Third ventriculostomy: history, anatomical bases, techniques and experience of the author

THESES

THIRD VENTRICULOSTOMY: HISTORY, ANATOMICAL BASES, TECHNIQUES AND EXPERIENCE OF THE AUTHOR (ABSTRACT)^*. THESIS. SÃO PAULO, 1997.

SAMUEL CAPUTO DE CASTRO^**

The knowledge about hydrocephalus and its management has been slow and gradual since the early times of Medicine until the present state of the art. Robert Whytt (1714-1766) provided the first description of the clinical picture of the disease and the consequences of the increased intracranial pressure. Morgani (1682-1771) provided a detailed description of pathology. The most important contribution in our century had been afforded by Walter Dandy (1886-1946) as such: 1) he defined hydrocephalus as a ventriculomegaly where there is a gradient of pressure between the ventricular cerebral spinal fluid (CSF) and the brain parenchyma; 2) he classified it as obstructive and communicant according the place where occurred the mechanical obstruction; 3) he established the basis for its control stating that to treat obstructive hydrocephalus one must to perform a thirdventriculostomy and to treat the communicant one to perform an extirpation of the choroid plexus.

According to these principles several surgical techniques of ventriculostomy were developed since the decade of 1920. Some had made landmark. The first of them had been the own technique of Dandy (1922) by which, throughout a subfrontal craniotomy and sacrifice of a sound optic nerve, the floor of the third ventricle is opened toward the base cistern. The one of Mixter (1923) throughout a percutaneous coronal approach under endoscopic vision, the floor of the third ventricle is perforated, communicating it with the interpeduncular cistern. McNickle (1947) and Forjaz (1968) had done the procedure but under radiological control.

From 1947 on, with the introduction of the silastic in Medicine, the external shunts of the CSF toward the abdominal cavity or the heart took the place. Only after the decade of sixties, allowed by the invention of Harold Hopkins of the hod lens and the optic fibers (easing the manufacture of delicate instruments) the modern endoscopic thirdventriculostomy became the standard procedure for the treatment of the obstructive forms of hydrocephalus.

Two anatomic giving of the nature make possible and minimal invasive the endoscopic percutaneous approach to the base cisterns: 1) from the point of Kocher a probe (or a ventriculoscope) transverse the silent frontal cortical mantle, falls into the ventricle cavity and throughout a straight line pass the foramen of Monro to the third ventricle; 2) the floor of the third ventricle, in hydrocephalus, is a thin membrane which separate the intracerebral cavities from the cisterns, becoming easy to make a bypass to CSF.

To indicate it we base on clinical picture of the patient and on exams which show the ventriculomegaly as ultrasonography, axial computed tomography and nuclear magnetic resonance of the brain. The transcranial Doppler has been demonstrated to be a valid method to investigate about the grade of the intracranial hypertension which come together the hydrocephalus, as much pre as post operative. The resolution of the clinical symptoms of the patient, the return to normal values on the several dates of the transcranial Doppler tests and reduction of the size of ventriculomegaly are the parameters on those we base to evaluate the success. There is no reliable test presently to confirm the patence of the opening created by the ventriculostomy. Therefore, the cine bidimensional magnetic resonance recently accessible can soon fulfill this gap.

We presented our experience in 23 patients which undergone this procedure. At the lactant group we had success to control the symptoms of hydrocephalus in 3 out of the 8 carriers of aqueduct stenosis and in 2 out of 4 hydrocephalus associated to myelomeningocele. At children and adults we had success in 5 out of 6, being 4 carriers of aqueduct stenosis, one of a pineal tumor and one of a cyst of the quadrigeminal plate. We had one death: an adult patient at the beginning of the series. On the 5 carriers of hydrocephalus following ventriculitis, meningitis or brain hemorrhage we do not had any success.

At literature, this method presents morbidity rate bellow 5% and mortality rate less than 1%. It applied to lactants offer 40% of cure and to adults 80%, allowing them to be free of the chronic dependence of the shunts. To these results none technique developed until now equals for the treatment of the obstructive hydrocephalus.

KEY WORDS: non-communicating hydrocephalus, treatment, third ventriculostomy.

**Address: Rua Artur Bernardes 433, 38400-368 Uberlândia MG, Brasil.

*

Terceiro ventriculostomia: histórico, bases anatômicas, técnicas e experiência do autor (Resumo). Tese de Mestrado, Faculdade de Medicina da Universidade Federal de São Paulo (Área: Neurocirurgia). Orientador: Sérgio Cavalheiro. Estudo realizado com bolsa da CAPES.

Publication Dates

• Publication in this collection
  06 Dec 2000
• Date of issue
  Sept 1998