Dude... thats some injury you have there. I had an my ACL redone a couple of years back leaving the muscle in my thigh area completely dead. My thighs looked like jello when I got out of the hospital. But you knoe what bro, it all came back after awhile. Saying that, you need to put your focus on getting your back fixed and on your scheduled physio.

Once that is over and done with and your back is feeling much better, you can resume your training with caution. Take care bro, here's hoping ur surgery goes well.