Siberian brain surgery techniques dating back 2,300 years have been recreated by scientists looking to find out how doctors carried out these complex operations with primitive tools.

Evidence of brain surgery in ancient Siberia was discovered last year when archaeologists came across three skulls in the Altai Mountains – they belonged to members of the Pazyryk nomadic tribe and showed clear evidence of a process called "trepanation".

This technique involves drilling a hole or scraping into the skull in order to treat victims of head trauma. The hole would help to relieve pressure from brain swelling.

Since then, neurosurgeons have been working with anthropologists and archaeologists to find out more about the method to work out how these early doctors carried out their work, the Siberian Times reports.

Researchers believed the practice showed that either the nomads learned the technique from other parts of the world, or uncovered it at the same time as other doctors in Greece and the Middle East.

Findings showed doctors followed the Hippocratic Corpus, the set of medical ethics set out in Greece in 500BCE – 5,000 miles from the Altai Mountains.

Neurosurgeon Aleksei Krivoshapkin said: "Honestly, I am amazed. We suspect now that in the time of Hippocrates, Altai people could do a very fine diagnosis and carry out skilful trepanations and fantastic brain surgery."

In one of the skulls – a male aged between 40 and 45 – scientists believe the operation was carried out to remove a blood clot from head trauma. Later bone growth suggests he survived and lived for many years after.

Examining the technique, scientists discovered the operations took place in two stages – first a sharp cutting tool was used to remove the surface layer of bone without perforating the skull. After this, short and frequent movements were used to cut into the skull.

Krivoshapkin said: 'All three trepanations were performed by scraping. From the traces on the surface of the studied skulls, you can see the sequence of actions of the surgeons during the operations.

"It is clearly seen that the ancient surgeons were very exact and confident in their moves, with no traces of unintentionally chips, which are quite natural when cutting bone."

The surgeon then performed the operation using the same techniques on modern-day skulls and it took just 28 minutes to complete. Krivoshapkin said it required "considerable effort".

Whether or not the nomadic surgeons used any anaesthetic or painkiller is unknown, and archaeologists are now searching for the dedicated medical tools used to perform the operations.