Hi and sorry to hear about this erectile dysfunction. No man feels comfortable having this and talking about it is very challenging. I congratulate you for standing strong to fight the ED. I am certain the belly button surgery has no cause-effect relationship with this ED. they may make a rare association but not directly related. Also, what is your age? How low were the T levels? Do you get up with early morning erections? Is it with all sexual partners or a few? Do you have any other illnesses like diabetes? Do you consume alcohol/tobacco? We need more of these answers before we can get into specifics. having low T alone can explain this problem. But then, we cannot jump to this conclusion without having some more basic information from you. Also, looking for the case of the low T if that is the final conclusion is worth investigating. I will suggest you meet and discuss this problem with your doctor. Hope you find this helpful. Feel free to come back for more information. Wish you good health