AIR IN THE BRAIN
When looking for tumors, abscesses, and other lesions of the brain, physicians today turn to CT and MRI scans. That was not always the case. In the nineteenth century, a careful history and neurologic examination provided the only means available to diagnose and to localize such lesions. Since only the rare surgeon ventured into the cranial cavity without more concrete information, it was the autopsy, not surgery, that confirmed the clinical findings.
The discovery of X-rays in 1895 brought hopes of easier diagnosis, but the hopes foundered when tumors, brain tissue, and fluids all appeared gray, lacked contrast, and were indistinguishable. One surgeon lamented that the brain was still “a dark continent.” A possible solution was to introduce an agent that provided enough contrast on X-ray to demarcate a lesion. At Johns Hopkins Hospital, a rising neurosurgeon, Walter Dandy, tried several contrast agents that urologists used to visualize the bladder and ureters on X-ray, but in animal trials they were all too toxic to brain tissue. It was
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| Walter Dandy (Wikipedia) |
common knowledge, though, that air appeared darker than soft tissue on X-rays. Why not introduce air into the ventricular system to provide the contrast?
To accomplish this, a knowledge of the circulation of spinal fluid, the clear fluid that fills the ventricles and circulates over the entire brain, was necessary. Fortunately, Dandy had recently worked out the fluid dynamics in animal studies done in the Hunterian Laboratory at Hopkins. (The original name for the laboratory was the Magendie Laboratory but, after vociferous demonstrations by antivivisection activists, “Hunterian” replaced it.)
Dandy began with children, primarily ones with hydrocephalus, injecting air directly into the ventricles through the still open space between fontanelles on top of the cranium. He needed to withdraw an equal amount of fluid to avoid changes in pressure, a tricky balancing act. His first paper on pneumoencephalography (PEG), as it came to be called, was in 1918. Soon after, he tried introducing air by lumbar puncture into the fluid-filled space around the spinal cord and published satisfactory results. This technique required rotating the patient in various ways, not all comfortable, to allow the air to move up the spine into the desired areas of the brain. He did not pursue the spinal approach, however.
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| Dandy's first X-rays using air to visualize the ventricles. Here, the contrast is reversed, the air a lighter shade. (Hathi Trust) |
A year or two later, in Braunschweig, Germany, Adolf Bingel, chief of Internal Medicine at the Braunschweig Hospital, aware of work in Norway (and unaware of Dandy’s publications) using air
through the spinal route to see spinal tumors, adopted the lumbar approach. He noticed by chance that a patient, X-rayed the day after air was introduced spinally, showed air in the cranium. Trials on cadavers confirmed this route to the brain. Like Dandy, he showed that the air could outline the ventricles and provide contrast over the brain surface. His main concern about the spinal approach was that if the fluid pressure above grossly exceeded that from below, the stem of the brain could be squeezed, a life-threatening possibility. To avoid this, Bingel devised an apparatus to ensure that the spinal fluid pressure remained stable during the procedure, an important step (see illustration). He became aware of Dandy’s work with the lumbar approach only after his own first publication. Meanwhile, Dandy had returned to the ventricular approach, allegedly fearing potentially dangerous pressure differentials. Bingel, on the other hand, feared the direct ventricular injection approach, having lost two patients after using it.
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| Frontal view of ventricles from paper by Bingel (Hathi Trust) |
Adolf Bingel appears to be an underappreciated innovator. Born in 1879 in Koblenz to a coal-and-wine-merchant father and the daughter of the famous guidebook publisher Karl Baedecker, he studied medicine at the University of Tübingen. He worked in academia in various places and was finally appointed chief of the medical service at the Braunschweig Hospital, a teaching hospital. He had already done research on blood pressure measurement and renin physiology and took up research on leukemia, syphilis therapy, pernicious anemia, neurologic problems, and more. He was a pioneer in needle biopsy of the liver as early as the 1920s. Over a period of 30 years, he conducted three blinded controlled trials of diphtheria antitoxin vs horse serum and found them equivalent, a controversial conclusion. It was at the Braunschweig Hospital, in the chaotic years after WWI, that Bingel began pneumoencephalography. He remained there through WWII, dying in 1953.
In early days physicians removed most of the spinal fluid, replacing it with air. This produced severe headache and nausea, sometimes requiring anesthesia, and there were occasional fatalities. Understandably, pneumoencephalography was not widely accepted. In the 1930s the radiologist Cornelius Dyke and the neurosurgeon Leo Davidoff, at the Neurological Institute affiliated with Columbia-Presbyterian Hospital in New York, found that smaller amounts of air provided equally satisfactory imaging results. Fewer side effects and improved safety led more physicians to adopt the procedure, though it was still not risk-free.
To ease the distribution of air into the ventricles and over the brain surface, moveable chairs were devised that could move the patients into almost any position. They bore the interesting name of “somersault chairs,” and indeed, using a side arm, tilted the strapped-in patient into bizarre positions, maneuvers that made some radiologists nervous. Headache and vomiting were still common.
The 1950s brought change with the introduction of angiography, followed by CT scanning in the 1970s, then MRI scanning. Compared to the new scanning techniques PEG seemed quite primitive and the difficult and potentially dangerous technique quickly passed into the realm of interesting historical curiosities and medical history blogs.
SOURCES:
Marmaduke, M E, et al, Walter Dandy: The Personal Side of a Premier Neurosurgeon, 2002; Lippincott Williams & Wilkins.
Dandy, W E, “Ventriculography Following the Injection of Air into the Cerebral Ventricles.” Ann Surg 1918; 63 (1): 5-11.
Müller, J, et al, “Adolf Bingel, the Second Inventor of Lumbar Pneumoencephalography.” Amer J Neuroradiol 1995; 16: 487-90.
Kieffer, S A, “Cornelius G Dyke and the Neurological Institute of New York: The Foundations of American Neuroradiology.” Amer J Neuroradiol 1997; 18: 801-9.
Hoeffner, E G, et al, “Neuroradiology Back to the Future: Brain Imaging,” Amer J Neuroradiol2012; 33: 5-11.
Trohler, U, “Adolf Bingel's Blinded, Controlled Comparison of Different Anti-diphtheritic Sera in 1918,” J Roy Soc Med 2011; 104 (7): 302-5.
