Paul Broca, famed neuroscientist, asserted that the surgery was practiced on live humans with a 67% survival rate, despite its apparent riskiness.
The tradition of trephining as a treatment for epilepsy begins as early as Aretaeus the Cappadocian, one of the most famous Greek clinicians, and lasted into the eighteenth century. The thirteenth-century surgical text Quattuor magistri recommended opening the skulls of epileptics ‘‘that the humors and air may go out and evaporate.’’ However, by the seventeenth century trephination for epilepsy was beginning to be viewed as an extreme measure.
The earliest detailed account of trephining is in the Hippocratic corpus, the ﬁrst large body of Western scientiﬁc or medical writing that has survived. The most extensive discussion of head injuries and the use of trephining in their treatment is in the Hippocratic work 'On Wounds in the Head'.
Researchers from the Universities of Oviedo and Leon were surprised when they found two trepanned skulls in the medieval San Miguel hermitage cemetery. They were even more surprised when they found that one of the skulls belonged to a woman. Even when trepanation was widely performed, most of the patients were men.
There were at least four different methods of trepanning. The crudest was to simply scrape a hole in the skull-cap, with patience and a piece of flint or a polished mussel-shell Most elegant, though, was the procedure which gave this operation its name. With a drill-bore, called trypanon in Greek, a wreath of tiny holes was made. These could be united easily with a chisel or knife. Such an operation took little time even with primitive tools. An adept French surgeon, J. Lucas-Championnière (1843-1913), experimenting with instruments of flint, needed only 35 minutes to complete the operation.
Holes in bone are healed by new formation of bone tissue, and the sharp edges of bored or hacked holes become rounded off by so-called callus tissue. This proof of healing is more the rule than the exception. In one study of skull material from the Yantyo tribe in Peru, a researcher found callus tissue in 250 out of 400 crania.
Heather Perry, from Gloucester, travelled to Utah last February to undergo the procedure, aided by Peter Halvorson, 54, and William Lyons, 56. Ms Perry, a chronic fatigue sufferer , said she had experienced a "definite improvement" in her health since the procedure.
Nowadays, trepanation is a routine surgical technique. In particular, it is often performed to treat subdural hematoma -- life-threatening bleeding from membranes covering the brain -- which can occur after a blow to the head.
Though anthropologists believe it was traditionally used to expel evil spirits, even from ancient times trepanation has been performed to treat a variety of more tangible conditions, from headaches to insanity.
The oldest trepanned skull, found at a neolithic burial site of Ensisheim in France, is more than 7,000 years old, and trepanation was practised by the Ancient Egyptians, Chinese, Indians, Romans, Greeks and the early Mesoamerican civilizations. The procedure is still performed today, for both medical and non-medical reasons.