Saturday, November 14, 2026
Andean Infernal Miracle of Survival
INCA TREPANATION
Surgical technique,
archaeological evidence, and inferred long-term survival
Synthetic
research note by Md. Merajul Islam
Prepared
for Dr Jacques Coulardeau
Revised version: 22 October 2026
PART ONE
Executive
summary
Trepanation (also
spelled trephination) is the deliberate creation of an opening in the cranial
vault by scraping, cutting, or drilling bone. Peru has produced an unusually
extensive archaeological record of this practice. Evidence from the Cuzco
region indicates that cranial trauma was an important indication and that
practitioners used techniques including scraping and circular cutting. Kushner
and colleagues’ 2018 comparative study reported inferred long-term survival of
about 40% in an early Peruvian sample dated 400–200 BCE, up to 91% in samples
dated AD 1000–1400, and 75–83% for the Inca-period sample dated to the
fifteenth century. These are estimates inferred from bone healing, not from
written death records or direct clinical follow-up. [1][2]
The central
methodological point is that a healed trepanation margin indicates survival
long enough for bone remodeling to occur; it does not establish complete
recovery, exact survival duration, original indication, or neurological
outcome. The evidence supports a sophisticated and empirically refined surgical
tradition, while claims about anesthesia, asepsis, routine use of particular
tools, and ritual purpose require cautious wording.
1.
What the procedure was and was not
Trepanation is a
prehistoric and cross-cultural practice, not an Inca invention. Peruvian
evidence predates the Inca state by many centuries. “Craniotomy” should not be
used as a simple synonym: in modern medicine, craniotomy generally means
temporarily removing a bone flap for surgery, whereas archaeological
trepanation refers broadly to making an opening by scraping, cutting, or
drilling. [1][3]
Archaeological
remains can preserve the opening, marks that suggest technique, and evidence of
healing. They rarely preserve the complete operation, including patient
positioning, assistants, wound dressings, pain management, or the
practitioner's intentions.
2.
Techniques and procedural logic
Published
descriptions of Andean trepanation identify scraping/abrasion and circular
cutting or grooving among the principal techniques. Other cranial openings in
the wider Andean and global record were made by drilling or intersecting cuts.
These categories are inferred from marks on bone and should not be presented as
a single fixed sequence used in every Inca operation. [1][2][3]
●
Scalp exposure is likely where the opening was made, but
soft-tissue steps are not directly preserved in dry skulls.
●
Scraping gradually thins the cranial vault; circular grooving cuts
a perimeter around a central bone plug. The opening may preserve traces of the
method.
●
Successful cases are consistent with controlled bone removal and
avoidance of intracranial structures, but exact operative decisions are
inferred rather than documented in an Inca surgical manual.
●
Aftercare is incompletely recoverable. Healed bone proves survival
long enough for biological response, but not the exact dressing, cleaning
regimen, or follow-up.
3.
Instruments, substances, and claims requiring caution
The literature
discusses stone tools, including obsidian, and metal instruments in
pre-Columbian Andean contexts. The tumi is a well-known Andean curved or
semicircular knife, but it should not be asserted that every trepanation was
performed with a tumi. Tool marks and associated artefacts are stronger
evidence than broad generalisations. [3][4]
Coca, datura,
yucca, and chicha appear in secondary descriptions of Andean medicine. Their
use as a standard, controlled anaesthetic regimen for trepanation is not
demonstrated by healed skulls themselves. The cautious formulation is that
plant preparations and fermented drinks may have formed part of broader
therapeutic practice, while exact substances, doses, and use during specific
operations remain uncertain. These practices should not be described as modern
anaesthesia.
Claims that
instruments were routinely single-use, that operations were deliberately
performed outdoors to prevent infection, or that gold cranioplasties were
common require specimen-specific evidence. A critical review found limited
support for claims that cranioplasty was common in ancient Peru. [5]
TO KNOW MORE:
The Incas Beyond Empire and Collapse:
Language, Bodies, and
the Andean Science of Survival
… To Be Continued …
References
References below
identify the principal sources used for this synthesis. Exact numerical claims
should be checked against the full text and tables before publication.
[1] [1] Kushner, D. S., et al.
(2018). “Trepanation Procedures/Outcomes: Comparison of Prehistoric Peru with
Other Ancient, Medieval, and American Civil War Cranial Surgery.” World
Neurosurgery. PubMed: https://pubmed.ncbi.nlm.nih.gov/29604358/ ScienceDirect: https://www.sciencedirect.com/science/article/pii/S1878875018306259
[2] [2] Andrushko, V. A., & Verano, J. W. (2008). “Prehistoric trepanation in the
Cuzco region of Peru: a view into an ancient Andean practice.” American Journal
of Physical Anthropology, 137(1), 4–13. https://doi.org/10.1002/ajpa.20836 PubMed:
https://pubmed.ncbi.nlm.nih.gov/18386793/
[3] [3] Marino, R., Jr. (2000).
“Preconquest Peruvian neurosurgeons: a study of Inca and pre-Columbian
trephination and the art of medicine in ancient Peru.” Neurosurgery. PubMed: https://pubmed.ncbi.nlm.nih.gov/11014434/
[4] [4] American College of
Surgeons. (2022). “Trepanation Reveals the Success of the Incas.” Bulletin,
November–December 2022. https://www.facs.org/for-medical-professionals/news-publications/news-and-articles/bulletin/2022/november-december-2022-volume-107-issue-11/from-the-archives/
[5] [5] Verano, J. W., & Andrushko, V. A. (2010). “Cranioplasty in ancient Peru: a
critical review of the evidence, and a unique case from the Cuzco area.”
International Journal of Osteoarcheology. https://doi.org/10.1002/oa.1028
