When people say “I need that like a hole in the head,” it means they don’t want whatever’s up for discussion. Even with the advances of modern medicine, cranial surgery is still extremely invasive—which makes it all the more surprising that people who had this surgery during the Inca Empire had a fairly low mortality rate.
For thousands of years, people around the world have used trepanation surgery (i.e., cutting a hole in the cranium) to address head trauma and other ailments. During the American Civil War, the mortality rate for trepanation was between 46 and 56 percent. But centuries earlier, the mortality rate for this procedure in the Inca Empire was 17 to 25 percent, according to a study published in the March 2018 issue of World Neurosurgery.
The study looked at over 800 skulls that had undergone the procedure between roughly 400 B.C.E. and C.E. 1500. The skulls show a clear improvement in cranial surgery among the coastal regions and the Andean highlands of Peru, leading up to a high survival rate in the 15th- and 16th-century Inca Empire.
The study’s authors determined if a person had died shortly after surgery by looking at whether his or her skull had had time to heal. However, researchers aren’t sure what specific medical practices contributed to high success rates. Good hygiene might have played a factor, since bad hygiene contributed to high rates of wound infection during the Civil War.
During the Civil War, “if there was an opening in the skull they would poke a finger into the wound and feel around, exploring for clots and bone fragments,” said David S. Kushner, a medical professor at the University of Miami and lead author of the recent study, according to a university press release.
“We do not know how the ancient Peruvians prevented infection, but it seems that they did a good job of it,” he continued. “Neither do we know what they used as anesthesia, but since there were so many [cranial surgeries] they must have used something—possibly coca leaves. Maybe there was something else, maybe a fermented beverage. There are no written records, so we just don’t know.”
Though the Civil War helped establish anesthesia as a standard medical practice in the U.S., most doctors weren’t familiar with it when the war began in 1861. American physicians had only been using anesthesia since the 1840s and 1850s, and doctors weren’t always sure that chloroform, the most popular form of anesthesia, was safe.
But whatever medical standards Inca doctors used, it’s clear that they and their Peruvian predecessors were on the cutting edge.
“They seemed to understand head anatomy and purposefully avoided the areas where there would be more bleeding,” Kushner said. “They also realized that larger-sized trepanations were less likely to be as successful as smaller ones. Physical evidence definitely shows that these ancient surgeons refined the procedure over time. Their success is truly remarkable.”