The first neurosurgery performed was “trephination”, which means making a burr hole into the skull. It was first performed in France in 6500 BC! Prehistoric skulls from that time show evidence of burr holes.
Why was it performed? No one knows for sure, but it may have been considered a treatment for mental illness, migraines, or seizures. When skulls from that period are examined, 5-10% have had trephination performed.
While some of the surgeries performed appear to have killed the patient, some of the skulls show evidence of healing, so we know that some of the patients survived!
Skull with trephination performed: