Prehistoric trepanation

A grave at Ensisheim in Alsace held the skeleton of a man who died at about 50, buried with an arrowhead and an adze of a type dated to 5100 to 4900 BC; a radiocarbon date from the bone agreed. His skull had two large openings. The one toward the front, about 2.6 by 2.4 inches, had healed completely. The other, about 3.7 by 3.6 inches and apparently made by intersecting cuts, had partly healed. The healing showed that he survived both operations. The skull showed no sign of injury or disease that would explain them. Kurt Alt of Freiburg University and colleagues reported it in Nature in 1997 as the earliest unequivocal evidence of trepanation.

Trepanation means scraping, cutting or drilling an opening into the skull. In a 2010 review John Verano and Stanley Finger wrote that it was practised in Europe more than 5,000 years ago and in the Americas from as early as the 5th century BC. Verano has also warned that many published cases rest on a single skull with a healed hole, and that birth defects, injury, infection, tumours and damage in the ground can all leave similar openings. Unhealed cases are easier to judge because the tool marks remain.

More trepanned skulls have been found in Peru than anywhere else. Studying more than 800 of them over nearly three decades, Verano, David Kushner and Anne Titelbaum estimated long-term survival at about 40% in the earliest period, 400 to 200 BC, rising to 91% in samples from AD 1000 to 1400 and averaging 75% to 83% under the Inca. The successful operations were probably shallow and did not pierce the dura mater. In the Cuzco region, Valerie Andrushko and Verano found 109 openings in 66 people from 11 burial sites, made mostly by circular cutting or scraping. Survival there was 83%, with little sign of infection, and many operations seem to have followed head injuries.

For comparison, the same 2018 study put the mortality of cranial surgery in the American Civil War at 46% to 56%. Physicians only began to accept in the mid-19th century that such holes in ancient skulls were surgical and had been made in living people. Paul Broca and Victor Horsley were among the first to write about them, and they disagreed about why the operations were done.