Safest routes for a projectile through the human head?

January 6, 2014 12:48 PM

Phineas Gage was famous for "his improbable survival of an accident in which a large iron rod was driven completely through his head". How many different ways (depths, angles) could you safely pass such an object through the human head without complete loss of brain function / death?

I imagine the question is complicated by how different sizes and shapes of objects, at varying speeds, will create a variety of entry and exit trauma. To simplify matters, let the "projectile" be an idealized kind of drill, with as large or small a radius as we want, that might pass through some portion of an adult human head, removing only the material in the path of the drill, leaving the surrounding tissue more or less intact.

What I'm curious to know is, how *much* of the head could you pass such a drill through without irrevocably harming someone? I realize "irrevocable harm" is ambiguous, and brain damage has a wide range of possible effects on a person, so if it makes the question any clearer, we could consider death to be the cutoff for viable trajectories.

It seems like the frontal cortex is pretty robust (as demonstrated by Mr. Gage above), but I imagine the hind brain is much more sensitive to damage. Which trajectories are safest and/or most dangerous? Could you pass something from ear to ear? From the forehead out the back?

I would be especially interested in medical literature and case studies, where possible.

posted by grog to Science & Nature (10 answers total)

Ahad Israfil was shot in the head and lost most of a cerebral hemisphere and nearly half his skull. He survived and regained most of his faculties; the worst effect is that now he needs a wheelchair. No indication of what the bullet's trajectory was, but you can get an approximate sense from the photo.

So - more or less in the forehead and out the back, though not dead center. This was more off to the side.
posted by FAMOUS MONSTER at 12:59 PM on January 6, 2014

Famous Monster beat me to the Ahad Israfil link - dang! Yeah, any route that sticks exclusively to ONE hemisphere - no corpus callosum, no cerebellum - is gonna be the best possible bet. So imagine the brain as a bisected superball, glued back together, with a fava bean attached to the lower back side of it: avoid the glue, avoid the bean.
posted by julthumbscrew at 1:02 PM on January 6, 2014 [1 favorite]

Best answer: You'll definitely want to read up on lobotomy!
posted by showbiz_liz at 1:03 PM on January 6, 2014

There's also the case of Anatoli Bugorski, who was shot in the head with a beam from a particle accelerator. It went in the front and out the back. He survived. Again, damage to one hemisphere only.
posted by FAMOUS MONSTER at 1:05 PM on January 6, 2014 [2 favorites]

A cursory search isn't finding a clip of it but I remember watching an "Amazing but true!" type television show that described several cases of such injuries. The two I remember were:

• A twelve-year-old boy who had fallen off his bicycle face-first into some sort of farm vehicle, and ended up with his head impaled on a thin, rusting metal spike sort of like a long nail that went in through the center of his forehead and almost all the way through his brain, right between the hemispheres
• A British man who, while playing pool, tripped and fell into a rack of pool cues and somehow ended up with one of them going diagonally in through the bottom of his jaw, through the top of his mouth, behind his eyes, and I can't remember if it was protruding from the top of his head. He evidently remained conscious the whole time and there was a photograph or a short video clip of him sitting in a chair before the paramedics had shown up.

posted by XMLicious at 1:12 PM on January 6, 2014

There's way too many possible variables. Does the subject have immediate access to level 4 trauma facilities? Are we assuming the best quality doctors working at their best? Does someone dependent on life-support count as long as they still have brain activity?

Yes, if the damage is limited to one hemisphere then you can usually recover with some emotional/personality problems but more or less function "normally".

As for survivability period, I'm no expert but I believe that as long as the brain stem is intact and intracranial pressure is ok and bleeding is controlled, you can live (and I mean live in the barest sense of the word) on life support for however long the family wants to deal with it.

The velocity of the projectile is as important as the direction and more important than the size. Gunshot wounds to the brain usually result in death because the shock of the brain trying to absorb the projectile's kinetic energy results in severe tissue disruption throughout the brain, followed by heavy bleeding and probably high intracranial pressure if there is no exit wound and low pressure if there is one.

More people than you would probably think survive self-inflicted gunshot wounds to the head. Even with shotguns. In the case of shotguns, usually they put the barrel under their chin but angle it wrong so that it blows their face off but doesn't penetrate their skull (yes these people do live). In the case of handgun wounds I think this is the best study:

Abstract

A consecutive series of 67 patients who had sustained self-inflicted gunshot wounds of the brain was reviewed retrospectively to evaluate factors determining outcome. Weapon caliber, site of bullet entry, degree of brain wounding on computerized tomographic scan, and presenting Glasgow Coma Scale (GCS) score were examined. Overall mortality, degree of disability in survivors, and survival time after injury in fatally wounded patients were assessed. Ninety-eight percent of all patients with an initial GCS score of 8 or less died. When the GCS score was more than 8, 91% of patients survived (P less than .0001). Survival rate was significantly increased in patients with injury limited to one lobe of the brain, compared with patients with brain wounds of greater severity demonstrated on computerized tomographic scan (P less than .05), while a missile crossing both vertical anatomic planes of the brain or coming to rest in the posterior fossa was lethal in 100% of cases. Survivors scored relatively well on the Glasgow Outcome Scale. Almost all (98%) fatally injured patients maintained vital functions for a time ample for transportation and evaluation at a major referral center. These findings hold important implications for trauma center and critical care resource allocation as well as organ transplantation programs.

I recently watched a great lecture online by an expert in this field but I'm momentarily forgetting what it was called. I'll post the link when I can find it.
posted by WhitenoisE at 1:21 PM on January 6, 2014 [1 favorite]

If death is the only criteria, the brain stem is essential for life, while the rest of the brain is arguably dispensable...
posted by kisch mokusch at 1:33 PM on January 6, 2014

Not a direct answer to your question, but if this sortof thing interests you, the delightful TV show "I Was Impaled" (link goes to NY Times review of the first episode) included several people with objects lodged in their heads, among other body parts.
posted by goshling at 5:46 PM on January 6, 2014

Best answer: I was going to say the same thing as kisch. The are many possible trajectories as long as you don't hit the brain stem. Losing the corpus callosum doesn't kill you, in fact, severing the corpus callosum is a radical treatment for refractory epilepsy. Other parts of the brain that mainly control things like speech and motor function are routinely lost by stroke patients without causing death. Also consider the fact that there have been rare cases of infants with anencephaly who survive for years. The human brain has a property called plasticity that helps it to recover after trauma. The people impaled by your theoretical drill will do better than real life trauma patients. Many of these patients are killed by intracranial bleeding and complications from that (brain swelling, increased intracranial pressure, etc) rather than the tissue damage caused by the projectile going through their head. That's a rather disjointed reply but I hope it is useful.
posted by treehorn+bunny at 6:01 PM on January 6, 2014

Hemispherectomy. It's a thing. While parts of the brain aren't strictly redundant, function is pretty widely distributed, in a broad sense, and the brain is pretty plastic. Localized brain injury is rarely fatal completely on its own, as long as areas that sustain basic life processes are unaffected. Brain surgery patients have undergone some pretty radical procedures without dying.
posted by Nomyte at 11:51 PM on January 6, 2014