Really. This surgery, called trephining or trepanning, removes a piece the skull from a living patient to expose a layer of the brain, the dura mater, which translates to “ tough mother” (Really!). As the name suggests this layer is a tough fibrous membrane which forms the outer envelope of the brain.
The operation was surprisingly common, showing up on many Neolithic skull and was practiced in many areas of the world, with the highest concentration of activity in Peru and Bolivia. Evidence for it also is found in Europe, Asia, New Zealand, some Pacific Islands and North America.
The operation was most often performed on adult males, although it was also performed on women and children. Overall, patients that underwent the operation had an impressive recovery rate. As many as two thirds of the skulls examined reveal various degrees of healing--which is the evidence for survival. Considering the danger of severe bleeding, shock, brain edema, and infection, such postoperative results suggest considerable skill and experience.
The motives for Neolithic trephining have been the subject of speculation since the first specimens were discovered in the nineteenth century. Obviously, the people involved are not around to tell us why they did it and writing did not yet exist. One guess is that it was done to create an entrance or exit for spirits. It might also have been done for therapeutic reasons, such as for headaches, fractures, infections, insanity, or for convulsions.
The operation is still done to treat epidural and subdural hematoma. But today, skilled surgeons do it. And they use modern stainless-steel drills, not rocks!