Dynamics of hydrocephalus: a physical approach

Abstract

As brain ventricles lose their ability to regulate the cerebrospinal fluid (CSF) pressure, serious brain conditions collectively named hydrocephalus can appear. By modelling ventricular dynamics with the laws of physics, dynamical instabilities are evidenced, caused by either CSF transport dysregulations or abnormal properties of the elasticity of the ependyma. We show that these instabilities would lead, in most cases, to dilation of the ventricles, establishing a close connection to hydrocephalus, or in some other cases to a ventricular contraction as observed in the slit ventricle syndrome. Signs seem to indicate the possibility of phase transitions occurring as a result of these instabilities, which might have important clinical consequences, such as the inability to recover a healthy state. Even so, our dynamical approach could allow the development of a unified view of these complex intracranial conditions along with a classification that might be clinically relevant.

Dual-porosity poroviscoelasticity and quantitative hydromechanical characterization of the brain tissue with experimental hydrocephalus data

“…This makes the blood and CSF flows oscillatory and thus dissimilar to the fully developed regime that Poiseuille's formulation suggests. For this reason, some recent studies on the subject undertake more realistic models such as Wormersley's flow to model the CSF flow through the aqueduct (Bouzerar et al, 2012).…”

“…This would especially be the case where the natural pathways of CSF flow are obstructed, as for instance in non-communicating hydrocephalus. Hydrocephalus is generally referred to a class of medical conditions which share the enlargement of the ventricles as a common feature (Bouzerar et al, 2012). While the interstitial fluid drains into the ventricles in normal cases, the CSF flow in the cases of hydrocephalic brain might reverse towards the parenchyma (Hochwald et al, 1969;Bloch et al, 2006), where it can be absorbed by microvessels (Sahar et al 1969a(Sahar et al , 1969b.…”

Updating technology of shunt valves

“…The physical principle underlying the use of CSF shunts is quite simple and consists in diverting the flow of CSF either to intracranial structures, jugular system, right heart atrium, pleura, peritoneum, or to other natural cavities, such as the omental bursa and the bladder [10][11][12][13][14][15][16][17] .…”

“…All systems operate by means of a differential pressure (DP) between the proximal (ventricular) and distal catheter (most commonly peritoneal) [10][11][12][13][14][15] . There are several physical factors involved in cerebrospinal fluid drainage, such as the pressure difference between the catheter tips, the patient's position, the diameter and length of the tubes, and fluid viscosity [10][11][12][13][14][15] . This relationship can be represented by the following equation:…”

“…where F is the CSF flow, DP is the variation of pressure between the ends of the catheter and R is the resistance of the system. The Hagen Poiseuille equation correlates flow resistance in a tubular system as a function of pressure, radius, length and viscosity of the fluid [10][11][12][13][14][15][16][17] :…”