A computational fluid dynamics simulation framework for ventricular catheter design optimization

Weisenberg, Sofy H.; TerMaath, Stephanie C.; Barbier, Charlotte; Hill, Judith; Killeffer, James A.

doi:10.3171/2017.5.jns161882

Cited by 5 publications

(2 citation statements)

References 27 publications

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“…In support of their hypothesis, the authors state that obstructing tissue is found most frequently around the most downstream set of holes in explanted catheters, yet clear evidence for this claim is currently lacking. However, based on this hypothesis, multiple studies have attempted to homogenize the flow rate distribution across catheter holes by changing the catheter hole geometry [29,37,47] in an effort to decrease the probability of aspirating bulk tissue and cells at a given hole. By contrast, based on the response of astrocytes to long-term shear flow, we set the design objective for ventricular catheters to maximizing wall shear stress across the inner surfaces of a catheter.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, we considered a case where the cerebral ventricles are so enlarged that frictional loss from the ventricular wall is negligible. We ensured this condition in the simulation by enclosing the ventricular catheter into a box domain whose walls are sufficiently distant from the catheter (figure 8), which also meets the distance condition suggested by Weisenberg et al [29]. We imposed a constant normal velocity condition on the surface of the domain that faces the tip of the catheter and zero-pressure condition on the outlet of the catheter.…”

Section: Formation Of Low Wall Shear Stress Zone In Typical Ventricular Cathetermentioning

confidence: 98%

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Enhanced wall shear stress prevents obstruction by astrocytes in ventricular catheters

Lee¹,

Kwok

Holsapple

et al. 2020

J. R. Soc. Interface.

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The treatment of hydrocephalus often involves the placement of a shunt catheter into the cerebrospinal ventricular space, though such ventricular catheters often fail by tissue obstruction. While diverse cell types contribute to the obstruction, astrocytes are believed to contribute to late catheter failure that can occur months after shunt insertion. Using in vitro microfluidic cultures of astrocytes, we show that applied fluid shear stress leads to a decrease of cell confluency and the loss of their typical stellate cell morphology. Furthermore, we show that astrocytes exposed to moderate shear stress for an extended period of time are detached more easily upon suddenly imposed high fluid shear stress. In light of these findings and examining the range of values of wall shear stress in a typical ventricular catheter through computational fluid dynamics (CFD) simulation, we find that the typical geometry of ventricular catheters has low wall shear stress zones that can favour the growth and adhesion of astrocytes, thus promoting obstruction. Using high-precision direct flow visualization and CFD simulations, we discover that the catheter flow can be formulated as a network of Poiseuille flows. Based on this observation, we leverage a Poiseuille network model to optimize ventricular catheter design such that the distribution of wall shear stress is above a critical threshold to minimize astrocyte adhesion and growth. Using this approach, we also suggest a novel design principle that not only optimizes the wall shear stress distribution but also eliminates a stagnation zone with low wall shear stress, which is common to current ventricular catheters.

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Section: Discussionmentioning

confidence: 99%

Section: Formation Of Low Wall Shear Stress Zone In Typical Ventricular Cathetermentioning

confidence: 98%