"From the Middle Ages well into the 18th century in Europe, trepanning was common as a medical procedure very much like bloodletting, i.e.; it had no medical usefulness per se. Repeated trepanning was common; for instance it is related that Prince Philip of Orange was trepanned 17 times by his physician. De La Touche, a French physician trepanned 52 times one of his patient, within a two-month period! Many physicians, from the Roman times on, also believed that the bone slabs (called rondelles) taken from trepanned skulls had therapeutic value when pulverized and mixed with other beverages given to the patients for several diseases. "
