I've heard of trepanation. What is it?

Trepanation is an intriguing procedure that has been practiced for several thousand years. Basically, trepanation is the process of removing part of the skull for a variety of real or imagined benefits. The procedure, or variants of it, is still done today, but no, doctors aren’t drilling into the skull to release evil spirits. Dubbed a craniotomy or craniectomy depending on whether or not the removed bone is replaced, the intent is to reduce pressure on the brain for people who have experienced severe head trauma. Modern trepanation isn’t as uncommon as you’d think.

Of course, there are those who claim that trepanation also has all manner of spiritual benefits. Tales of increased energy, improved creativity or permanent highs, have convinced some people to undertake trepanation in their own homes using drills or carpentry equipment. In a fascinating, if gory, article, a body modification affectionado named Bryan Henderson explains his experiences with the procedure.

http://www.bmezine.com/news/people/A10101/trepan/

As much as I hate to even have to say this, please don’t try to open your skull at home. Henderson himself admits that any positive changes he experienced were short-lived and mostly due to wishful thinking. The stupidity of drilling holes in your head for unrealized benefits really can’t be understated.

That said, as I mentioned earlier, trepanation has been practiced around the world for millenia. Some of the best documented cases come from the Andes Mountains where, at some archaeological sites, skulls have been found that are riddled with holes. What’s particularly intriguing is that the survival rate seems to have been fairly high for operations. You can tell by looking at signs of healing that some individuals lived for longer periods than one would expect. This is especially surprising considering that the openings were made by sawing or scraping into the skull with stone tools. These unusual survival rates are still not meant to be an endorsement. Please don’t cut your skull!

In archaeology, however, not all holes in skulls are trepanations. In any society with warfare, there will likely be a number of head injuries that look like intentional trepanations that are more likely to simply be battle wounds. In the pictures below for example, the hole in the upper individual’s skull is probably the result of a glancing sword blow. This can be inferred from the large number of skulls from the same area that look like the one shown in the second image. The massive piece of bone missing from the face was obviously not intentional.

Interestingly, the upper individual clearly lived for a few weeks following the injury. Look at the difference in the porosity of the bone immediately surrounding the cuts in both images. The fact that the bone surrounding the cut on the upper skull looks much less spongy than the lower one is evidence of healing. That it isn’t completely smooth, however, indicates that the person died before healing fully.