Evidence of trepanation has been found in prehistoric human remains from Neolithic times onward. Cave paintings indicate that people believed the practice would cure epileptic seizures, migraines, and mental disorders. The bone that was trepanned was kept by the prehistoric people and may have been worn as a charm to keep evil spirits away. Evidence also suggests that trepanation was primitive emergency surgery after head wounds to remove shattered bits of bone from a fractured skull and clean out the blood that often pools under the skull after a blow to the head. Such injuries were typical for primitive weaponry such as slings and war clubs.
There is some contemporary use of the term. In modern eye surgery a trephine instrument is used in corneal transplant surgery. The procedure of drilling a hole through a fingernail or toenail is also known as trephination. It is performed by a physician or surgeon to relieve the pain associated with a subungual hematoma (blood under the nail); a small amount of blood is expressed through the hole and the pain associated with the pressure is partially alleviated.
Trepanation is perhaps the oldest surgical procedure for which there is forensic evidence, and in some areas may have been quite widespread. Out of 120 prehistoric skulls found at one burial site in France dated to 6500 BC, 40 had trepanation holes. Many prehistoric and premodern patients had signs of their skull structure healing; suggesting that many of those subjected to the surgery survived.
Trepanation was also practiced in the classical and Renaissance periods. Hippocrates gave specific directions on the procedure from its evolution through the Greek age, and Galen also elaborates on the procedure. During the Middle Ages and the Renaissance, trepanation was practiced as a cure for various ailments, including seizures and skull fractures. Out of eight skulls with trepanations from the 6th to 8th centuries found in southwestern Germany, seven skulls show clear evidence of healing and survival after trepanation suggesting that the survival rate of the operations was high and the infection rate was low.
Although widely considered today to be pseudoscience, the practice of trepanation for other purported medical benefits continues. Moreover, some proponents point to recent research on the increase in cranial compliance following on trepanation, with resulting increase in blood flow, as providing some justification for the practice. Individuals may practice non-emergency trepanation for psychic purposes. A prominent proponent of the modern view is Peter Halvorson, who drilled a hole in the front of his own skull to increase "brain blood volume". Other modern practitioners of trepanation claim that it holds other medical benefits, such as a treatment for depression or other psychological ailments. In 2000, two men from Cedar City, Utah were prosecuted for practicing medicine without a license after they performed a trepanation on an English woman to treat her chronic fatigue syndrome and depression.