Dandy is credited with numerous neurosurgical discoveries and innovations, including the description of the circulation of cerebrospinal fluid in the brain, surgical treatment of hydrocephalus, the invention of air ventriculography and pneumoencephalography, the description of brain endoscopy, the establishment of the first intensive care unit (Fox 1984, p. 82), and the first clipping of an intracranial aneurysm, which marked the birth of cerebrovascular neurosurgery.

In 1911, he earned a Master of Arts degree for his work in the Hunterian Laboratory, and went on to join the Johns Hopkins Hospital surgical housestaff for one year as Cushing's Assistant Resident (1911–1912).

Dandy joined the staff of the Johns Hopkins Hospital in 1918 and immediately focused his energies on the surgical treatment of disorders of the brain and spinal cord.

Dandy's first scientific contribution was the detailed anatomical description of a 2 mm human embryo in Franklin P. Mall's collection.

In 1913 and 1914, Dandy and Kenneth D. Blackfan published two landmark papers on the production, circulation, and absorption of CSF in the brain and on the causes and potential treatments of hydrocephalus.

In 1944 A. Earl Walker (who eventually became chairman of neurosurgery at Johns Hopkins) described a similar case of congenital closure of the outflow of the fourth ventricle.

As a general surgeon, Dandy was aware of the ability of free air in the peritoneal cavity to outline the abdominal contents.

(Fox 1984, p. 43) Gilbert Horrax stated: "The importance of this diagnostic method, ... for the more accurate localization of many growths whose situation could not be ascertained with absolute exactness, can hardly be overemphasized.

It brought immediately into the operable field at least one third more brain tumors than could be diagnosed and localized previously by the most refined neurological methods."

(Fox 1984, p.45)Air ventriculography, however, had the limitation that a burr hole had to be drilled in the skull to pass the needle into the ventricular system.

Already by 1919, barely one year after finishing his surgical training, Dandy was recognized arguably as the premier surgeon at Johns Hopkins.

He has the devotion and confidence of all his associates and treats them in a really beautiful way ..." (Fox 1984, p.54)Dandy's surgical innovations proceeded at an astounding rate as he became increasingly comfortable operating on the brain and spinal cord.

Dandy's 1938 description of surgery for clipping of an intracranial aneurysm is particularly important because it marked the birth of the subspecialty of cerebrovascular neurosurgery.

In 1944, two years prior to his death, Dandy published a book entitled Intracranial Arterial Aneurysms in which he summarized his experience with these treacherous and technically formidable lesions.

Dandy established at the Johns Hopkins Hospital a clinical service that served the dual purpose of delivering outstanding care to his patients and also of training surgical residents and fellows to become neurosurgeons.

(Sherman et al. 2006) In 1923, five years after finishing his arduous surgical training, Dandy started to focus on his personal life.

There were other stories, also true, of Dandy having outbursts of temper when "things did not go right in the operating room," firing assistant residents, scolding personnel, and occasionally throwing an instrument.

... although Dandy was at times dictatorial and demanding, his actions made it obvious that he cared deeply for our welfare, although not about how hard we worked."

His personality is best summarized in his obituary in the Baltimore Sun of April 20, 1946:"... Gruff of manner, hot of temper, and endowed with a tongue as sharp as his instruments, he exacted awe, respect, and the hardest kind of work from his students.

Dandy enjoyed excellent health most of his life, except for November and December 1919, the year after completing his residency, when he became bedridden with sciatic neuralgia.

The society is a forum for surgeons around the world to enhance the education of both neurosurgery residents and fully trained neurosurgeons to take part in the development and distribution of guidelines for clinical decision making utilizing the best available science.