The problem that The Retrievals deals with is epidurals failing during cesarians, which, they're quick to emphasize, is painful, open abdominal surgery. The not-so-simple solution is to convert to general anesthesia (anesthetic gas, IV propofol, etc). This isn't without its risks to the mother and the child, so there's reluctance on the part of anesthesiologists to go that route if there's other options. The result is unnecessary birth trauma.