A Brief History of Trepanation, One of the World’s Oldest Surgeries

In the 1860s, a U.S. newspaper editor, author, and amateur archaeologist named E.G. Squier traveled to Cuzco, Peru. He visited the home of a wealthy woman who collected antiquities to view an ancient skull, discovered in an Inca cemetery in the Valley of Yuca and dating to pre-Columbian times. Notably, it had a large, rectangular hole at its top.

Squier—a well-educated polymath whose areas of expertise also included Latin American culture—was immediately intrigued. He brought the skull to New York in 1865 and presented it to members of the New York Academy of Medicine.

Squier believed that the skull was clear evidence that Peru’s ancient people had performed brain surgery. The hole’s cross-hatched outlines were the work of a human hand; Squier noted that they were most likely made with a burin, a tool used by engravers on wood and metal. Even more shockingly, he observed, the skull showed signs of healing—meaning the patient had survived the procedure for at least one to two weeks before they died.

Members of the medical community were skeptical that the cuts were made prior to death. Squier sought the opinion of renowned French surgeon and anthropologist Paul Broca, who examined the skull and concluded that Indigenous societies had been performing “advanced surgery” long before Europeans arrived.

It was surprisingly sophisticated Stone Age surgery.
Physicians developed trepanation tools and techniques.
Trepanation was probably performed without anesthesia.

It was surprisingly sophisticated Stone Age surgery.

Trepanation is the practice of drilling or scraping a hole into the skull’s cranial vault to expose brain tissue and treat injuries. First mentioned by the Hippocratic Corpus, it’s one of the world’s oldest surgeries (the word trepanation comes from Greek and means “auger” or “borer”). Today’s medical community refers to it as a craniotomy.

Throughout history, trepanation has been practiced in nearly every part of the world. It was performed in ancient Greece and Rome, and reportedly is used in parts of Africa, South America, and the South Pacific even today. In ancient Greece, doctors performed trepanation to relieve pressure, remove skull fragments from the brain after a traumatic accident, and drain fluid. From the Renaissance until the beginning of the 19th century, trepanation was routinely used to treat head wounds, and into the 18th century, it was used to treat epilepsy and mental disorders.

Western physicians of Squier and Broca’s time thought it unlikely that non-European cultures throughout history may have attempted the procedure. Since survival rates from the surgeries performed in the 19th century were so poor due to hospital-acquired infections, they doubted that ancient patients could have lived for long following the operation.

After Broca acknowledged Squier’s find, however, scientists began discovering trepanned skulls across the globe, dating back to the Neolithic period. Hole-drilled heads were found in Western Europe and the Americas. Over the years, it became clear that many societies across the globe had attempted trepanation, starting in the late Paleolithic period at least 10,000 years ago.

Physicians developed trepanation tools and techniques.

Surgical techniques varied from culture to culture. Prehistoric trepanations performed in early Peru were done with a ceremonial knife called a tumi, which was used to scrape or cut through the bone. The Hippocratic school invented the trephine drill, which bored holes into the skull. In the South Pacific, they used sharpened seashells to cut bone; in Europe, flint and obsidian. By the Renaissance, physicians routinely performed trepanations with specially developed instruments.

Trepanation was performed on young and old, male and female. According to research by the cognitive neuroscientist Charles Gross, estimates for survival range from 50 to 90 percent and some prehistoric patients had lived for years after the surgery. In many cases, though, the pathology that necessitated the procedure remains unclear.

John Verano, an anthropologist at Tulane University who studies trepanation in Peru, told Mental Floss in 2016 he's convinced that “in Peru, the South Pacific, and many other parts of the world, trepanation began as a very practical treatment for head injuries. Say somebody has a head wound that’s torn up their skull. You’d clean it out and remove little broken fragments and allow the brain to swell a little bit, which it does after injuries.”

In some instances, trepanned skulls show clear evidence of trauma—meaning there must have been an underlying reason why the procedure was performed. However, archaeologists have also uncovered trepanned skulls that don’t show depressed fractures. Squier's famous skull, for instance, didn't indicate any signs of a head wound. Skulls with multiple holes have also been unearthed, revealing that patients likely had—and survived—more than one surgery.

Modern eyewitness accounts from Africa and the South Pacific state that trepanation is still used to treat head wounds, headaches, or pressure on the brain, Verano said. In other parts of the world, it’s thought that trepanation might have once been used to release evil spirits, or to treat mental illness or epilepsy. But without any written record, we’ll never know exactly why these kinds of surgeries were performed in the absence of obvious injury.

Trepanation was probably performed without anesthesia.

Patients may have been unconscious during the surgery if they had suffered a head wound, Verano said. Otherwise, they would have been awake. “The scalp has a lot of nerves, so it hurts to cut your scalp,” he said. “It also bleeds a lot, but then it stops. But the skull has very few nerves, and the brain has no nerves.” Plus, ancient surgeons weren’t cutting through the brain’s dura mater, the outermost layer of three protective membranes covering the brain. (If they had, the patients would have developed meningitis and died.)

In modern hospitals, trepanation is no longer viewed as its own curative procedure. Surgeons perform craniotomies to remove dead or infected tissue from wounds, relieve pressure in the skull, or perform exploratory surgery. It’s fascinating to realize that this technique survived many millennia—and that in prehistoric times, humans understood that the brain controlled the body.

Additional Sources: A Hole in the Head; Trepanation: HIstory, Discovery, Theory

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A version of this story was published in 2016; it has been updated for 2025.