Aww poor Elvis, yeah we have quite a few pups with umbillical hernias come in and they usually do wait to fix them when spayed/neuterd. Since they're there and won't have to do multiple surgeries. There can be different hernias and I'm not saying this is the full complete answer but basically hernias are where there is like a tear (I guess you would say) in the under layer of the skin allowing for part of the inside to kinda slip out, big ones are more of a worry but small ones they don't seem to worry too much about, they just keep an eye on em. I hope that makes sense... lol