engleski

Cerebrospinal fluid pressure gradients and pathophysiology of hydrocephalus

INTRODUCTION: Factors which determine cerebrospinal fluid (CSF) volume and pressure (CSFP) inside the craniospinal system in healthy subjects and in patients with CSF pathway stenosis/obstruction aren't well defined. It is generally believed that CSF volume and pressure are regulated by rate of CSF secretion as well as resistance to CSF circulation and absorption. We hypothesized that CSF volume and pressure changes depend on biophysical characteristics of cranial and spinal intradural spaces and laws of fluid mecahnics. METHODS: Mentioned hypothesis was tested on cats and artificial model of cranio-spinal space. CSFP changes in cats under different experimental conditions (increase/decrease of spinal CSF volume ; with/without cervical stenosis ; various postures) were compared with those in artificial model consisting of non-distensible „cranial“ and distensible „spinal“ part. RESULTS: CSFP inside the cranium and lumbar region of cats with normal cranio-spinal communication was almost the same as in „cranial“ and „lumbar“ model regions in tested postures. Negative intracranial pressure was stable during recording in animals and model with nornal communication in upright position, while in animals with cervical stenosis the intracranial CSFP was positive. Intraspinal CSF volume changes significantly alter intracranial CSF pressure in all tested conditions. CONCLUSIONS: It seems that CSFP in the cranio- spinal space is determined by laws of fluid mechanics, and does not depend on the CSF secretion, unidirectional circulation and absorption. CSFP gradients under certain experimental circumstances biophysically enable development of hydrocephalus. Observed results suggest that hydrocephalus is a consequence of impaired hydrodynamics of intracranial fluids between CSF, brain and blood compartments.

cerebrospinal fluid ; cerebrospinal fluid pressure ; body position changes ; cats ; artificial model of cranio-spinal space

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