Thursday, August 21, 2014

"Partial Autopsies Yield Partial Answers"

"Partial autopsies yield partial answers" Dr. Charles Hirsch taught me as a young doctor during my forensic pathology fellowship training in New York City, in 2001-2003. This was one of scores of aphorisms we called "Hirschisms," which he employed to instruct us about forensic pathology. Another one was, "Don't confuse the autopsy with the death investigation."

Both come to mind this week in the wake of the release of the findings of the second Michael Brown autopsy, conducted by Shawn Parcells and Dr. Michael Baden. The body diagram they released to the press in the New York Times has now been altered into the "Hands up! Don't Shoot!" pose and is trending on Twitter.

The wounds are clustered closer together, so it must be "realistic," right? 

No. 

This is click bait—a picture that you can retweet easily without thinking about it much. This "tweaked" diagram is a grossly inaccurate portrayal of the victim's body position. The horizontal graze wound near the elbow is missing entirely; the top of the head wound doesn't make sense unless the victim is leaning forward; and the diagnonal graze wound on the right thumb would not occur if the right hand were up in this way—the graze wound has to be in line with the gun barrel, which means the hand was possibly extended forward toward the officer. That's assuming you trust the diagram.

And that's where my experience as a forensic pathologist and death investigator makes me ask a few questions:

1. Why was this diagram from the second autopsy—this evidence of the wounds on the body—even released to the public? The original autopsy diagram, the one prepared during the first autopsy by the St. Louis County medical examiner's office, is still sealed. So are the photos, scene data, and other evidence the district attorney will rely on to decide whether to prosecute the police officer. In all homicide cases, evidence such as this diagram is kept sealed so as to not influence potential witnesses who might see it in the press and change their testimony. Why release crucial evidence that could scuttle that prosecution? 

2. How reliable is this diagram? As I wrote in my recent OpEd on CNN.com, gunshot wound interpretation is not always easy. Parcells and Baden have opined that there were "at least 6 gunshots"—but without knowing the number of rounds fired, the number of casings and bullets recovered, the condition and location of those bullets, and the possible witnessed positions the victim was in, how can they say that with any certainty? What if the same bullet grazed the thumb and then re-entered the body, causing another wound? This diagram alone doesn't tell the whole story.



The diagram reproduced in the New York Times and elsewhere has both Parcell and Baden's signatures at the bottom—but which one of them made the diagram? And why are there no other details about the individual wounds on it? Why have they not noted the location from the top of the head/right of midline, wound size and shape? Where are their notes about soot, or stippling, or other trauma besides the gunshot wounds? The body diagrams I prepare during the course of a forensic autopsy are a whole lot more detailed than this; I need those details in order to accurately dictate my report after I finish the autopsy and get out of the morgue.

3. How reliable is the second autopsy?
There have been recent reports in the press that forensic technician Parcells has no credentials or accreditation, and misrepresents his experience.  Following allegations that Parcells did the autopsy alone, a doctor/blogger in PathologyBlawg.com interviewed Parcells. Parcells affirmed that he alone examined the body on 8/15 before it was embalmed; Dr. Baden was not yet in Missouri at that time. Two days later, after the body had been embalmed, Dr. Baden performed the second autopsy.

There is a big difference between the examination of Michael Brown's undisturbed body during the first, legally-mandated autopsy, performed by the St. Louis medical examiner, and the follow-up examination done days later on his washed and embalmed cadaver. In the embalming process, preservative fluids are injected into the arteries and organs using a sharp tool called a trocar. The trocar pokes holes in the organs. The preservative fluid in the blood vessels pushes the blood ahead of it to the site of any injuries. These changes, which we call "embalming artifact," can exaggerate the size and shape of injuries. 

Even if Dr. Baden, a board-certified forensic pathologist, looked at photos of the injuries taken prior to the embalming, the orientation and quality of the photos taken by the technician would influence his interpretation of the findings. Autopsy means "see for yourself"—and there is no substitute for seeing the undisturbed body for yourself if you are going to be offering opinions with legal ramifications.