So far, the oldest testimony of such a surgical intervention dates back 7,000 years, updated in 2010 on a Neolithic site in France (Seine-et-Marne): an amputation of the arm of an elderly man, obviously successful because imaging of the ancient bones revealed signs of scarring.

Scientists generally agree to link the appearance of the first medical practices to the Neolithic revolution of around 10,000 years ago, when agriculture and sedentarization brought to light previously unknown health issues.

But the excavation of human remains at least 31,000 years old, in the Indonesian part of Borneo, upsets this vision by revealing that hunter-gatherers practiced surgery thousands of years earlier than estimated.

The discovery "rewrites our understanding of this medical know-how," said paleontologist Tim Maloney, from Griffith University in Australia, who led the study, which appeared in Nature on Wednesday.

The bones had been unearthed in 2020 in the imposing limestone cave of Liang Tebo, known for its cave paintings.

Among the countless bats, terns, swifts and even a few scorpions inhabiting the place, the paleontologists delicately removed the sedimentary layers and found the burial of a remarkably preserved skeleton.

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He was only missing his left ankle and foot.

The end of the remaining leg bone showed a "sharp and oblique cut, which you can see by looking through the bone", described Tim Maloney during a press conference.

An appearance that would have been less regular if the amputation had been caused by a fall or an animal attack.

So many clues not of an accidental amputation, but of a real medical choice.

Anatomical knowledge

Even more surprising: the patient, who died around the age of twenty, seems to have survived between six and nine years after the intervention, according to the signs of bone repair, observable under a microscope.

It is also unlikely that the amputation was performed as a punishment, as the child (or young adolescent) appears to have received careful treatment after the surgery, and at the burial.

"This presupposes an in-depth knowledge of human anatomy, the muscular and vascular system", analyzes the study.

The people who operated on the young teenager had to "regularly clean, disinfect and dress the wound" to prevent any post-operative bleeding or infection that could lead to death.

The physical state of the young amputee, diminished and dependent, also probably forced those around him to take care of him for six to nine years, testifying to an altruistic behavior among this group of hunter-gatherers.

This work "sheds new light on the care and treatment provided in the distant past, and upsets our view that these questions were not taken into consideration in prehistoric times", reacted Charlotte Ann Roberts, archaeologist at the British University. of Durham, in a commentary accompanying the study.

In terms of surgery, there are many prehistoric traces of trepanation or pulling of teeth.

But those of limb amputations are extremely rare, as they are difficult to identify on poorly preserved bones.

After the discovery of Borneo, many questions remain unanswered: how did they proceed?

Was the practice common?

How did they relieve the pain?

In the tropics, the rapidity of infections may have spurred the development of antiseptic products that exploit the medicinal properties of Borneo's rich vegetation, the authors argue.

They also suggest the use of a cut stone blade to operate.

New excavations are scheduled next year in the cave of Liang Tebo, with the hope of learning more about the humans who populated it.

“The conditions are in place for amazing new discoveries in this + hot spot + in human evolution”, assures Renaud Joannes-Boyau, associate professor at Southern Cross University (Australia), who helped date the skeleton.

© 2022 AFP