Trepanning
The idea of trepanning is relatively simple. Evil spirits trapped within the human mind need to be released, and in order to do so an opening must be made in the body to allow them to get out. Since evil spirits seemed to be occupying the mind of the patient, located of course in the head, an opening in the head would offer them the egress they sought through inducing odd or unacceptable behavior in the patient. So the doctor would drill a hole in the head to let them out.
There were other situations in which trepanning was considered to be the optimal treatment. Head wounds often lead to trepanning (also called trepanation) to remove shattered bone fragments or foreign matter left in the skull. Trepanation seems to have sprung up among numerous ancient cultures and locations, including among the ancient peoples of Europe, North America, and Africa.
Surprisingly, given the incidence of infection and the lack of antiseptic procedures and medicines, evidence from a large number of trepanned skulls found by archaeologists indicates that the survival rate for those undergoing the operation was high. By the eighteenth century trepanning was considered to be called for to relieve seizures caused by head injury, or from epilepsy and other illnesses.
Trepanning was a common practice among the natives of Polynesia, as French and English sailors discovered during their voyages of exploration in the South Pacific. Archaeologists have discovered trepanned skulls in the ruins of the Mayan and Aztec civilizations. It was performed by the diverse civilizations of Africa, in Asia, and in Ancient Greece, which culture gave it its name. Trepanning, which is also known as trephination, is derived from the Greek word trypanon, meaning to auger.
Today, the operation is sometimes performed to relieve pressure on the brain resulting from hematomas, but trepanning is obviously no longer indicated for the release of evil spirits. Surgeons no longer refer to the procedure as trepanning, preferring the term craniotomy, and the removed portion of the skull is usually replaced. Nor do trepanning instruments resemble the modern tools available to today’s surgeons.