In 1967 – almost forty years ago – a neurosurgeon from Arequipa, enthusiastic walker and adventurer, Gustavo Rondón Olazábal, discovered a cache of bones in the Andahua and Chachas region (province of Arequipa). Among the scattered bones he made a surprising discovery, several skulls that had been carefully trepanned. This discovery caused him to ask whether there had been neurosurgery in the pre-Inca era. Let him tell his story and describe his conclusions.

How did I find the cementery with the trepanned skulls? In 1967 we were walking on a bridle path between Andahua and Chachas with a view to seeing the famous volcanoes. The first we saw was a small crater covered with bushes. Almost opposite, another small volcano with vegetation growing on it. Near the base was a large pile of blackish volcano rocks. Leaving the depression and entering another, we found a number of human bones in complete disorder, mixed with pieces of plain rough cloth and pieces of broken pottery. This chaos had been left behind by grave robbers.

Our curiosity and professional training made us take a closer look at some of the bones to try to recognize them: ribs, vertebrae, scapulas and long bones from adult’s skeletons. But what most surprised us was a skull with a hole in the posterior parietal region. Without doubt it had been trepanned. We were even more astonished when we found a second skull which had also been trepanned but the fourth had, in the left parietal area; it was also fractured. We collected four trepanned skulls.

I continued to visit the zone and reported the finds on several occasions (at the Alianza Francesa in Arequipa, the UNSA, talks at the Regional Cultural Institute). In Lima, at a meeting of the Peruvian Neurosurgery Society I presented an extended paper with some more skulls that we had collected in further excursions to the area.

I kept returning alone and thus found other graves, also desecrated and always with human remains. I could see an entire town on the flat land next to the little volcano and facing the area of the graves. It had rectangular and circular buildings, some with niches, and streets. What caught my attention was that the town stopped abruptly. This compact town did not appear to have had buildings outside its walls.

I think these finds are important, although I am not an archaeologist, in the light of a certain basic knowledge of Peruvian archaeology regarding trepanning in ancient Peru and my training as a neurosurgeon, I can list the findings and make certain deductions about them:

• This the first time trepanning has been discovered in a spot in southern Peru, specifically in the department of Arequipa.
• All the trepannings were carried out in the same surgical manner, circular trepanning.
• Of the nine trepanned skulls found in the area and subject to a preliminary study, there is no doubt that eight of them show evidence that the person survived the surgery.

My in situ studies and research lead me to important conclusions:

• Andahua contained a very important neurosurgery center in the pre-Inca era. The type of trepannings found all have the same characteristics. Therefore there was once surgery school there.
• Knowledge and skills were passed from tutor to students over many generations. Techniques improved until some notable successes were achieved: prolonged survival after surgery.
• The most numerous operations probably took place on patients brought from other areas.

Therefore the ruins next to the graves were not dwellings, but a sort of specialized clinic, where the surgery took place. The patients remained there for as long as necessary to recover, either fully or partially.

Nevertheless there are many unanswered questions. Among them: Why was Andahua chosen for such a sophisticated neurosurgery center? Did the trepanning have anything to do with the abundant volcanic craters in the zone? Were the volcanoes perhaps magical representations of trepanned skulls? Were they the marks of trepanning carried out by the gods of the Mother Earth? Was Andahua an important place on the route from the coast to Cusco that saw many travelers? Was the development of neurosurgery in this relatively remote zone the result of the efforts of a group of physicians led by a great master of neurology now forgotten?

These and other questions cannot be answered easily. Nevertheless, through modern technology still not available to us, we may in time be able to confirm suspicions.