The Ancient Practice of Trepanation: Drilling Holes in the Skull for Medical Reasons

If you had to guess, which surgical procedure would you consider the oldest? Perhaps a Caesarean section? Amputation? Appendectomy? It might seem unusual, but the surgery that humans have been performing since the Neolithic era is trepanation (also known as trephination or trephining)—the practice of drilling a hole into the skull to address intracranial health issues, relieve pressure from a head injury, or even to allow evil spirits to escape.

Ancient Holes in the Skull

While you might not be keen on having a caveman perform brain surgery on you, it's fascinating to note that this practice was actually quite popular in its time.

"Over 1,500 skulls showing signs of trepanation have been uncovered across the world, from Europe and Scandinavia to North Africa, and from Russia and China to the Americas — especially in Peru," says Dr. Miguel Faria, a medical historian and retired neurosurgery professor at Mercer University School of Medicine in Macon, Georgia, via email. "The densest concentrations appear to be in Eurasia and South America."

This procedure wasn’t just widespread; it seems drilling holes in skulls was all the rage during the late Neolithic period, between 4,000 and 12,000 years ago. In fact, if you examine skulls from this era found globally, 5 to 10 percent of them bear holes made while the person was alive. Most of these skulls belonged to men, though women and children were also subjected to the procedure. The holes were intentional, and some of the individuals survived the operation — at least for a while.

The burning question remains: why?

Healing Through Holes

According to Faria, while we can't truly know the intent of ancient medical practitioners, trepanation likely served as a remedy for various conditions—possibly performed by shamans to "heal" or alter behavior or treat mental illness. In his 1995 book "A History of Medicine – Volume I: Primitive and Ancient Medicine," historian Plinio Prioreschi proposed that cranial surgery was often performed on key members of society or hunters, perhaps to revive them during a severe illness or after an injury.

The ancient Roman physicians Hippocrates and later Galen documented trepanation as a way to remove damaged tissue and elevate depressed skull fractures. They wisely warned against penetrating the dura mater—the protective membrane surrounding the brain—or the brain itself, as this often led to severe complications like infections, seizures, and even death.

"The Romans used instruments known as terebrae, which were similar to the tumis used by the Incas," says Faria. "The terebra eventually evolved into the modern burr hole drill. During the Middle Ages and the Renaissance, trepanation was performed not just for skull fractures but also to treat madness and epilepsy. One famous painting by Hieronymus Bosch depicts the extraction of the stone of madness."

In European medical tradition, trepanation was primarily used to treat epilepsy and mental disorders like mania and melancholy. A 13th-century surgical manual recommended drilling into the skulls of epileptics so that "the humors and air may go out and evaporate." By the 17th century, however, the practice of trepanation was starting to be seen as a last-resort measure within the medical community.

Contemporary Trepanation

While the history of trepanation, or trepanning, stretches far back, it's worth noting that the procedure is still performed today for various medical conditions. Though modern doctors no longer call it "trepanation" — that's a term mainly used by medical historians — the practice lives on. Today, "burr holes" are drilled in the skull to biopsy brain tissue, diagnose brain lesions, treat skull fractures, remove tumors, or clip cerebral aneurysms. When the hole is made larger, it's referred to as a "craniotomy."

Faria notes that, despite the global reach of Western influence, basic forms of trepanation are still practiced by shamans in some African regions, as evidenced by journalists who have witnessed and documented these procedures in remote villages. These operations are said to be performed to treat skull fractures.