A Hole in the Head: The Ancient Surgery of Trepanning

Detail from The Extraction of the Stone of Madness, a painting by Hieronymus Bosch depicting trepanation (c.1488–1516).

Trepanning (aka trephining) is a procedure wherein a hole is cut in the skull, exposing the brain. Discover evidence of this ancient and mysterious practice

It is believed that trepanning was first practised at least 7000 years ago. Evidence of trepanning at this time takes the form of stone-age skulls that have obviously undergone this procedure. Trepanning was not a rare practise at this time. For example, in one gravesite in Northern France, one hundred and twenty skulls were found, forty of which showed evidence of trepanning (however, this is an unusually high proportion).

Characteristics of Stone-Age Trepanning

Trepanning was carried out on men, women and children, although the majority of trepanned skulls discovered are those of adult males. Trepanning was also performed on corpses, as well as the living. The size of the holes found in skulls varies between cultures. For example, skulls in Bulgaria have been found containing miniscule holes of approximately 2mm in diameter, wheras other skulls have been discovered containing holes up to 2 inches across.

Amazingly, the majority of people who underwent trepanning seem to have survived for some time after the procedure, as the bone shows evidence of regeneration. This is particularly impressive when you consider the primitive tools that ancient humans would have used, such as flint knives and bow drills made of wood and tipped with very hard material.

Reasons for Trepanning

The reasons for ancient trepanning remain uncertain, although some skulls show evidence of the procedure being carried out after a head injury. It is also thought to have been used to treat mental illness, epilepsy, and even headaches (which seems rather extreme!). It is thought that Stone Age people believed they were allowing bad spirits to escape from the skull, or allowing good spirits to enter.

Another possible motive for some cases of trepanning is the acquisition of rondelles (discs of bone obtained by cutting circular holes in skulls). These are thought to have been used as charms or talismans, to protect the keeper from accidents and disease.

Modern Trepanning

Trepanning is still carried out today in parts of Africa and South America. It is also used in western medicine (the term “craniotomy” is usually used instead of trepanning) to treat cases of head injury, as it can relieve the pressure from fluid or blood build-up, and allow the insertion of monitoring devices. However, the bone is usually replaced afterwards.

Some people advocate voluntary trepanning to stimulate brain activity. The ITAG (International Trepanation Advocacy Group) believes that the process favourably alters the movement of blood through the brain and improves brain functions. According to the ITAG, the enhanced blood flow after trepanning resembles the blood flow characteristics of youth, and some people who have undergone trepanning claim that the process leaves them feeling like a child, full of energy and free of stress.

However, finding a surgeon to perform voluntary trepanning is no mean feat. The benefits are uncertain (people who report improvements in their mental functioning and wellbeing may simply be experiencing a placebo effect) and the risks include blood clots, stroke, meningitis, epilepsy, and bone fragments becoming embedded in the brain during the surgery. The idea of voluntary trepanning has been referred to by various doctors as “quackery”, “pseudoscience”, “nonsense” and some much ruder words.

Peter Halvorson

In 1972, a jeweller from Pennsylvania named Peter Halvorson decided to attempt trepanning himself. He attached an electric power drill to his bathroom ceiling and proceeded to drill through his skull. Fortunately, he survived, and believes that his experience has given him greater energy, drive and focus. Assuming that your interest in this article is purely academic, a “don’t try this at home” warning is probably unnecessary.


  1. Halverson, Peter (Date unknown). “ITAG: International Trepanation Advocacy Group”. Trepan.com.
  2. Traversi, Christine (2002). “Being Made Hole”. Serendip.brynmawr.edu.