back surgery.