Earliest evidence of ear surgery identified in Neolithic skull

Archaeologists in Spain have unearthed a 5,300-year-old Neolithic skull bearing the earliest known evidence of ear surgery ‘in the history of humankind’.

Since 2016, excavations at the Dolmen of El Pendón in Burgos, Spain, have shed light on a megalithic monument used as a tomb and ossuary during several phases throughout the fourth millennium BC.

Set of cutmarks identifed on the left temporal bone of the skull. The image presents a lateral view of the left side of the skull (a), a detail of the left temporal bone with evidence of surgical trepanation (b), and an enlarged image of the cutmarks around the anterior edge of the trepanation made in the left ear (c). IMAGE: Scientific Reports / Díaz-Navarro, S. et al.

The structure consisted of a funerary enclosure – a chamber formed of large, upright limestone orthostats, only six of which remain standing – and an 8m-long entrance passage, all encircled by a mound of soil and stones measuring around 25m in diameter.

During the monument’s second phase of use (c. 3250 BC), approximately 100 bodies were deposited. Many of the skeletal remains were disarticulated and repositioned, a reflection of the development of new ritual practices which saw the dolmen transformed into a collective ossuary.

A study recently published in the journal Scientific Reports centres on a skull recovered from the site in 2018, which dates to this second phase of occupation.

Analysis of the skull revealed it likely belonged to a women aged 35 or older, as indicated by the heavy decline in bone density and loss of all the maxillary teeth long before death. The most exciting observation, however, was of evidence that ear surgery had been performed on the individual.

Two bilateral perforations on both left and right temporal mastoid bones (located behind each ear) were identified, signifying they underwent a surgical procedure known as a mastoidectomy. This intervention is aimed at treating otitis media and mastoiditis – painful infections of the mastoid bones.

According to the paper, the first procedure was likely conducted on the right temporal bone, which showed signs of an infection ‘sufficiently alarming to require an intervention.’ The hypothesis of surgical intervention is further supported by the presence of seven cutmarks at the anterior edge of the perforation made in the left ear.

The time interval between the two interventions is unclear; however, evident signs of bone regeneration and remodelling around the incisions indicate the individual survived for at least one month following the procedures.

Computed tomography (CT) scans showing the external auditory region on the skull’s right (a) and left (b) temporal bones. A modern skull showing signs of mastoidectomy performed by students of the Faculty of Medicine of the University of Valladolid (c) and example of a skull without any pathologies (d). CT scans at the right middle ear level from the El Pendón skull (e) and from a present-day skull exhibiting no pathologies (f). IMAGE: Scientific Reports / Díaz-Navarro, S. et al.

The skull presents the earliest evidence of ear surgery and, as stated by the researchers, the first known radical mastoidectomy ‘in the history of humankind’.

Prior to this discovery, the earliest osteological evidence of mastoidectomies is from the island of Thassos, and dates to the Proto-Byzantine period (c. 330-824 AD).

A set of lithic tools recovered from the Dolmen of El Pendón were also analysed to identify which techniques and typologies may have been used for the surgery. The team suggests a tool similar to a flint blade found at the site, which showed signs of use for butchering, may have been employed. If so, creating the perforations would have required continuous circular and abrasive drilling.