How long does the fontan operation take?

Relatively short. Actually performing the fontan operation is quite short, usually less than half an hour. However, patients are usually in the or for hours. It takes time to get things set up, and if there is significant scar tissue from previous surgeries, it can take quite awhile to expose the area of operation. Some surgeons use by-pass, others don't. Also, it can take a lot of time to control bleeding.