Prior injuries are an excellent way for the defense to try to poke holes in a plaintiff’s case. They will often try to claim that the malpractice or the bad result occurred because of a pre-existing problem. For instance, if someone has had abdominal surgery ten, fifteen, twenty years in the past, and now needs a different type of abdominal surgery, the anatomy is going to be altered because of the first surgery. There may be scar tissue that makes it hard for a surgeon to see what he’s doing, what he’s encountering, or may be confusing as to what the normal anatomy is.