Evil spirits in your head
While the ancient technique of trepanation may seem crude, based on mankind’s historically limited understanding of neurology, health, and not to mention, sterile technique, this type of brain surgery happens to be one of the oldest surgical procedures invented by mankind, and is the oldest neurosurgical procedure. It is thought to be even older than the use of metal instruments or even the written language. And it may surprise you, but this procedure was not entirely unusual. In this episode of BrainWaves, we’ll shed some light on the history of this ancient technique, and maybe you won’t think it was so crazy after all.
At the time of its conception, somewhere about 10,000 years ago in what may be present day Peru, somebody had a
fair idea as to what they were doing. Sure, you might be skeptical. There is no way humans have been drilling holes into other, live humans for thousands of years! You might be thinking that the holes found in skulls of dead people were the result of trauma—like a spear or arrowhead through the skull, or if placed by surgical instrumentation, then they were performed after death. But as a matter of fact, many patients who underwent trepanation had tissue evidence that the skull had begun to heal, indicating this procedure was done on living people, and that people even survived after the procedure was performed.
While the term trepanation has its origins from the Greek word, trepanon (ανατρησιζ), for “borer” or “auger,” the technique was originally practiced in many Mesolithic era societies spanning nearly all of the major continents today: Africa, Asia, Europe, South America, and Mesoamerica. And even more interesting was that this procedure was independently discovered by each of these peoples. At the time of its conception, based on our limited ability to know what people were thinking thousands of years ago, trepanation was thought to expel from the mind the evil spirits which were responsible for convulsions, headaches, and other inexplicable symptoms or behaviors. At least, that is what Paul Broca gathered from his research on the matter. This opinion was shared by William Osler, our “father of modern medicine.”
Victor Horsley, a contemporary of Broca and someone equally knowledgeable on the subject, objected to these limited perspectives. He posited that trepanation may have originally been used to treat pain or epilepsy in the setting of skull fractures in many South American and Eastern societies. Despite these contesting opinions, each unique culture likely had their own independent rationale for making holes out of skulls. All things considered, the Egyptians ought to be credited with the first and most physiologically accurate understanding of this early surgical procedure.
The Edwin Smith Papyrus, Earth’s oldest known truly medical document (other documents may outdate it but lack scientific rhetoric) which dates back to the 17th century BCE, contained some of the earliest descriptions of neuroanatomy. The Edwin Smith Papyrus described parts of the skull, the meninges, and identified the cerebrospinal fluid as something unique from other bodily solutions. It strongly disputed other famous texts of about that era, notably the Ebers Papyrus, which emphasized more mysticism than medicine. In addition to being a highly accurate anatomical reference, the Smith Papyrus also described some of the earliest clinical practices. In particular, it offered recommendations for the management of brain and spinal trauma. However, while ancient Egyptian corpses around the time of this text have been identified as having surgically placed bore holes, the Edwin Smith papyrus makes no mention of the use of trepanation. So Broca may actually have been correct in supposing that trepanation had no truly biologic or physiologic indications, at least among early Egyptians. Maybe trepanation had less of a scientific basis and more of a mystical one for these peoples.
The next major shift in clinical thought came about in the fifth century BCE. Around this time, Hippocrates of Cos, the “father of medicine,” would publish his famous neurosurgical text, “On injuries of the head.” This was only one of his many medical texts, which would become the world’s foremost resources that transformed medical practice from one of magic and mysticism to one of observation and interpretation. While trepanation had previously been used to treat certain headaches, Hippocrates was one of the first to describe various headache syndromes as pathologic states which related to an underlying biologic condition. In “On injuries of the head”, Hippocrates described various causes and complications of traumatic head injury, bony contusions, skull fractures, and a variety of surgical interventions for these patients who suffered from diseases affecting the brain. Hippocrates even distinguished which cases were operable, and which injuries would inevitably end in death.
Regardless of the indications for the procedure, the technique of trepanation has evolved over the millennia. In ancient Greece at the time of Hippocrates, there were 3 major styles (image to right). The oldest of the styles involved scraping of bone. Often used for necrotic tissue, a semi-sharpened instrument was used on patients to grind down a small region of the skull until the underlying meninges were exposed. A second style, one more modern, involved a serrated trephine that took the form of a ring-like drill attached to the end of a rod. With the serrated ring affixed to the skull, the rod would be rotated and eventually a ring of bone would be wholly excised. Finally, a third approached used what looks like a large, fancy drill bit, called a terebra serrata. This device would grind out a hole in the skull, leaving shards of bone and soft tissue residue around the surgical site.
Interestingly, Hippocrates only acknowledged the use of trepanation in head injury; and furthermore, he never clearly documented why trepanation would be of any clinical benefit. Regarding the use of trepanation to relieve intracranial pressure caused by fluid buildup, it would be another 600 years before Galen offered his own theorizes regarding the physiology of trepanation, and another 2,000 years before the Monro-Kellie doctrine was officially described. It may sound like I’m overly critical of Hippocrates for getting a lot of these principles wrong, but truth-be-told, he rationalized many surgical procedures, including trepanation. Through his collected and widely disseminated works, he encouraged physicians of antiquity to practice medicine using their minds rather than their magic. His methods were unprecedented, and they undoubtedly shaped the way care was delivered to many people for the next one thousand years, until Galen of Pergamon picked up the reins.
Arguably the most dedicated student of Hippocratic teaching, Galen built upon his earlier master’s work. He added to Hippocratic works invaluable neuroanatomic observations, recognizing for example the symptoms of hydrocephalus and the role of the ventricular system, the localization of arm or leg weakness to injury of the spinal column, and the functions of certain cranial nerves. He also refined the technique of trepanation himself, in a time where this technique was more widely acceptable than in fifth century BCE Greece at the time of Hippocrates. As far as the indications for this procedure, which were vague in the writings of Hippocrates, Galen acknowledged many of these purposes. It was Galen who first documented the role of trepanation in draining “phlegmatous” lesions of the head and to relief pressure caused by intracranial hematomas. The indications for trepanation slowly shifted away from the mysticism of evil spirits and toward the rational practices that would transform into Western medicine.
In the years following Galen’s seminal contributions to medicine and surgery, about the time of the Middle Ages and early Renaissance, trepanation fell out of favor in civilized Europe. Surgery in general was considered a desecration to the human body, and it opposed the natural order that God had instilled in our physical forms. In the year 1163 CE, the Catholic Church proclaimed, “Ecclesia abhorret a sanguine”: The Church detests blood. Surgery became a crime for much of the Middle Ages in Europe, and furthermore, anatomic dissection of the deceased for the purpose of education was also condemned. This was until physicians like Guy de Chauliac and later Andreas Vesalius published extensively on their anatomic observations of human corpses. These findings progressively grew in importance during the war-stricken Renaissance where injuries to the body and especially the head became increasingly common.
By the 16th century, trepanation made its grand resurgence in European medicine. Worth noting here is that, although trepanation became more socially acceptable by many European nations, it failed to make gains as a safe and effective surgical procedure anywhere in the world until the mid-nineteenth century when American physicians, Dr. Collins Warren and William Morton began to popularize the concept of general anesthesia using ether vapor in 1848. And while the antiseptic technique was originally described by Joseph Lister in 1867, it would be another several decades before it was universally implemented in western medical practice.
Fast forward to the present day, where trepanation is now referred to as craniotomy. While the procedure carried significant risk 5,000 years ago, now, it is so simple today that a 1st year neurosurgery resident can quickly learn to place an external ventricular drain at the bedside without any supervision. But we are still not getting it perfectly right. In the early 20th century, Harvey Cushing, a physician heralded as the father of neurosurgery—and someone worthy of that title—would also perform craniotomies for intractable headaches. Obviously, the scientific rationale used by Cushing here, to treat migraines by removing skulls, was not among his best work. And still, craniotomy was performed for the treatment of schizophrenia, depression, and other mood disorders through the mid-twentieth century, Americans called it “psychosurgery” at the time. Craniotomies were also performed to alleviate cluster headaches in some settings up until the 1970s, despite the lack of evidence that they even worked for that indication!
As we’ve expanded our scientific knowledge, improved upon the sterile technique, and refined the instruments involved in neurosurgery, surgeons have begun to narrow down the main indications for craniotomy which actually benefit patients. We live in an era of evidence-based medicine. Observations are made and interventions are systematically and scientifically tested to determine safety and efficacy. It’s easy to look back thousands of years ago and say, “that was really really dumb. What were they thinking?” But I know that physicians in the future will be saying the same thing about those of us in practice today. “That was really really dumb. What were they thinking?” I can only hope we’re heading in the right direction.
BrainWaves’ podcasts and online content are intended for medical educational purposes only. Please do NOT drill into anyone’s head without their full and informed consent.
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