According to Dave Meltzer on a recent edition of The Wrestling Observer Radio, Shane McMahon will indeed be wrestling at WrestleMania 34 coming off diverticulitis and with a hernia requiring surgery, which he will likely be getting after the PPV. It seems that the main reason Shane is going to work through the injury and postpone the surgery is because it’s WrestleMania.
Meltzer also refuted rumors that the umbilical hernia is a work by WWE as Meltzer noted that those he asked in WWE confirmed that it is a legit injury. The only thing that could likely be a work according to him is the injury actually occurring during the beat-down by Kevin Owens and Sami Zayn.
Source: Wrestling Observer Newsletter