Prehistoric trepanation in this part of South America consisted of four techniques, the scientists say. Practitioners cut out squares of bone, bored holes in the skull, scraped away bone to create an opening or made circular incisions to remove a plug of bone. Inca surgeons specialized in the latter two methods. Excavations, however, have not yielded trepanation instruments.
In pre-Inca times, only one-third of skull surgery patients survived the procedure, as indicated by short- or long-term healing around cranial openings. Survival rates rose to between 80 and 90 percent during the Inca era, from A.D. 1400 to 1532. Few skulls showed signs of infection near surgical holes.
Okay, I was expecting yet another "WOW, look at what these ancient people did!" story, but it's based on a paper in the AJPA so there's a bit more there than yer average gee-whiz article on trepanning.