engleski

New concepts of cerebrospinal fluid (CSF) physiology and hydrocephalus development

Objective It is generally believed that cerebrospinal fluid (CSF) formation is an active energy consuming metabolic process which occurs mainly through choroid plexuses inside brain ventricles. CSF formation, absorption and circulation represent the so-called classic hypothesis of CSF hydrodynamics. However, that classic hypothesis of CSF physiology and traditional concept of hydrocephalus are contradicted with numerous experimental and clinical data, which consequently results with unsatisfying clinical treatment and patient recovery. Thus, in this presentation a new hypothesis of CSF physiology and a new concept of hydrocephalus development in light of this hypothesis have been analyzed and discussed. Methods New hypothesis of CSF physiology was created after more than four decades of experimental work on anaesthetized and free moving rats, rabbits, cats and dogs, and after collecting various data from patients and literature. During that period, several new experimental models have been introduced (for example: acute and subchronic blockade of aqueductus of Sylvii, acute and chronic stenosis of cervical subarachnoid space, ventriculo-aqueductal perfusion) by our research team. Neuroradiological methods are inevitable in diagnostic workup of patients with CSF disturbances. These methods are also excellent experimental tools for visualization of CSF dynamics and volume changes in physiological and pathological conditions. Results Acute occlusion of aqueduct of Sylvius does not change CSF pressure in isolated ventricles of experimental animals, which is in opposition to generally accepted mechanisms of hydrocephalus development. Furthermore, our clinical cases of patients with long lasting obstruction of aqueduct of Sylvius, but without development of hydrocephalus, also confront classical concept of CSF physiology. Substances with long residence time inside CSF showed multidirectional distribution which is caused by to-and-fro pulsations of these fluids and their mixing. This suggests that there is no unidirectional CSF circulation, as proposed by classical concept. On the contrary, after application of these substances into the CSF system (in both animals and patients), their distribution is often opposite of the direction proposed by classical hypothesis. Conclusion New hypothesis suggests that CSF volume (99% water) is regulated via brain tissue microvessels, following the gradient of hydrostatic and osmotic forces. All of the results obtained from patients and experimental animals suggest that hydrocephalus is a pathological state in which CSF is excessively accumulated inside the cranial part of the CSF system, predominantly in one or more brain ventricles, as a consequence of impaired hydrodynamics of intracranial fluids between CSF, brain and blood compartments.

hydrocephalus ; cerebrospinal fluid

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