A human skeleton has provided evidence of the earliest known limb amputation after its foot was found to have been surgically removed.
Researchers in Borneo also determined the patient, who would have been alive about 31,000 years ago, had the limb amputated as a child and recovered from the procedure.
The researchers said the discovery on the island shows human foraging groups in tropical Asia had sophisticated medical knowledge and skills, including on how to prevent infection.
Writing in the journal Nature, Tim Maloney, from Griffith University in Australia, and colleagues said the human skeleton is of a young person.
They survived the procedure and lived for another six to nine years before being buried in Liang Tebo cave in East Kalimantan.
The area contains some of the world’s earliest dated rock art.
Until now, treatment of people with illness or injury was thought to have been poorly developed among small-scale foraging communities.
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It was believed they could manage smaller procedures such as suturing and dentistry.
“The prevailing assumption has been that more complex surgeries were beyond the abilities of foraging societies past and present,” the authors said.
They added: “Before modern clinical developments, including antibiotics, it was widely thought that most people undergoing amputation surgery would have died, either at the time of amputation from blood loss and shock or from subsequent infection-scenarios that leave no skeletal markers of advanced healing.”
The experts said the surgeon who carried out the amputation on the child “must have possessed detailed knowledge of limb anatomy and muscular and vascular systems to prevent fatal blood loss and infection”.
They added that “intensive post-operative nursing and care would have been vital”, including regularly cleaning the wound and dressing it “perhaps using locally available botanical resources with medicinal properties to prevent infection and provide anaesthetics for pain relief”.
The experts continued: “Although it is not possible to determine whether infection occurred after the surgery, this individual evidently did not suffer from an infection severe enough to leave permanent skeletal markers and/or cause death.”
The skeleton had “remodelled bone” covering the “amputation surfaces”, which shows there was healing after the operation.
The authors also suggested the amputation was unlikely to have been caused by an animal attack or other accident, as these typically cause crushing fractures.
The amputation was also unlikely to have been carried out as a punishment, as the person seems to have received careful treatment after surgery and in burial.
Until now, the oldest known complex operation was carried out on a Neolithic farmer from France about 7,000 years ago. His left forearm was surgically removed and then partially healed.