Brainy Bondage

Last week, we discussed the fantastical flexibility of the newborn’s skull and how cultures around the world have taken advantage of its malleability by intentionally modifying it into strange and mesmerizing shapes.

This week, however, we are exploring the opposite end of the spectrum: what happens when your brain is locked inside a box that cannot yield. Let me tell you up front – it ain’t good. 

By the time a child is around three years of age, the fontanels, or soft spots that reside between the
plates of the skull, have vanished as the sutures joining the plates fused. Those sutures will continue to meld throughout your lifetime and if you live long enough, may completely disappear (what we in the skeletal biz call “obliterate”).  

But having a network of fused plates encasing that most essential organ, the brain, is a double-edged sword. Let’s discuss the pros and cons of this brainy box. 

The skull offers protection to the delicate tissues that compose the brain. Without the skull, you’d most likely suffer brain damage before lunchtime, for without the protective cover of the cranium, all it would take is a subtle knock on the noggin to cause permanent damage. There’s a reason all vertebrates sport a helmet at the northernmost region of their spinal apparatus. Whether you’re a tiger or a toad, an elephant or an anteater, protection is a must and the cranium does a pretty fair job of buffering our brains. 

But even with a skull, damage happens. A trip and a fall or a crash on your bike is all it takes to cause a head injury and one of the scariest injuries you can suffer is closed head trauma. 

Closed head trauma is just as it sounds: the brain is damaged even though the skull is intact. The reason these types of injuries are so serious is that the brain, like any other soft tissue in the body, tends to bleed and swell when damaged. And whether the brain bleeds, swells, or both, there’s no place for any of it to go. It is entrapped within an unyielding bony container and without immediate intervention, the pressure intensifies, neurochemicals are released, causing further damage, and basic functions (like breathing and heart rate) are stifled as the brainstem is choked off.

So what’s a neurologist to do?? There are drugs to reduce the swelling, which are usually the first line of treatment, but if the swelling persists, they must take further action.

Rev up the bone saw; it’s time to make a window. 

Craniotomy is just as daunting as it sounds. A flap of bone is removed, which allows a bit of breathing room for the swollen brain. The piece of bone is usually popped in the freezer so that, when the brain stops swelling and returns to normal, the bony patch can be replaced and the patient restored (one hopes) to normal function, or at least something close. 

The most amazing aspect of craniotomy is that folks have been performing it long before modern medicine came on the scene. It turns out we’ve been cutting into each other’s skulls for thousands of years. 

"Trepanning" is from the Greek, meaning to "bore" or "auger," which is most appropriate, since practitioners over seven thousand years ago were drilling into the heads of their friends and neighbors. Also known as "trephination," the procedure was originally accomplished using flint scrapers, knives and even shell; that is until the advent of metallurgy. Obsidian blades were also effective, as were bow drills. We can sometimes determine the tool used by the evidence left on the skull. A round hole with beveled edges? Probably scraped. Square hole with straight lines? Probably a blade. A beautiful little circle? Bet on a drill. Not only can we decipher the tool used, but by noting healing (remodeling) to the periphery of the wounds, we can also determine if the individual survived the procedure, which, surprisingly, many did.

The ancients may have been trepanning for some of the same reasons we perform craniotomies, since some of the skulls show evidence of traumatic injury. Was trepanation done solely for medical reasons? Probably not. There may have been a ceremonial component to it, perhaps to release bad spirits or correct psychotic behavior. Perhaps it was to obtain bone amulets, since it was performed on the dead as well as the living and nothing says "fashion" like sporting a bit of cranial bling. 

Whatever the reason, we know that people around the world for thousands of years were dabbling in neurosurgery long before there were neurosurgeons. Just as early explorers wondered what lay beyond the horizon, the human body also afforded a landscape worth exploring. And what better place to start than a hole in the head?

Here's a short video on trepanned Peruvian skulls.

Have a great week and I'll catch you next Friday.