Evidence of trepanation has been found in prehistoric human remains. 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.
Trepanations appear to have been most common in areas where weapons that could produce skull fractures were used. Theories for the practice of trepanation in ancient times include spiritual purposes and treatment for epilepsy, headache and mental disorders.
Trepanation is perhaps the oldest surgical procedure for which there is archaeological evidence and in some areas may have been quite widespread. At one burial site in France dated to 6500 BC, 40 out of 120 skulls had trepanation holes. Evidence suggests that many of those subjected to the surgery survived.
Hippocrates gave detailed instructions on the procedure and during the Middle Ages and the Renaissance, trepanation was practiced as a cure for various ailments, including seizures and skull fractures. Surprisingly, evidence suggests that the survival rate was high and the infection rate was low.
In ancient times, trepanation instruments were were commonly made out of flint or harder material such as stone knives and later with metal such as bronze and copper. The procedure was done by shamans or witch doctors.The Greeks and Romans designed medical instruments that included the terebra serrata made to perforate the cranium by manually rolling the instrument between the surgeon's hand. By the Renaissance period, when trepanation was routinely performed, a range of instruments was developed to accommodate the demand.
The procedure includes exposure of the dura mater without damaging the underlying blood vessels, meninges, and brain. Over time, the skin will reform over the puncture site, but the hole in the skull will remain. The location of the trepanation on the skull varies by geographical region and period, common locations are the frontal and the occipital bones.
The procedure could result in severe complications which include increased damage to the brain, infection, blood loss, hemorrhage, and potentially death due to the trauma as the skull's protective covering is compromised The operation had very minimal space for error and a high incidence of mortality, if the dura matter was penetrated. Additionally, there was a high risk of infection and possibly significant and permanent brain damage. Even so, some individuals survived multiple skull surgeries.
The practice of trepanning continues today due to belief in various pseudoscientific medical benefits. Some proponents claim the procedure results in increased blood flow. In 1965, Dutch librarian Bart Huges drilled a hole in his own head with a dentist drill as a publicity stunt. Huges claimed it increased brain blood volume and enhanced cerebral metabolism in a manner similar to taking ginkgo biloba. Huges and his girlfriend also made several comic books in the 1970s, which promoted trepanation.
Among other arguments, Huges contends that children have a higher state of consciousness and since children's skulls are not fully closed, one can return to an earlier, childlike state of consciousness by self-trepanation. Further, by allowing the brain to freely pulsate Huges argues that a number of benefits will accrue. There is a British group that advocates self-trepanation to allow the brain access to more space and oxygen. In 2000, two men from Cedar City, Utah, were prosecuted for practicing medicine without a license after they performed a trepanation on an English woman to treat her chronic fatigue syndrome and depression.