UC Santa Barbara bioarchaeologist Danielle Kurin and her archaeological team unearthed the remains of individuals from burial caves in the Andean province of Andahuaylas in south-central Peru that date to the Wari empire between AD 1000-1250. Among the 32 crania of these remains, researchers found evidence of 45 trepanation procedures that show how prehistoric Peruvian practitioners experimented with trepanation methods, which include scraping, cutting and hand drills. Trepanation is an ancient surgical procedure that involves removing a piece of the cranium and was used to treat a variety medical issues from head trauma to mental illness.
Bioarchaeologists can ascertain whether or not a patient survived a trepanation procedure by the presence of smooth, rounded bone growth around the incision. So Kurin was able to tell assess the survival rate of each technique by the presence of new bony growth. She found that scraping trepanations were the most successful, while drilling, cutting, and circular grooving had lower survival rates. Kurin argues that Wari healers were also practicing different trepanation methods on deceased individuals.
Kurin tells Phys.org, “It looks like they were trying different techniques, the same way we might try new medical procedures today. They’re experimenting with different ways of cutting into the skull…The idea with this surgery is to go all the way through the bone, but not touch the brain. That takes incredible skill and practice.”
Kurin says, “As bioarchaeologists, we can tell that they’re experimenting on recently dead bodies because we can measure the location and depths of the holes they’re drilling. In one example, each hole is drilled a little deeper than the last. So you can imagine a guy in his prehistoric Peruvian medical school practicing with his hand drill to know how many times he needs to turn it to nimbly and accurately penetrate the thickness of a skull.”