Trepanning

Trepanning was sometimes performed on people who were behaving in a manner that was considered abnormal. In some ancient societies it was believed this released the evil spirits that were to blame. Evidence of trepanation has been found in prehistoric human remains from Neolithic times onward. During that time, trephined skulls were commonly found in central Europe. After the Neolithic era, trephined skulls became less common due to the increased use of cremation. The bone that was trepanned was kept by the prehistoric people and may have been worn as a charm to keep evil spirits away. Evidence also suggests that trepanation was primitive emergency surgery after head wounds to remove shattered bits of bone from a fractured skull and clean out the blood that often pools under the skull after a blow to the head. Trepanation was also used for the purposes of removing splinters from head wounds and cranial decompression. Hunting accidents, falls, wild animals, and weapons such as clubs or spears could have caused such injuries. War injuries such as a bullet wound can mimic a trephined skull. Trepanations appear to have been most common in areas where weapons that could produce skull fractures were used. The primary theories for the practice of trepanation in ancient times include spiritual purposes and treatment for epilepsy, head wounds, mental disorders, and headaches, although the latter may be just an unfounded myth. Studies show that trepanation was used on individuals that were diagnosed with epilepsy, scurvy, frontal sinustis, intracranial disorders, diseases, hydrocephaly, and osteitis.

In modern eye surgery, a trephine instrument is used in corneal transplant surgery. The procedure of drilling a hole through a fingernail or toenail is also known as trephination. It is performed by a physician or surgeon to relieve the pain associated with a subungual hematoma (blood under the nail); a small amount of blood is expressed through the hole and the pain associated with the pressure is partially alleviated. Similarly, in abdominal surgery, a trephine incision is when a small disc of abdominal skin is excised to accommodate a stoma. Although the abdominal wall does not contain bone, the use of the word trephine in this context may relate to the round excised area of skin being similar in shape to a burr hole.

History

Prehistoric evidence

Trepanation dates back to 7,000–10,000 years ago, is perhaps the oldest surgical procedure for which there is archaeological evidence, and in some areas may have been quite widespread. Trepanation is a worldwide practice that was extremely common during the Neolithic era. The main pieces of archaeological evidence are in the forms of human remains. At one burial site in France dated to 6500 BCE, 40 out of 120 prehistoric skulls found had trepanation holes. At the time only around 40% of people survived the procedure. A skull of a child in an Harappan burial at Lothal dated to 2200 BCE shows signs of trepanation.

More than 1,500 trephined skulls from the Neolithic period (representing 5–10% of all cranial remains from that era) have been uncovered throughout the world – from Europe, Siberia, China and the Americas. Most of the trephined crania belong to adult males, but women and children are also represented.

There also exists evidence of trepanation being performed on a cow in France around 3400–3000 BCE. If performed while alive, the cow did not survive the procedure. It is unclear if this was performed as a veterinary procedure, medical experimentation or for other unknown reasons. However, it could be the earliest archaeological example of veterinary surgery or animal medical experimentation.

Pre-Columbian Mesoamerica

In the more recent times of postclassical pre-Columbian Mesoamerica, evidence for the practice of trepanation and an assortment of other cranial deformation techniques comes from a variety of sources, including physical cranial remains of burials, allusions in iconographic artworks and reports from the post-colonial period.

Among New World societies, trepanning is most commonly found in the Andean civilizations, such as pre-Incan cultures. For example, the Paracas culture Ica, situated in what is now known as Ica, located south of Lima. The oldest skull can be found in Paracas culture (700BC - AD300). Roman cultures left behind evidence of the practice by leaving lectures and writings written by scholars. Trepanation has also been found in the Muisca Confederation (in modern-day Colombia) and the Inca Empire. The Inca Empire used trepanation as a treatment for epilepsy and medicine. The rate of skulls being found in Perú were significantly high. Between 11 and 40% of skulls were found throughout different parts of the area. Instruments and techniques used in Perú seemed advanced due to the number of trephined skulls that missed the midline of the skull. This suggests that these cultures tried to decrease the risks and damages of this procedure. Avoiding the midline of the skull reduced damage to the cerebral sagittal sinus. This reflects the improvement in the survival rate increasing over time to 80%. In both, even cranioplasty existed. The prevalence of trepanation among Mesoamerican civilizations is much lower, at least judging from the comparatively few trepanned crania that have been uncovered.

The archaeological record in Mesoamerica is further complicated by the practice of skull mutilation and modification carried out after the death of the subject, to fashion "trophy skulls" and the like of captives and enemies. This was a widespread tradition, illustrated in pre-Columbian art that occasionally depicts rulers adorned with or carrying the modified skulls of their defeated enemies, or of the ritualistic display of sacrificial victims. Several Mesoamerican cultures used a skull-rack (known by its Nahuatl term, tzompantli), on which skulls were impaled in rows or columns of wooden stakes. Even so, some evidence of genuine trepanation in Mesoamerica (i.e., where the subject was living) has survived.

The earliest archaeological survey published of trepanned crania was a late 19th-century study of several specimens recovered from the Tarahumara mountains by the Norwegian ethnographer Carl Lumholtz. Later studies documented cases identified from a range of sites in Oaxaca and central Mexico, such as Tilantongo, Oaxaca and the major Zapotec site of Monte Albán. Two specimens from the Tlatilco civilization's homelands (which flourished around 1400 BCE) indicate the practice has a lengthy tradition.

Specimens identified from the Maya civilization region of southern Mexico, Guatemala and the Yucatán Peninsula show no evidence of the drilling or cutting techniques found in central and highland Mexico. Instead, the pre-Columbian Maya apparently used an abrasive technique that ground away at the back of the skull, thinning the bone and sometimes perforating it, similar to the examples from Cholula. Many skulls from the Maya region date from the Postclassic period (c. 950–1400 CE), and include specimens found at Palenque in Chiapas, and recovered from the Sacred Cenote at the prominent Postclassic site of Chichen Itza in northern Yucatán.

Ancient China

Before 2007, archaeological evidence of trepanation in ancient China was nonexistent. Since Chinese culture mainly focuses only on traditional Chinese medicine that usually entails non-surgical treatments such as acupuncture, balancing Qigong, cupping, herbal remedies, etc. The resulting misconception was that trepanation was not practiced in ancient China. Trepanned skulls have been found since the 1940s throughout China. Some of these skulls have dated back to the 3rd and 1st century BCE. However, in 2007, Han and Chen from the Institute of Archeology, Chinese Academy of Social Sciences looked at six trepanned skulls spanning between the Neolithic period through the Bronze and Iron Ages (c. 5000–2000 years ago) found in five different locations. Along with the discovery of these trepanned skulls, another collection of 13 trepanned skulls was discovered and dated to 3,000 years ago. In 2015, an intact 3,600-year-old mummy with a trepanned skull was discovered. Meanwhile, the oldest trepanned skull (M382) analysed by Han and Chen was radiocarbon dated to around 5,000 years ago and discovered at the Fuija site in Guangrao, Shandong. The skull, which belonged to an adult male, exhibited a right parietal calvarial defect (31 x 25 mm) with evidence of scraping by a trephine-like tool. Additionally, bone regeneration and smooth edges suggest that the subject recovered from the surgery and lived a relatively long time afterward.

The 3,600-year-old perforated skull of a mummified female dating to 1615 BCE was found in the Xiaohe tomb in China's Xinjiang Uygur Autonomous Region. The only known female with a trepanned skull, it showed signs of bone spurs growth and retraction of the edges, suggesting that she also survived the surgery. Found in a massive burial site, this mummy was one of the hundreds found in the "Little River" Tomb complex.

The Bronze Age was found to be the period with the largest number of trepanned skulls in ancient China.

Medieval East Africa

Trephining has a long history in East Africa. Bones of depressed fractures were elevated by surgeons of Bunyoro-Kitara. The hair may or may not have been shaved depending upon the site of the operation.

Trepanning at the Kisii people in Kenya was filmed in 1958.

Pre-modern Europe

Trepanation was known to prehistoric Europeans, with some populations having impressive success rates of 78% in the Iron Age. Central Europe during the Neolithic era had an important understanding of the risks of trepanation. They used aids like rudimental anesthetic, antiseptic, and technological aids.

Trepanation was also practised in the classical and Renaissance periods. Hippocrates gave specific directions on the procedure from its evolution through the Greek age, and Galen also elaborates on the procedure. During the Middle Ages and the Renaissance, trepanation was practiced as a cure for various ailments, including seizures and skull fractures. Out of eight skulls with trepanations from the 6th to 8th centuries found in southwestern Germany, seven skulls show clear evidence of healing and survival after trepanation, suggesting that the survival rate of the operations was high and the infection rate was low.

In the graveyards of pre-Christian (Pagan) Magyars, archeologists found a surprisingly high frequency (12.5%) of skulls with trepanation, although more than 90% only partial (these served probably ritual purposes). The trepanation was performed on adults only, with similar frequencies for males and females, but increasing frequency with age and wealth. Additional research has suggested that the male to female proportion of these individuals was 2:1. Children accounted for only 7% of trephined skulls. This custom suddenly disappeared with the Magyars' conversion to Christianity.

A small area near (modern) Rostov-on-Don, in southern Russia, may have been a centre for ritual trepanning, around 6000 years ago, according to archeologists who discovered remains of eight recipients of the practice, within a small area, all with the incision in the unusual obelion position, high on the back of the head.

During the 16th and 17th centuries, around 80% of people survived the procedure of trepanation.

Modern medical practices

The prefrontal leucotomy, a precursor to lobotomy, was performed by cutting a trephine hole into the skull, inserting an instrument, and destroying parts of the brain. This was later made unnecessary by the development of the orbital transit lobotomy where a spike was inserted through the eye-sockets.

Trepanation is a treatment used for epidural and subdural hematomas, and surgical access for certain other neurosurgical procedures, such as intracranial pressure monitoring. Modern surgeons generally use the term craniotomy for this procedure. Unlike in folk practices, a craniotomy must be performed only after diagnostic imaging (like computed tomography and magnetic resonance imaging) has pinpointed the issue within the skull; preoperative imaging allows for accurate examination and evaluation. Unlike in trepanation, the removed piece of skull (called a bone flap) is typically replaced as soon as possible, where it can heal. Trepanation instruments, nowadays being replaced with cranial drills, are now available with diamond-coated rims, which are less traumatic than the classical trephines with sharp teeth. They are smooth to soft tissues and cut only bone. Additionally, the specially designed drills come with a safety feature that prevents the drill from penetrating into the brain tissue (through the dura mater). Along with antisepsis and prophylaxis of infection, modern neurosurgery is a common procedure for many reasons other than head trauma.

In documented cases of trepanning done in Africa and Oceania during the 20th century, patient survival rate was seen to be approximately 90%.

Myth of trepanation as a treatment for headaches

After the retrieval of some skulls from the Neolithic era that showed signs of trepanation, in the nineteenth century, the false belief that these holes were drilled for the treatment of headaches or other neurological disorders started spreading. During the 1870s, the French anthropologist and physician Paul Broca found several European and South American children's skulls dating to the Neolithic age that were perforated surgically. Since no signs of fractures that could justify this complex procedure to relieve trauma were found, a debate emerged around why these children were subjected to trepanation while they were still alive. Broca theorized that this operation had a ritual or religious purpose, probably to remove "confined demons" inside the head of the patient, or to create healing or fortune talismans with the removed skull fragments. Superstitions were created by ancient settlers who believed that drilling a hole in the skull would release demons. However, he also suggested that the operation may have been performed to treat some infantile conditions such as febrile seizures to explain why it was performed only on children. Broca also concluded that trephination was mostly performed on live patients.

Broca never mentioned headaches, though, and the association was established only several decades later by the world-famous Canadian physician William Osler in 1913. Osler misinterpreted Broca's words, and added other conditions such as "infantile convulsions, headache and various cerebral diseases believed to be caused by confined demons." Osler's theory was seen as particularly palatable by other armchair anthropologists, who were fascinated by the idea that folk traditions and/or myths could be linked with the treatment for common conditions such as migraine. Eventually, Broca's speculation came to be accepted as fact, and the myth was perpetuated by other historians and physicians. To this day, there's no credible evidence supporting this theory, especially since children are much less frequently affected by migraine and headache disorders than adults. Nevertheless, the myth persists.

Cultural perspectives on trepanation

The motivations behind trepanation varied significantly across cultures, often tied to beliefs about health, spirituality, and the treatment of ailments. Early instances of the practice may have been influenced by a combination of supernatural beliefs and early understandings of physical ailments, leading to its acceptance in various medical traditions. In many cultures, it was believed that drilling a hole in the skull will let out the evil spirits that caused pain and illness. It can be explained as most head injuries and diseases, such as migraines, felt like pounding, so cutting a hole in the head may help to relieve the pain and pressure. In Africa and Europe, not only was this procedure performed for spiritual reasons, but also the discs made of cranial bones were commonly used as a shield from demons and evils. In China, twelve shaman corpses in a tomb were found with trephined bodies because they also had duties of doctors. This shows the connection between cranial surgery and religion; there was a conception that an open hole in the head contributed to communication with gods and the souls of dead people. In tribal groups, trepanning was seen as a medicine to maintain youth and a cure for rheumatism. Priests were a common person to perform this procedure, leading to beliefs of metaphysical objectives like exorcism. Trepanation was also associated in Chinese medicine with the balance of vital energy, or qi. They understand trepanation as a way to balance the body and energy, spiritual and physical health. On the other hand, it was thought that cerebral disorders arise from the loss of the spiritual image in ancient Peru, an illness developed after being separated from the body. Trepanation would have been done in order to allow the spirit to reenter the body. In these cases, the patient may have suffered from paralysis, cerebral palsy, severe depression, or intellectual disability.