Trepanation (also known as trepanning, trephination, or trephining) is a form of Surgery in which a hole is drilled or scraped into the Skull, leaving the membrane around the Brain intact. It addresses health problems that relate to abnormal Intracranial pressure.
However, there are dubious advocates who suggest trepanation even for healthy people, claiming that after an operation capillaries in the brain should operate on a higher metabolism resulting in a higher state of Consciousness. Some claim spiritual benefits.
Trepanation has been carried out for both medical reasons and mystical practices for a long time: Evidence of trepanation has been found in pre-historic human remains from Neolithic times onwards, per cave paintings indicating that people believed the practice would cure epileptic seizures and mental disorders. Furthermore, Hippocrates gave specific directions on the procedure from its evolution through the Greek age.
Trepanation is generally not practiced by doctors without a medical indication. Illegal in the United States and Europe due to the risk of blood clots, brain injuries and infections, trepanation procedures can lead to Meningitis or Death.