Trepanning – also referred to as trephination, trepanation, trephining or making a burr hole – has been practiced for around 5,000 years, making it one of the oldest medical procedures known to the human race. In short, it involves drilling or carving a hole into a person’s skull.
Traditionally used to treat various ailments ranging from head trauma to epilepsy, there is evidence of trepanning in 5-10 percent of all Neolithic (8,000-3,000 BC) skulls from Europe, Scandinavia, Russia, North and South America and China, as well as many other areas besides.
Perhaps the most surprising fact about the procedure is that people often survived it: many ancient skulls display evidence of having undergone trepanning multiple times.
So what is trepanning? Why was it done, and is it still performed today?
It was used to treat both physical and mental afflictions
Evidence suggests that trepanning was performed to treat multiple afflictions. It appears that it was most commonly conducted on those with head injuries or as an emergency surgery after head wounds. This allowed people to remove shattered bits of bone and to clean out the blood that can pool under the skull after a blow to the head.
Everything from hunting accidents, wild animals, falls or weapons could have caused head injuries of the like; however, trepanning has been most commonly observed in cultures where weapons were widely used.
It is also clear that trepanning was sometimes used to treat mental health conditions or disorders such as epilepsy, a practice that continued into the 18th century. For instance, celebrated ancient Greek physician Aretaeus the Cappadocian (2nd century AD) wrote of and recommended the practice for epilepsy, while in the 13th century a book about surgery recommended trepanning the skulls of epileptics so that “the humors and air may go out and evaporate”.
It is also likely that trepanning was used in some rituals to pull spirits from the body, and there is evidence across many cultures that parts of removed skull were later worn as amulets or tokens.
It could be performed in various ways
Broadly, there are 5 methods used to perform trepanning throughout history. The first removed a part of the skull by creating rectangular intersecting cuts by using obsidian, flint or hard stone knives, and later metal ones. This method has most commonly been observed in skulls from Peru.
Most often observed in skulls from France was the practice of opening the skull by scraping away at it with a piece of flint. Though the method is slow, it was particularly common and persisted into the Renaissance. Another method was cutting a circular groove into the skull and then lifting away the small disc of bone; this technique was common and was widely used in Kenya.
It was also commonplace to drill a circle of closely-spaced holes, then cut or chisel the bone between the holes. A circular trephine or crown saw was sometimes used, and featured a retractable central pin and transverse handle. This piece of equipment has remained relatively unchanged throughout history, and is sometimes still used today for similar operations.
People often survived
Though trepanning was a skilled procedure often carried out on people with dangerous head wounds, evidence of ‘healed’ skull holes shows that people often survived trepanning in an estimated 50-90 percent of cases.
However, this has not always been widely accepted: in the 18th century, primarily European and North American scientific communities were confounded to discover that many ancient trepanned skulls showed evidence of survival. Since the survival rate for trepanning in their own hospitals barely reached 10%, and the healed trepanned skulls came from cultures perceived to be ‘less advanced’, scientists couldn’t fathom how such societies had historically conducted successful trepanning operations.
But 18th-century Western hospitals somewhat misunderstood the dangers of infection: diseases in Western hospitals were rampant and often resulted in trepanned patients dying post-surgery as a result, rather than during the operation itself.
Trepanning still exists today
Trepanning is still sometimes performed, though commonly under a different name and by using more sterile and safe instruments. For instance, the prefrontal leucotomy, a precursor to lobotomy, involved cutting a hole into the skull, inserting an instrument and destroying parts of the brain.
Modern surgeons also perform craniotomies for epidural and subdural hematomas and to gain surgical access for other neurosurgical procedures. Unlike traditional trepanning, the removed piece of skull is normally replaced as quickly as possible, and instruments such as cranial drills are less traumatic to the skull and soft tissue.
Today, there are instances of people intentionally practicing trepanning on themselves. For instance, the International Trepanation Advocacy Group advocates for the procedure on the basis that it provides enlightenment and enhanced consciousness. In the 1970s, a man called Peter Halvorson drilled into his own skull to try and cure his depression.