A review of new research is presented in Nature Precedings regarding a skull radiocarbon dated to 1940 calBC (late Neolithic – early Bronze Age) from Germany, which exhibits signs of trephination.
The authors say:
The skull fragment includes large parts of the cranial vault including both frontal bones down to the left orbital rim, the right parietal, and both occipital regions. The whole cranial base as well as the facial bones and the left temporal regions are missing. It is the only part left of the original skeleton of an adult male. The skull fragment shows two manipulations: In the left frontal-region one notes a hole with a diameter of 30 x 25 mm which results from a funnel-shaped trephination with the outer size of 53 x 50 mm. The diameter of the rim varies from 10 12 mm. The diploe of the bone is not visible which means that the trephination must have been survived for a longer period of time. The configuration of the defect and the angulation of its edge indicate that the trephination was performed by the scraping-technique. A second defect involves the left occipital region partially crossing the lambdoid suture. It consists of two small and one larger skull fragments which have grown together forming a typical consolidated depressed skull fracture. The depth of the defect is approximately 10 mm at its maximum. Its diameter measures 35 x 24 mm.
They speculate that the individual received two simulataneous injuries, one of which was trephined whilst the second healed without medical intervention. However, as they note, two chronologically differing traumatic incidents are possible of which only one was severe enough to be in need of surgical measures. Alternatively, the intact skull may have been trephined in the left frontal region because of the temporo-occipital injury to prevent complications, e.g. a suspected haematoma under a local bruise of the skin.
Reference: Piek, Juergen, Lidke, Gundula, and Terberger, Thomas. Ancient Trephinations in Neolithic People – Evidence for Stone Age Neurosurgery?. Available from Nature Precedings <http://hdl.handle.net/10101/npre.2008.1615.1> (2008)