What is interesting about trepanning?

1. There is about a 70% chance of survival although the surgical operation didn't usually cause death but the infection afterwards

2. The process took roughly 30-60mins to complete

3.

The tools commonly used in trepanning included a sharp knife, which is used to cut through the skin of the skull and made it possible to pull back the flaps, and a borer similar to a corkscrew. Surgeons also use brushes and files to tidy up the final area around the hole.