Rachel Kalisher, a PhD student at Brown University, works on site in Tel Megiddo, Israel (Photo: PA)

The earliest evidence of an “unusual” type of brain surgery performed sometime in the 15th century was unearthed by archaeologists in Israel.

Scientists have examined the remains of two people believed to be brothers, buried in a tomb at the Tel Megiddo archaeological site.

One of the skulls has a 30mm square hole in the frontal bone where a piece was surgically removed in an ancient medical procedure known as trepanation.

While this procedure is believed to have existed for thousands of years, experts say this type of trepanation is the earliest example of this type in the ancient Near East, which includes western Asia, southeastern Europe, and northern Africa.

Doctors today perform a similar procedure known as a craniotomy to treat tumors or blood clots or to remove foreign bodies such as bullets.

One of the skulls has a 30mm square hole in the frontal bone where a piece was surgically removed in an ancient medical procedure known as trepanation (Photo: PA).

“We have evidence that trepanation has been this universal, widespread form of surgery for thousands of years,” said Rachel Kalisher, a doctoral student at Brown University’s Joukowsky Institute for Archeology and the Ancient World.

“But we don’t see it that often in the Middle East — there are only about a dozen examples of trepanation in this region.”

Scientists believe one of the brothers had a specific type of cranial surgery called angular indentation trepanation.

The procedure involves cutting four intersecting lines into the skull and using leverage to create a square hole.

Experts believe that this kind of medical treatment was rare in the region and only accessible to the elite.

Analysis of the bones suggests that both brothers suffered from some form of chronic illness.

Doctors today perform a similar procedure known as a craniotomy to treat tumors or blood clots, or to remove foreign bodies such as bullets (Photo: PA)

“These brothers were clearly living under quite intense pathological conditions that would have been hard to bear in modern times without wealth and status,” Kalisher said.

The researchers believe the upper-class brothers lived in Megiddo around the 15th century.

Their tombs were decorated with high-quality food and pottery, similar to other high-ranking tombs in the area.

One of the brothers is said to have died in their teens or early twenties, the other somewhere between their twenties and forties, both possibly from an infectious disease.