There is an interesting history of skull surgery, known as trepanation, which comes from the Greek word trypanon, meaning auger or borer. Cranial trepanation has caught the interest of surgeons and archeologist since the 1860’s, when it was first realized that ancient humans had scraped or cut holes in the skulls of living persons in France and Peru.
Why would primitive cultures of France, nearly 4000 years ago, practice trepanation? The suggested reasons for this surgery are numerous but not substantiated. Researchers over the last century and a half have speculated that cranial surgery was done in cases of trauma from battle or accident, cranial infections, headaches, mental disease, and religious rituals. Rituals involving the opening of the skull were believed to facilitate the exit of evil spirits that caused epilepsy. This seems plausible because in almost every age and culture epileptic seizures were believed to be the work of evil spirits.
Examination of Peruvian skulls, by today’s physicians, reveals that these cranial surgeries rarely became infected, and most survived. Even more impressive are the skulls exhibiting successful cranio-plasties (plates inserted into the trephination holes) made of silver and gold, which were placed with such skill that the bone healed around them. In contrast, during the 18th century, trephination of the cranium in Europe reached a nearly 100% fatality rate. (Via)