After having back surgery done you will have to allow from 3 to 4 months to allow the back for the bones to heal properly.
So that means you must avoid any physical activities for at least 4 to 6 weeks to allow your back to heal so you won't do anymore damage to your bones and back.
So expect to be off work for at least 6 weeks after you have back surgery.
Full recovery from back surgery can be as long as a year though but you should be able to return to work within 6 weeks.