Trephinations to Craniotomies: Early Innovations in Neurosurgery

In 1892, a 26-year-old patient with a suspected brain tumor underwent four trephinations over the precentral gyrus. The initial procedure was both unsuccessful and detrimental to the patient’s outcome. Eight days later, she suffered a brain herniation, which led to new, large bone resection that was anterior to the previous one. During subsequent trephinations, her superior sagittal sinus was ripped, and ultimately only part of the tumor was successfully resected.

As far back as 6000 B.C. and as recently as the 19^th century, trephinations in which skull openings remained opened were the sole approach to alleviate neurological conditions. Today’s neurosurgeons still perform trephinations to diagnose, relieve pressure and/or create ports for therapeutic interventions.

The Surprising Success Rates of Ancient Trephinations

In 1865, archeologist Ephraim George Squier was given a skull from an Incan burial ground as a gift. But he soon noticed something strange – a hole roughly the size of a half-inch square had been cut out of it.

What’s more, this hole did not appear to be caused by an injury but rather seemed to be the result of a deliberate surgical procedure. Wanting to know more, Squier brought the skull to Paul Broca, Europe’s leading authority on the human skull at the time. Upon further examination, Broca and his colleagues determined that the hole was caused by trephination.

Trephinations are thought to be the most common type of procedure found in archeological material, according to Ortner, 2003, as cited by Lewis, 2018. Research has uncovered five methods of trephination over the centuries: scraping, bore and saw, sawing, drilling, and gouging, each of which vary by the amount and depth of bone removed, according to Arnott et al, 2003, as cited by Lewis, 2018.

In 18^th century Europe, trephination had been used to treat epilepsy and mental illness, with the idea that this would allow evil vapors and humors to escape. By the Renaissance through the beginning of the 19^th century, trephination was largely used to treat depressed fractures and penetrating head wounds.

Interestingly, trephination success rates varied greatly over the centuries. “In Incan times, the mortality rate was between 17% and 25%, and during the Civil War, it was between 46% and 56%. That’s a big difference,” says neurologist David Kushner of the University of Miami Miller School of Medicine. “The question is how did the ancient Peruvian surgeons have outcomes that far surpassed those of surgeons during the American Civil War?”

During the 19^th century, when there was not mainstream use of antisepsis and prophylaxis to counter risk of infection, the mortality rate of trephination was so risky that the first requirement for the operation was thought to be “that the wound surgeon himself must have fallen on his head.”

The First Craniotomy

Wilhelm Wagner, a German physician who had self-trained in surgery, believed that the existing method of trephination was a form of mutilation because it involved resecting healthy cranial bone, and therefore “deprived the brain from its mechanical protection.”

He performed the first modern craniotomy in 1889: a temporary cranial resection to treat intracranial pathology. After practicing on corpses, he used his technique to remove a patient’s post-traumatic epidural hematoma, the first surgery of its kind.

Although the patient died 24 hours post-surgery, Wagner was able to confirm that his method of using an omega-shaped incision to create an osseous musculocutaneous flap was able to provide a good nutrient supply, and his osteoplastic method for cranial opening did not exceed the difficulty or danger of an exploratory laparotomy. This technique, he reasoned, would also work well for brain tumor and abscess removals, and the carrying out of cortical resections in epilepsy.

The Evolution of Craniotomy Techniques

Wagner insisted upon the use of bone resection with a chisel and mallet, claiming that he had never observed any negative outcomes using this technique that could be related to blows from the mallet. But this technique was further improved in 1897 with the flexible twisted Gigli saw, which could be used to join several burr holes together to create the cranial opening.

As techniques improved, indications for craniotomies began to shift from that of cranial fractures, hemorrhagic complications and epilepsy to intracranial tumors. By the early 20^th century, craniotomy techniques expanded even further to involve radiographic or radioscopic equipment and rudimentary mechanical stereotactic systems that were fixed to the skull.

In 1903, Fedor Krause developed a new suction method using an ampoule that would allow surgeons to remove tumors without having to use their fingers, as was common practice at the time.

Decades later, Harvey Cushing worked to isolate and classify the most frequent types of tumors at the time, as well as define the most suitable neurosurgical treatment for each type. Prior to Cushing’s research, just 5% to 10% of diagnosed tumors were considered operable, and the average post-operative mortality rate was thought to be anywhere from 30% to 50% during the first few decades of the 20^th century.

But through his use of palliative surgery such as cranial decompressions and subtotal tumor resections, as well as his intraoperative monitoring of arterial pressure and heart rate, Cushing was able to reduce these rates to less than 13%.

Introduction of Minimally Invasive Neurosurgery

But despite innovations, brain tumors often could not be found or were inoperable in a significant number of patients for decades. In 1971, Donald H. Wilson sought to correct this problem through the development of the “keyhole surgery,” a minimally-invasive surgical procedure to increase precision while reducing the size of the craniotomy, thus minimizing the time of the cranial opening as well as any related complications.

While keyhole surgeries have some limitations and can carry risk, recent studies have shown that it can be an effective method of removing brain tumors. Surgeons were able to remove 90% to 100% of frontal gliomas in 73% of patients using the keyhole craniotomy technique, and were able to achieve a gross total resection in 50% of patients, with the median extent of resection being 98%, according to a 2018 study published in Neurosurgery.

Check out the history of other medical advances and innovations:

Glasgow Coma Scale: How We Got Here

Milestones in the History of External Ventricular Drainage

Intracranial Pressure: The Early Pioneers