Getting an autopsy isn't like taking your car to the garage. If a mechanic takes the steering wheel apart, he can put it back together exactly as he found it. Obviously, when a dead person's ribs have been cut, they can never be uncut.
Right off the bat, conducting a second — or third — autopsy on a body that's already been dissected presents significant challenges. Fluids extracted from the cadaver during the first examination are not always preserved for later study. Likewise, the opening and reshuffling of organs can leave the second pathologist with something of a jigsaw puzzle. Photographs of the body taken before or during the original autopsy are extremely helpful in these situations. So are the accompanying notes.
Despite all the hurdles, skilled pathologists may be able to oblige families or investigators who want repeat autopsies. New evidence sometimes emerges during follow-up postmortems. Maybe the second autopsy will involve molecular-level dissections that weren't performed during the first. Or perhaps it will take a closer look at an underexplored portion of the body. By comparing new findings with information from the previous autopsy, investigators might get a clearer picture of the circumstances surrounding a person's death.
Yet experts say that even when sequel autopsies turn up fresh clues, they rarely undermine the overall conclusions drawn from the first postmortem — unless that initial procedure was botched. Nonetheless, a second go-around can be a means of quality control. It may also provide reassurances to the decedent's loved ones.