Also known as trepanning, trephination was an ancient practice dating way back as early as the Mesolithic era. It was a procedure whereby a hole was bored into the skull of patients suffering from schizophrenia, epileptic seizures or migraines. It was believed that evil spirits thought to be responsible for abnormal behavior and mental disturbances could be released through the cranial opening. The surgery was achieved using augurs and saws and was likely painful due to the absence of modern anesthesia. The removed portion of bone was replaced shortly after but often healed with some distortion in the skull’s shape and contour.