Walter Dandy

Walter Edward Dandy (April 6, 1886-April 19, 1946) was an American neurosurgeon. He is considered as one of the founding fathers of modern neurosurgery.

After graduation Dandy became the sixth appointee to the Hunterian Laboratory of Experimental Medicine under Harvey W. Cushing from 1910-1911. 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 house staff for one year as Cushing's Assistant Resident (1911-1912). Dandy completed his general surgery residency at the Johns Hopkins Hospital under William S. Halsted in 1918. While Dandy was introduced to the nascent field of neurosurgery by Cushing, it was George J. Heuer who completed Dandy's neurosurgical training after Cushing's departure for the Peter Bent Brigham Hospital in Boston in September 1912. Heuer had graduated from the Johns Hopkins University School of Medicine , worked as Cushing's first Assistant Resident  and served as Halsted's Chief Resident.

One of the earliest products of the Hunterian experience was Walter Dandy. During the two years after medical school, Dandy completed his monumental work on cerebrospinal fluid production, judged by many to be the finest piece of surgical research ever accomplished. While still a house officer, he devised pneumo-encephalography, which was the basis of neurological imaging for nearly 50 years. Dandy went on the be the most famous surgeon of his generation and the greatest technician the field has known. His innovations introduced surgery for disc disease, surgery for aneurysms and arteriovenous malformations as well as surgery for functional disease. The modern scope of neurosurgery was encompassed by Dandy.

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. When Heuer left Hopkins in 1922 to become the head of surgery at the University of Cinicinnati, Dandy remained as the only neurosurgeon at the Johns Hopkins Hospital until his death in that hospital in 1946.

Dandy is credited with numerous neurosurgical discoveries and innovations, including the description of the circulation of CSF in the brain, surgical treatment of hydrocephalus, the innovation of air ventriculography & pneumoencephalography, the description of brain endoscopy, the establishment of first intensive care unit and first clipping of an intracranial aneurysm.

Walter Dandy trained under Cushing at John Hopkins Hospital. Dandy made a number important contributions to neurosurgery. Dandy developed the technique of pneumoencephalography and provided the neurosurgeon the opportunity to localize a brain tumor by analyzing the displacement of air in the ventricles.

Dandy was an innovative neurosurgeon, considerably more aggressive in style and technique than Cushing.

Dandy was first to show that acoustic neuroma could be removed in totality.

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. Hydrocephalus is the buildup of CSF within the brain, an often lethal condition if left untreated. They described two forms of hydrocephalus, namely "obstructive" and "communicating," thus establishing a theoretical framework for the rational treatment of this condition.

He first introduced the technique ablating and removing the choroid plexus to reduce the production of CSF  for treating hydrocephalus.

In 1921 Dandy reported a case of hydrocephalus caused by obstruction of outflow of CSF from the fourth ventricle. 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. This congenital anomaly became known as the Dandy-Walker cyst. It is associated with closure of the foramina of Luschka and Magendie (the outflow openings of the fourth ventricle), atrophy of the cerebellum and cerebellar vermis, dilation of the fourth ventricle, hydrocephalus, and often atrophy of the corpus callosum.

Dandy was among the first to surgically deal with cerebral aneurysms by obliterating them with snare ligatures or metal clips.

Dandy's surgical innovations proceeded at an astounding rate as he became increasingly comfortable operating on the brain and spinal cord. He described in 1921 an operation for the removal of tumors of the pineal region, in 1922 complete removal of tumors of the cerebellopontine angle (namely acoustic neuromas), in 1922 the use of endoscopy for the treatment of hydrocephalus ("cerebral ventriculoscopy"), in 1925 sectioning the trigeminal nerve at the brainstem to treat trigeminal neuralgia, in 1928 treatment of Ménière's disease (recurrent vertiginous dizziness) by sectioning the vestibular nerves, in 1929 removal of a herniated disc in the spine, in 1930 treatment of spasmodic torticollis, in 1933 removal of the entire cerebral hemisphere ("hemispherectomy") for the treatment of malignant tumors, in 1933 removal of deep tumors within the ventricular system, in 1935 treatment of carotid-cavernous fistulas (CCFs), in 1938 ligation or "clipping" of an intracranial aneurysm, and in 1941 removal of orbital tumors.

Walter Dandy’s many contributions have earned him a prominent place in the annals of neurological surgery.

Sources:

Wikipedia

http://www.hopkinsmedicine.org/neurology_neurosurgery

The society of Neurological Surgeons

Youmans Neurological Surgery ( H. Richard Winn)

Harvey Williams Cushing

Harvey Williams Cushing (April 8, 1869 – October 7, 1939)  is often called the "father of modern neurosurgery." He was the founder of American neurosurgery.

He studied medicine at Harvard Medical School at received degree in 1895. He did residency in surgery under the guidance of  famous surgeon , William  Halsted at John Hopkins Hospital, Baltimore. Cushing learned meticulous surgical technique from his mentor. As was standard then, Cushing spent time in Europe ; he worked in the laboratories of Theodore Kocher in Bern, where he investigated the physiology of CSF. He described Cushing reflex, relationship between blood pressure and intracranial pressure.

While traveling through Europe , he met several important surgical personalities , including Victor Horsley.  

The specialty of neurosurgery was born at Johns Hopkins. In 1900, Harvey Cushing completed his surgical training. After the European grand tour and a year in Kocher's laboratory in Bern where he studied the effects of head injury, Cushing returned to the surgical faculty. In the ensuing 12 years, he founded the specialty of neurosurgery and established the characteristics of the field which endure to this day.
By the time Cushing accepted the Harvard Chair of surgery in 1912, his work at Johns Hopkins had established him as the outstanding young surgeon in the United States. Cushing brought Halsted's meticulous surgical technique to the new field and added Osler's careful clinical observation and his own penchant for accurate documentation. His clinical contributions are legendary: the use of x-rays in surgical practice, physiological saline for irrigation during surgery, understanding the pituitary's function, founding the clinical specialty of endocrinology, the anesthesia record, the use of blood pressure measurement in surgical practice, and the physiological consequences of increased intracranial pressure.

One of the principal inducements for Cushing to stay in Baltimore upon completion of his residency was his appointment as Director of the Hunterian Laboratory. Our concept of the clinician/scientist in medicine largely derives from Cushing's vision of the Hunterian as a place for young physicians to learn to do research.One of the earliest products of the Hunterian experience was Walter Dandy.

He described endocrine syndrome due to basophilic adenoma of pituitary gland ( Cushing disease).

With Percival Bailey in 1926, Cushing introduced the first rational approach to the classification of brain tumors.

At age of 32 , he became associate professor of surgery at John Hopkins Hospital and was in full charge of cases of surgery of the central nervous system.

He made (with Kocher) a study of ICP and (with Sherrington) contributed much to the localization of the cerebral centers.

In 1911, he was appointed surgeon-in-chief at Peter Bent Brigham Hospital in Boston. He became a professor of surgery at the Harvard Medical School starting in 1912. From 1933 to 1937, when he retired, he worked at Yale University School of Medicine.

In the beginning of the 20th century he developed many of the basic surgical techniques for operating on the brain. This established him as one of the foremost leaders and experts in the field. Under his influence neurosurgery became a new and autonomous surgical discipline.

He considerably improved the survival of patients after difficult brain operations for intracranial tumors. He used x-rays to diagnose brain tumors. He used electrical stimuli for study of the human sensory cortex. He had operated more than 2000 cases brain tumors.

Cushing was also awarded the Pulitzer Prize of biography in 1926 for a book recounting the life of one of the fathers of modern medicine, Sir William Osler.

He developed many surgical instruments that are still in use today, most notably the Cushing forceps, He also developed a surgical magnet while working with the Harvard Medical Unit in France during World War I to extract bullets from the heads of wounded soldiers.

Sources: Wikipedia
               Y. Neurological surgery  ( H.R. Winn ) Elsevier Saunders
              http://www.hopkinsmedicine.org/neurology_neurosurgery

Sir Victor Horsley: Pioneer of neurological surgery

 

 

Sir Victor Horsley was the first physician to remove a spinal tumor, in 1887, by means of a laminectomy. He developed many practical neurosurgical techniques, including the hemostatic bone wax, the skin flap, the ligation of the carotid artery to treat cerebral aneurysms, the transcranial approach to the pituitary gland and the intradural division of the trigeminal nerve root for the surgical treatment of trigeminal neuralgia.

As a neuroscientist, he carried out studies of the functions of the brain in animals and humans, particularly on the cerebral cortex. His studies on motor response to faradic electrical stimulation of the cerebral cortex, internal capsule and spinal cord became classics of the field. These studies were later translated to his pioneering work in the neurosurgery for epilepsy. Horsley was also the first to use intraoperative electrical stimulation of the cortex for the localization of epileptic foci in humans, between 1884 and 1886.

His best known innovation is the Horsley–Clarke apparatus (developed together with Robert H. Clarke in 1908) for performing the so-called stereotactic neurosurgery, whereby a set of precise numerical coordinates are used to locate each brain structure.

Source: Wikipedia 

Immortalized in surgical history for the introduction of "antiseptic wax," Sir Victor Horsley played a pivotal role in shaping the face of standard neurosurgical practice. His contributions include the first laminectomy for spinal neoplasm, the first carotid ligation for cerebral aneurysm, the curved skin flap, the transcranial approach to the pituitary gland, intradural division of the trigeminal nerve root for trigeminal neuralgia, and surface marking of the cerebral cortex. A tireless scientist, he was a significant player in discovering the cure for myxedema, the eradication of rabies from England, and the invention of the Horsley-Clarke stereotactic frame. As a pathologist, Horsley performed research on bacteria and edema and founded the Journal of Pathology. Horsley's kindness, humility, and generous spirit endeared him to patients, colleagues, and students. Born to privilege, he was nonetheless dedicated to improving the lot of the common man and directed his efforts toward the suffrage of women, medical reform, and free health care for the working class. Knighted in 1902 for his many contributions to medicine, Sir Victor met an untimely death during World War I from heat stroke at the age of 59. An iconoclast of keen intellect, unlimited energy, and consummate skill, his life and work justify his epitaph as a "pioneer of neurological surgery."

Reference: Tan TC, Black PM. Sir Victor Horsley (1857-1916): pioneer of neurological surgery .Neurosurgery. 2002 Mar;50(3):607-11; discussion 611-2.

 

 

CNS complications in HIV infection (AIDS)

Neurologic complications occur in more than 40% of patients with HIV infection. They are the presenting features of AIDS in 10-20% of cases.¹

The access to the AIDS treatment has improved leading to decreased mortality in last decade but the spread of infection is still high.

Types of CNS complications 

Brain may be affected by a variety of abnormalities in association with HIV infection. . Opportunistic infections depend upon the clinical stage of the disease, viral load and CD4⁺ Lymphocyte count.

AIDS patients are more prone for vasculitis causing stroke leading to Transient Ischemic Attack ( TIA) , infarct and hemorrhages in brain and  vascular myelopathy.

HIV- associated neurocognitive disorder

HIV encephalitis also called AIDS- dementia complex ( ADC ) , is a progressive subcortical dementia.

CNS Lymphoma

Progressive Multifocal Leukoencephalopathy ( PML)

Fungal Infections ( e.g. Cryptococcal meningitis)

Tubercular meningitis,  Toxoplasmosis, Neurocysticercosis, Cytomegalovirus ( CMV) encephalitis

Kaposi Sarcoma , Peripheral neuropathies

DIAGNOSIS

To diagnose CNS involvement in AIDS , CT scan or MRI with contrast with MR spectroscopy is very useful tool . Other investigations like CSF study and stereotactic biopsy are needed depending upon the type of involvement.

Sources:
Medscape http://www.emedicineheath.com

http://www.who.int/topics/hiv_aids

http://www.nhs.uk/conditions/hiv

http://www.theglobalfund.org

http://www.dirjournal.org/pdf ( Diag Interv Radiol 2010; 16:193-200)

http://www.oici.org

RED

http://en.wikipedia.org/wiki/HIV/AIDS

http://aidsinfo.nih.gov

Google search

CNS Infections

Brain abscess
Pyogenic brain abscess is a focal collection of pus within the brain. It is initiated when bacteria gain entry into cerebral tissues with trauma, contiguous spread from a suppurative focus (in middle ear, oropharynx, & paranasal sinuses), or hematogenous dissemination from a distant infection.

Subdural empyema
pus collection in subural space. The pathogenesis of subdural empyema is similar to brain abscess.

Epidural Abscess

Osteomyelitis ( Post operative, Post Traumatic, Tubercular, Pyogenic , etc.)

Post craniotomy infections

Meningitis
      Bacterial, Viral, Fungal, Tubercular

Vertebral osteomyelitis

Spinal epidural abscess

Granulomas ( Neurocysticercosis, tubercular)

Toxoplasmosis, HIV infection ( AIDS)

Blastomycosis

Histoplasmosis

Coccidiomycosis

Paracoccidiomycosis

Cryptococcosis

Sporotrichosis

Aspergillosis

Chromoblastomycosis



 

Challenges for Neurosurgical Trainees

Neurosurgery is a new subspeciality of surgery with a very little progress in terms of clinical outcome despite of lot of technological advancements in last few decades. Neurosurgical management  has greatly been helped by advancements in neuroradiology like CT scan, MRI, and angiography. Very little progress has been witnessed over the innovative surgical skills and clinical outcome as reported during the period of Victor Horsley, Harvey Cushing and Walter Dandy about a century ago. As a trainee there is a need to have a bird eye view of the whole gamut of neurosurgery including Gamma knife, functional neurosurgery, neuro intervention, apart from learning skills of skull base neurosurgery, vascular neurosurgery , spinal instrumentation, repair of nerve injuries, surgery for craniosynostosis, spinal dysraphism, encephaloceles and neuroendoscopy. Some neurosurgical centers  may not have expertise and facilities for providing comprehensive teaching and training in neurosurgery.