A Precise and Practical Surgery

Unlike their European contemporaries, who often punctured the brain’s protective membrane and caused fatal infections, Inca healers developed techniques that minimized damage and maximized survival. In fact, Inca skull surgeries had survival rates as high as 80% in some periods—centuries before antisepsis and anesthesia were introduced in Europe.

The surgeons responsible for these procedures were known as “Hampicamayoc” (from hampi, meaning “medicine” or “healing,” and camayoc, “specialist”). They performed trepanations with a variety of tools and techniques, carefully adapted to each case. Evidence from skeletal remains shows multiple methods: scraping, cutting, and drilling. These were not crude operations; surgeons were careful to avoid penetrating the dura mater—the membrane protecting the brain—thus reducing the risk of fatal infections.

Trepanation techniques varied depending on the severity and location of the head injury. The Hampicamayoc used scraping, drilling, and cutting methods, each adapted for different medical situations. The most common tool was made of obsidian or other sharp stones, with some procedures also using bone scrapers.

Though rudimentary by modern standards, these tools were effective. Incisions were made with precision and restraint, avoiding unnecessary trauma. Multiple trepanations on a single skull—some of which showed signs of healing—suggest that patients sometimes underwent more than one procedure and survived.

Remarkably, some skulls show signs of healing after surgery, indicating long-term survival. In some cases, bone regrowth around the surgical site provides evidence of recovery lasting months or even years. 

Some skulls display multiple trepanations—evidence that individuals underwent more than one procedure. The survival rate and frequency of these operations suggest not only surgical skill but also a societal structure that supported medical training, recovery, and long-term care.

A major contributor to this difference was the importance they gave to clean environments and their knowledge in the use of antiseptic substances, including plant extracts that modern science now recognizes for their antibacterial properties. For instance, they used hierba santa (Cestrum auriculatum) as an antiseptic, anti-fever agent, and sedative; paiko(Chenopodium ambrosioides) for its healing and calming effects; and thyme (thymus vulgaris) to stimulate cerebral circulation. Valerian and condor blood were used to prevent convulsive crises, while highly fermented corn chicha and infusions made with mushrooms (miyu Kallampa) and Chamiko (dutura stramonium) served as early forms of anesthesia. These remedies reflect a sophisticated understanding of pharmacology, long before the development of modern medicine.

Trepanation was not unique to the Inca. Archaeological evidence shows that skull surgery was performed in the Andes by pre-Inca cultures before the rise of the empire. However, it was under Inca rule (ca. 1400s–1530s) that the practice became widespread and increasingly sophisticated. More than 800 trepanned skulls have been found across Peru and Bolivia, the majority from Inca and pre-Inca sites, making it the highest number recorded anywhere in the world.

Why Did They Do It?

There are several theories as to why trepanation was practiced. The most accepted is that it was used to treat head injuries, particularly from warfare or accidents. Many skulls show fractures near the site of trepanation, supporting this idea. Others suggest that the procedure was performed to relieve pressure from swelling or to treat neurological disorders like epilepsy.

A third theory points to a more spiritual motivation. In Andean cosmology, illnesses were often linked to spiritual imbalances or malevolent forces. Opening the skull could have been a symbolic act to release these harmful spirits or realign the patient’s inner world with the cosmos. Whether the motivation was physical or spiritual—or both—the procedure reflected a holistic understanding of health, body, and soul.

A Gifted Skull

In 1865, Ephraim George Squier, an American explorer, archaeologist, and ethnologist, was in Cuzco when he was gifted a remarkable object: a trepanned Inca skull. The gift came from Señora Zentino, a local woman whose family had preserved the artifact. The skull bore a clean, square opening, with clear signs of healing—evidence of a successful surgery.

Squier sent the skull to the New York Academy of Medicine, it did not raise the attention and interest it deserved as the scientific community refused to believe that anyone could have survived a trephining operation carried out by a Peruvian Indian. He later presented the skull to Paul Broca, professor of external pathology and of clinical surgery at the University of Paris and founder of the first anthropological society. Broca concluded was that it was indeed a case of trepanation and the patient had survived for some time. Howeveer, when Broca presented these findings to the Anthropological Society of Paris in 1876, the audience, like their counterparts in the United States, refused to recognize that indigenous people could have carried out such complex surgical procedure successfully. In time that skull—and others like it—were re-examined using more advanced techniques such as CT scans, helping transform how scholars understood the complexity and sophistication of pre-Columbian science and medical practices.

Strategic Innovators

While trepanation was practiced in other ancient societies—including ancient Greece, Egypt, and Polynesia—no civilization matched the Incas in frequency or success rate. Their highland environment, war-driven society, and emphasis on practical healing likely converged to foster medical innovation.

Importantly, the Inca approach emphasized adapting treatment to the condition. Hampicamayoc chose different methods depending on whether the injury was caused by blunt force trauma, penetrating wounds, or other causes. The procedures were not random acts of desperation but deliberate, skillful responses to injury.

Moreover, the Incas understood the value of preserving life rather than simply experimenting. They practiced a form of evidence-based surgery, learning from past procedures and improving over time.

Some of this success may be attributed to the highland climate, which naturally inhibits bacterial growth, but it’s clear that technique and knowledge played a greater role. The Hampicamayoc were part of a sophisticated medical tradition that blended observation, empirical learning, and a deep understanding of both body and nature.

Invaluable Legacy 

The achievements of the Inca in medicine are only beginning to receive the recognition they deserve. While much attention has been given to Machu Picchu and Inca road systems, the survival rate and precision of Inca trepanation offer compelling evidence of scientific innovation 

Modern medicine owes much to the accumulated knowledge of early surgical pioneers, and the Inca example stands out as one of the most advanced pre-modern medical systems. Their achievements challenge Eurocentric narratives about medical history and emphasize the value of indigenous knowledge systems.

The Inca approach to skull surgery—its careful technique, high success rate, and cultural integration—offers not only a glimpse into the past but a lesson in holistic medical practice. While today’s neurosurgeons rely on machines and precision tools, the principles guiding them remain surprisingly consistent with those practiced in the Andes centuries ago.

References

-Pre y Postoperatorio en la trapanaciones Incas
https://aanc.org.ar/ranc/items/show/375

-Holes in the Head
https://phys.org/news/2018-06-holes.html

-A Hole in the Head: A History of Trepanation
https://thereader.mitpress.mit.edu/hole-in-the-head-trepanation/

-Inca Neurosurgery: Challenging Western Medical Narratives
https://www.peruviantimes.com/28/ancient-inca-neurosurgery-challenging-western-medical-narratives/32492/