Evidence of trephination has been seen through the analysis of excavated skulls.
From the en.wikipedia.org
Over 8000 years ago, we have evidence of trephination, a procedure in which a hole was bored in the skull to free the evil spirits trapped inside.
From the huffingtonpost.com
Trephination was a primitive skull surgery used by the Nazca that relieved pressure on the brain from battle wounds or for ritual purposes.
From the en.wikipedia.org
His Anathomia provides pictures of neuroanatomical structures and techniques such as the dissection of the head by means of trephination, and depictions of the meninges, cerebrum, and spinal cord.
From the en.wikipedia.org
More examples
An operation that removes a circular section of bone from the skull
Trepanning, also known as trephination, trephining or making a burr hole, is a medical intervention in which a hole is drilled or scraped into the human skull, exposing the dura mater in order to treat health problems related to intracranial diseases. ...