Hope everything goes well. I know exactly how you feel (horse related back injury) I didn't require surgery but it sure knocks the confidence right out the window.
Start of slow and don't go beyond your comfort level for awhile. Stay in a safe area like an arena or round pen at first till you get your balance in order.
Its been over a year since my injury and I am finally just about back to where I was pre-injury as far as confidence goes. I have take to wearing a helmet when I'm going to be in areas with hard footing. I should wear it all the time but I forget to take it with me.
Let us know how it goes and whatever you do don't let it get to you and don't give up