Neurosurgery, in a sense, has been around for centuries. The oldest evidence of purposeful “surgery” on the skull is over 10,000 years old1. In fact, we know from the Edwin Smith Papyrus2 that the Egyptians practiced rather sophisticated neurosurgery 2000 years before the birth of Christ. The 1913 expedition of Dr. Ales Hrdlicka3 in Peru provided proof of pre-Columbian neurosurgery in the New World. Subsequently, archeologists have found signs of neurosurgery at digs throughout most of the world. Neurosurgery performed during the 19th century was done only as a last resort and most often with disastrous consequences. During the 20th century, however, neurosurgeons have achieved important improvements to both technique and diagnosis.
Early 20th Century
Most would agree that many of the early advances in neurosurgery during the 20th century can be attributed to Harvey Cushing, MD. After witnessing procedures in Europe, Dr. Cushing developed meticulous techniques based on Halsteadian principles to perform surgery on the brain. Among the many diagnostic and technical advancements made at his hands or provocation, include the development of the anesthesia record; introduction of blood pressure apparatus (Riva-Rocci) in the U.S.; introduction of the pneumatic tourniquet for the control of scalp bleeding during craniotomy; development of vascular clips to control bleeding; and the emergence of electrosurgical techniques (Bovie). Many of the instruments Dr. Cushing invented have changed little over the years, and can still be found bearing his name in various instrumentation catalogues.
The Influence of Walter Dandy, MD. Dr. Cushing wasn’t the only neurosurgeon making advances in the specialty during the early 1900s. Where Dr. Cushing’s focus was on technique, Walter Dandy’s, MD, innovations were related to technology.
Dr. Dandy’s4 contributions include the use of myelography, pneumoencephalography and pneumoventriculography, and the wide usage of the radio knife for cautery and surgical dissection. He worked extensively with patients suffering from herniated intervertebral discs, gliomas, Meniere’s syndrome, trigeminal neuralgia, pituitary adenomas, meningiomas, and hydrocephalus. His research interests were varied from chordoid plexus to the development of the first protective baseball cap.
What lessons can be drawn from these two medical professionals? They were men living on the cusp of great leaps in technology. More important, they were medically and mechanically astute. When they wanted to perform a maneuver during surgery and did not have an instrument to do it gracefully, they had the ability to design something that would.
When they did not have the diagnostic capability to verify the exact location of a tumor prior to surgery, they worked with inventors who could develop the equipment to insure a more appropriately focused surgical field. Additionally, they lived in a time when innovations were coming about in all areas of medicine and public hygiene that helped increase public awareness.
Technological Explosion
By mid century, neurosurgery had undergone a metamorphosis and was entering new dimensions. Methods of anesthesia, sterilization, and hemostasis were emerging. The electroencephalogram found acceptance as a localization technique. Nuclear medicine techniques were identified and advances in this area were made. Stereotactic neurosurgery emerged as a less-invasive surgical procedure. Microsurgery vastly improved patient outcomes, and angiography and other imaging techniques were developed to better assist surgeons. Clearly, it is difficult to cite all of the advances in neurosurgery in the latter half of this century. However, the following overview provides a glimpse at some of the dramatic advances that have shaped this ever-expanding field.
Electroencephalography. Although proof was found in 1875 that electrical current originates from the cerebral cortex5, it wasn’t until 1935 with the published results of electroencephalography (EEG) research that it came to be accepted as the primary diagnostic tool in certain epileptic disorders and some brain tumors. The emergence of this localization technique enabled neurosurgery to broaden its scope and efficiency, while increasing the safety of many procedures.
It is interesting to note that there were problems with early EEG machines picking up static and background noise (i.e. Wilder Penfield, MD, was able to pick up music on an EEG in 19386). By 1944, it was determined that nearly 60 percent of tumors could be localized correctly using EEG7–this has given way to other imaging techniques, but its importance as a diagnostic tool for epilepsy remains.
Nuclear Studies. Research at the University of Minnesota in 1947 found that fluorescein will permeate abnormal brain tissue, allowing needle biopsies of suspected tumors to be verified under ultraviolet light. In addition, advances made during the 1950s and 1960s utilized many non-harmful types of radioisotopes to identify the type and location of brain tumors.
Detection of the gamma rays emitted by radioisotopes was accomplished by an evolution of scanners, beginning with a Geiger-Müller tube in 1948 and resulting in the development of the rectilinear brain scanner in1951, scintillation camera in 1958, and the development of the Positron-Emission Transaxial Tomogram (PET) scanner in 1975.
Moreover, the advent of the Computerized Axial Tomography (CAT) scanner in 1970 and Magnetic Resonance Imaging (MRI) in 1981 vastly improved pathology localization techniques.8
Stereotactic Neurosurgery. Over the past 80 years, stereotactic surgery has progressed from an innovation in the laboratory study of neuroscience, to an ever-increasing part of the practice of neurosurgery. The now burgeoning field of human stereotactic surgery, and its rapid rate of progress, has often been dictated by developments in other clinical and non-clinical fields, such as radiology, neurophysiology, electronics, metallurgy, and more recently, advances in neuropathology, computer science, CAT scanning, and MRI. In the near future, similar advances are expected in neuropharmacology and embryology.9
The first procedure on a human using a stereotactic instrument was performed in 1933, and involved thermal coagulation of the human gasserian ganglion to treat trigeminal neuralgia.10 The first stereotactic instrument routinely used in human neurosurgery was named the stereoencephalotome, and was first described in 1946. In addition to utilizing the stereoencephalotome for the then popular lobotomy, its designers suggested that it should also be considered for the interruption of pain pathways, treatment of movement disorders, and for the “withdrawal of fluid from pathological cavities and cystic tumors.” They published their first Stereotactic Atlas in 1952.11
During this time, parallel research also was taking place in Stockholm and Paris. It was this research that led to the development of four major types of stereotactic frame systems. By 1982, stereotactic surgery was taken to the next level, and the first “frameless stereotactic surgery” utilizing CT scans was proposed. Subsequently, a frame was adapted for MRI imaging in stereotactic neurosurgery in 1985.12
Microneurosurgery. The first operation on a human using a surgical microscope was performed in 1957 on a 5-year-old girl who had a rare condition of Schwann cell tumor with total facial palsy.13 The evolution of the surgical microscope was necessary to develop the mobile, counter-balanced surgical microscope in use today. The surgeon requires training in a specially-equipped laboratory and must master indirect eye-hand coordination.14
The advent of microsurgery required new studies to reveal previously unreported details of neuroanatomy.15 In addition, microsurgical techniques necessitated the development of microneurosurgical instrumentation. With the instrumentation and mechanics of microneurosurgery developed, the marriage of the surgical microscope and image guided techniques will surely introduce the opportunities in the new millennium.
Angiography In the early 1900s, ligature of the carotid artery in the neck was advocated as a possible successful treatment mode for intracranial aneurysm.16 During the 1940s, however, experimentation was done by percutaneous carotid angiography (which led to accidental vertebral angiography), percutaneous deliberate vertebral angiography, and retrograde brachial vertebral angiography.17 By 1950, cerebral angiography was the accepted diagnostic tool to visualize aneurysms.
During subsequent decades, cerebral angiography and digital subtraction angiography enabled the neurosurgeon to analyze the angiographic details of intracranial aneurysms including site, size, shape and number of aneurysms, as well as the configuration and condition of the collateral Circle of Willis. Various surgical approaches and a range of aneurysm clips were introduced including several types that could be adjusted or removed after initial placement.18
Accelerating technical and scientific advances during the latter part of this century gave way to the introduction of diagnostic tools, such as CT, MRI, SPECT, PET, DSA, 3-dimensional CT angiography, and superselective catheterization for cerebral angiography, as well as endovascular occlusion of the aneurysm with balloon or electrocoil techniques and aneurysmal microsurgical illumination.19
Building for the Future
Unquestionably, there was much more to the advancement of neurosurgery during the 20th century than the imaging processes documented. But, without the diagnostic capabilities provided through pre-, intra-, and post-surgical imaging, would the myriad of procedures that we see today have developed? Spinal instrumentation, pain management, angioplasty, trauma management – the improvements in these arenas were a result of new imaging techniques and advances in anesthesia, hemostasis, and pharmaceuticals.
Drs. Dandy and Cushing may have worked at a different level of thought than other surgeons of their time, but their abilities to support interdisciplinary projects under their direction influenced subsequent generations of neurosurgeons to embrace the new modalities developed in collaboration with their non-neurosurgical colleagues. The end result has been the highest level of neurosurgical care ever to exist, and the assurance that the progress will continue in the future.