Shawn Michaels exaggerated back injury question

Hey Scott,
Every time Shawn's back injury is covered on documentaries, video packages, etc., they always skim over the details of that four years. How could he comeback from a career ending back injury, perform at a high level, and perform some of the craziest bumps at his age?
​Because Jesus, I guess?  Seriously, dude, he had SPINAL FUSION surgery, that wasn't something you can fake for time off, it was legitimate career-ending shit and to this day there's no rational explanation for why he was able to come back and still be able to wrestle at that level.  That's why it's all the more awe-inspiring that he was able to make an entire second career for himself and hold out as long as he did.  ​