Sosi,
I can only give my own experience so will. In 1989 I had my first spine surgery at L5S1. It was a big open discectomy. Approach was bilateral so have a horizontal scar there.
I did have another surgery (percutaneous discectomy) on L4 in '92. L5S1 bulged again and was thought to be my worst disc situation.
Ok so from 2000 and 2003-06 I was offered a 3 level global fusion, a 2 level ADR, a hybrid surgery with L4 ADR and L5S1 fusion.
I did none of them. I started to feel better finally in 2005/6 and after having diagnostic films was told that I had autofused at L5S1.
So we're talking about 20 plus years from my original injury ( I was 28 at time of original injury) and am 58 now. I still have pain at times and I do take a low dose opioid mediine daily.
I think I'd say in my case it was between 20-30 years for autofusion of L5S1 tho when it happened what an amazing difference re level of pain not felt. I'm hoping L4 will do the same thing given enough time
