A set of trepanning instruments, containing Hey's saws (top), lenticulars, and three trephines (lower right). Trepanning (or trephining) instruments were used to surgically drill a hole in the skull of a living person, a procedure known as known as trepanation or trephination. Trepanation was used to treat a range of ailments from headaches to epilepsy, and the practice of creating holes in the living human skull dates back to ancient history. This set of instruments originates in England, around 1820.