Written by: Katy Meyers Emery
Primary Source: Bones Don’t Lie, December 3, 2015.
Let’s just say that you are an Iron Age herder living in Switzerland. You’re out walking through your flock of cattle, and one of them gets fiesty and kicks you in the head. Ouch. Over the next couple days, a pressure builds in your head and becomes unbearable. The elders in your village discuss the situation, and decide that the only option to release the pressure is trepanation. That’s right. They are going to drill a hole into your head. What is your chance of survival? 78%. How do we know that? Let’s get some background first…
Four methods of trepanation via DigVentures
We’ve talked quite a bit about trepanation, defined by Erdal and Erdal (2011) as the “removal of a bone piece of the skull of a living individual without penetration of the underlying soft tissue”. Brothwell (1981) identified three common methods of removing the bone throughout history, including: 1) drilling small holes in a circular pattern which will connect and allow for removal of a section, and produces a circular pattern of smaller circles; 2) scraping away in a circular pattern until the inner table is penetrated, which creates a more clean circular pattern; and 3) sawing at the bone in long canoe shaped lines to create a rectangular pattern, which leaves a rectangular hole in the skull. Erdal and Erdal (2011) examined these types of lesions throughout Anatolia’s history, and found that the highest rate of survival was among those who recevied the second scraping method, and the lowest rate was for those receiving the third rectangular method.
A new study by Moghaddam et al. (2015) examines the procedure of trepanation throughout Switzerland’s history, specifically looking at the survival rates of different ages and sexes, and how these change over time. They examined 34 individuals with 43 cases of trepanation spanning from the Neolithic to Pre-Modern times from a variety of regions throughout the country. For each individual, they looked at the age and sex of the individual, where the trepanation was located, the timing of the surgery whether during life (intra vitam), pre, peri or post-mortem (before, during or after death), or whether it couldn’t be determined, and finally, what the survival rate of the individual was.
Example of trepanned skull from Neolithic Switzerland, via Wikimedia Commons
During the Neolithic, there were 10 individuals with evidence of trepanation, with an even spread over whether the hole was drilled into the occipital (back of the head) or parietal (side of the head) bone. There was a 72% survival rate during this period, and 50% of the individuals had the surgery performed during their lifetime with clear evidence of healing. In the Bronze Age, only one surgery was performed post-morten and the other was performed during life, indicating a 100% survival rate. Both from this period were located in the frontal bone (front of the skull). During the Iron Age, there were also ten individuals with trepanations. Of those, 60% were performed during life with strong evidence of healing, and there was a 78% survival rate for the procedure. The majority of these were located on the frontal or parietal bone.
Interestingly, it isn’t until the early medieval period that survival rate declines. Of nine individuals, only half survive their trepanation and only three were performed during life with evidence for major healing. These range in location including the frontal, parietal and occipital bone. Only one individual from the Middle Ages was identified, and they did not survive their trepanation to the parietal, and the single individual from pre-modern times survived three trepanations but not the fourth (seriously… you survive three and the last kills you… yikes!).
What we learn from this study is that you actually had a fairly high chance of surviving a trepanation in prehistoric Switzerland- it isn’t until medieval times that you actually need to worry about it! Moghaddam et al. (2015) argue that this probably indicates that Neurosurgery was an early specialization, and that ancient populations had a better understanding of the body and healing processes than we often attribute them with. Sure, they may have thought the pressure in your head was due to spirits or demons… but you’d probably survive the procedure!
Want to learn more? Check out my other posts on trepanation and some by other authors!
Trepanation: A How-To Guide by DigVentures
Holey Cranium Batman! Archaeology of Trephination by GraecoMuse
Trepanation [Podcast] by Sawbones
Trepanation for Tibial Surgery in Peru by Bones Don’t Lie
Symbolic Scraping: Trepanation in Hungary by Bones Don’t Lie
Erdal, Y., & Erdal, �. (2011). A review of trepanations in Anatolia with new cases International Journal of Osteoarchaeology, 21 (5), 505-534 DOI: 10.1002/oa.1154
Moghaddam, N., Mailler-Burch, S., Kara, L., Kanz, F., Jackowski, C., & Lösch, S. (2015). Survival after trepanation—Early cranial surgery from Late Iron Age Switzerland International Journal of Paleopathology, 11, 56-65 DOI: 10.1016/j.ijpp.2015.08.002