Communicating hydrocephalus induced by mechanically increased amplitude of the intraventricular cerebrospinal fluid pressure: Experimental studies

Development of hydrocephalus and classical hypothesis of cerebrospinal fluid hydrodynamics: Facts and illusions

“…This consideration is supported by the observations that in patients with communicative and non-communicative hydrocephalus, transmantle pressure is absent (Stephensen et al, 2002). All of the evidence supports the idea that the transmantle pressure gradient may not be necessary or instrumental for the development of hydrocephalus, and that some other factors such as an increase in the ventricular CSF pulse pressure without affecting the CSF pressure (Di Rocco et al, 1978), an impairment of systolic-diastolic displacement of the CSF with the development of periventricular ischemia (Miše et al 1996), changes in the arterial pulsations (Greitz, 2004 and, an increase in ventricular CSF osmolarity without affecting the CSF pressure (Krishnamuthy et al, 2009), and venous compliance (Bateman, 2000 and2003) may play an important role in the development of that pathological process (see Section 8. -Mechanisms of hydrocephalus development which are not in accordance with the classical hypothesis of CSF hydrodynamics).…”

“…The best clinical evidence of a secondary aqueductal stenosis was given by Foltz and Shurtleff (1966), who found that among 27 patients with communicating hydrocephalus, 12 developed secondary aqueductal stenosis or aqueductal occlusion during chronic venticulo-atrial shunting. Furthermore, in lambs, acute and chronic hydrocephalus was induced without interfering with the CSF circulation or absorption (Di Rocco et al, 1978) by mechanically increasing the amplitude of the CSF intraventricular pulse pressure without modifying the mean CSF pressure. On newborn hamsters and cats, after an intracerebral infection with a virus vaccine, hydrocephalus has been developed without the stenosis of the aqueduct or fibrosis of the subarachnoid space (Davis, 1981).…”

“…Namely, hydrocephalus was induced in lambs by increasing the amplitude of the CSF intraventricular pressure mechanically (Di Rocco et al, 1978), without modifying the mean CSF pressure and without interfering with CSF circulation or CSF absorption. The fact that the CSF system was completely passable and that CSF absorption was not insufficient, clearly indicates that the high-amplitude intraventricular CSF pulsation is the genesis of ventricular enlargement.…”

Pathogenesis of Leukoaraiosis

“…In fact, while thè mean CSF pressure may be normal, thè pulse pressure can be markedly increased in normal pressure hydrocephalus. 84 The hypothesis that increased ventricular pressure causes ischemie changes in thè WM is supported by observations showing that among patients with normal pressure hydrocephalus, blood flow in thè WM returns to normal values after shunting procedures that lower thè intraventricular pressure; this is accompanicd by parallel clinical improvement and reduction in thè severity of LA.85 (2) The second mechanism could involve alterations in thè ependymal lining. Leakage of CSF into thè adjacent brain parenchyma may be thè result of structural alterations in thè ependymal cells.…”

The formation of cerebrospinal fluid: Nearly a hundred years of interpretations and misinterpretations

“…For example, some other factors, such as an increase in the ventricular CSF pulse pressure (Di Rocco et al, 1978), an impairment of systolic-diastolic displacement of the CSF with the development of periventricular ischemia (Miše et al, 1996), cardiac disease (Luciano and Dombrowski, 2007), changes in arterial pulsations (Greitz, 2004 and and venous compliance (Bateman, 2000 and2003) may play an important role in the development of that pathological process.…”