More ancient skulls bearing
evidence of trepanation -- a telltale hole surgically cut into the
cranium -- have been found in Peru than the combined number found in the
rest of the world.
Credit: University of Miami
Even with a highly skilled
neurosurgeon, the most effective anesthesia, and all the other advances
of modern medicine, most of us would cringe at the thought of undergoing
cranial surgery today.
After all, who needs a hole in the head? Yet for thousands of years,
trepanation -- the act of scraping, cutting, or drilling an opening into
the cranium -- was practiced around the world, primarily to treat head
trauma, but possibly to quell headaches, seizures and mental illnesses,
or even to expel perceived demons.
But, according to a new study led by the University of Miami Miller
School of Medicine's David S. Kushner, M.D., clinical professor of
physical medicine and rehabilitation, trepanation was so expertly
practiced in ancient Peru that the survival rate for the procedure
during the Incan Empire was about twice that of the American Civil War
-- when, more three centuries later, soldiers were trepanned presumably
by better trained, educated and equipped surgeons.
"There are still many unknowns about the procedure and the
individuals on whom trepanation was performed, but the outcomes during
the Civil War were dismal compared to Incan times," said Kushner, a
neurologist who has helped scores of patients recover from modern-day
traumatic brain injuries and cranial surgeries. "In Incan times, the
mortality rate was between 17 and 25 percent, and during the Civil War,
it was between 46 and 56 percent. That's a big difference. The question
is how did the ancient Peruvian surgeons have outcomes that far
surpassed those of surgeons during the American Civil War?"
In their study published in the June issue of World Neurosurgery,
"Trepanation Procedures/Outcomes: Comparison of Prehistoric Peru with
Other Ancient, Medieval, and American Civil War Cranial Surgery,"
Kushner and his co-authors -- biological anthropologists John W. Verano,
a world authority on Peruvian trepanation at Tulane University, and his
former graduate student, Anne R. Titelbaum, now of the University of
Arizona College of Medicine -- can only speculate on the answer.
But hygiene, or more accurately the lack of it during the Civil War,
may have contributed to the higher mortality rates in the later time
period. According to the study, which relied on Verano's extensive field
research on trepanation over a nearly 2,000-year period in Peru and a
review of the scientific literature about trepanation around the world,
Civil War surgeons often used unsterilized medical tools and their bare
fingers to probe open cranial wounds or break up blood clots.
"If there was an opening in the skull they would poke a finger into
the wound and feel around, exploring for clots and bone fragments,"
Kushner said, adding that nearly every Civil War soldier with a gunshot
wound subsequently suffered from infection. "We do not know how the
ancient Peruvians prevented infection, but it seems that they did a good
job of it. Neither do we know what they used as anesthesia, but since
there were so many (cranial surgeries) they must have used something --
possibly coca leaves. Maybe there was something else, maybe a fermented
beverage. There are no written records, so we just don't know."
Whatever their methods, ancient Peruvians had plenty of practice.
More than 800 prehistoric skulls with evidence of trepanation -- at
least one but as many as seven telltale holes -- have been found in the
coastal regions and the Andean highlands of Peru, the earliest dating
back to about 400 B.C.
That's more than the combined total number of
prehistoric trepanned skulls found in the rest of the world. Which is
why Verano devoted an entire book, Holes in the Head -- The Art and
Archeology of Trepanation in Ancient Peru, to the 800-plus skulls, most
of which were collected from burial caves and archaeological digs in the
late 1800s and early 1900s and reside in museums and private
collections today.
It's also why Kushner, a medical history buff and Tulane alumnus,
jumped at the chance to join Titelbaum in co-authoring one of the book's
chapters, "Trepanation from the Perspective of Modern Neurosurgery,"
and continues to research the subject.
Published in 2016, the book analyzes the techniques and survival
rates of trepanation in Peru through the demise of the Incan Empire in
the early 1500s. The researchers gauged survival by classifying the
extent of bone remodeling around the trepanned holes, which indicates
healing. If there was no evidence of healing the researchers assumed the
patient died during or within days of the surgery. If the margins of
the trepanation openings showed extensive remodeling, they considered
the operation successful and the patient long-lived.
Those classifications, Kushner, Verano and Titelbaum reported in the World Neurosurgery paper,
show how ancient Peruvians significantly refined their trepanation
techniques over the centuries. They learned, for example, not to
perforate the protective membrane surrounding the brain -- a guideline
Hippocrates codified in ancient Greece at about the same time, 5th
century, B.C., that trepanning is thought to have begun in ancient Peru.
The long-term survival rates from such "shallow surgeries" in Peru
during those early years, from about 400 to 200 B.C., proved to be worse
than those in the Civil War, when about half the patients died. But,
from 1000 to 1400 A.D., survival rates improved dramatically, to as high
as 91 percent in some samples, to an average of 75 to 83 percent during
the Incan period, the study showed.
"Over time, from the earliest to the latest, they learned which
techniques were better, and less likely to perforate the dura," said
Kushner, who has written extensively about modern-day neurosurgical
outcomes. "They seemed to understand head anatomy and purposefully
avoided the areas where there would be more bleeding. They also realized
that larger-sized trepanations were less likely to be as successful as
smaller ones. Physical evidence definitely shows that these ancient
surgeons refined the procedure over time. Their success is truly
remarkable."
Almost as remarkable is how, by the end of World War I, cranial
surgery evolved into the distinct profession of neurosurgery, which
continues to improve our understanding of brain anatomy,
physiology and
pathology. As Kushner notes, today's neurosurgeons regularly cut into
the brain to remove tumors and blood clots, reduce intracranial pressure
from massive strokes and trauma, repair vascular and structural
anomalies and treat a myriad of other complex problems -- with great
success.
"Today, neurosurgical mortality rates are very, very low; there is
always a risk but the likelihood of a good outcome is very high," he
said. "And just like in ancient Peru, we continue to advance our
neurosurgical techniques, our skills, our tools, and our knowledge."
