Biomechanická studie Syringomyelie s Chiariho malformací - mechanika míchy

Abstract

The pathogenesis of syringomyelia in association with Chiari malformation (CM) is unclear. The mechanical properties of solid tissues and cerebrospinal fluid flow have been shown to contribute to the development of syrinx. This thesis aims to study the biomechanical behavior of the spinal cord in the aforementioned diseased condition. A 2D axisymmetric poroelastic model of the spinal cord in the presence of syringomyelia was developed to understand the flow dynamics in porous solids. An arterial pressure pulse of 500 Pa was applied at the cranial end of the subarachnoid space. Transient excitation gave rise to wave propagation in the fluid-filled subarachnoid space. The main effect of the excitation was compression and swelling of spinal cord tissue at the syrinx level at different pressure conditions. The velocities of fluid entering and leaving the syrinx were relatively low i.e., in the range of 10-5 m/s such that the porous spinal cord absorbing the fluid. Stresses induced in pia mater were larger at the level of syrinx as compared to the rest of the model geometry. Although poroelasticity gives a major insight into the material interaction with fluid in a porous media, it lacks the complexities involved in free flow equations which are more realistic to determine the behavior of biological tissue. An extension to the existing model with the fluid-structure interaction module was built to study the effect of the free-flow zone connected to the poroelastic media.

The pathogenesis of syringomyelia in association with Chiari malformation (CM) is unclear. The mechanical properties of solid tissues and cerebrospinal fluid flow have been shown to contribute to the development of syrinx. This thesis aims to study the biomechanical behavior of the spinal cord in the aforementioned diseased condition. A 2D axisymmetric poroelastic model of the spinal cord in the presence of syringomyelia was developed to understand the flow dynamics in porous solids. An arterial pressure pulse of 500 Pa was applied at the cranial end of the subarachnoid space. Transient excitation gave rise to wave propagation in the fluid-filled subarachnoid space. The main effect of the excitation was compression and swelling of spinal cord tissue at the syrinx level at different pressure conditions. The velocities of fluid entering and leaving the syrinx were relatively low i.e., in the range of 10-5 m/s such that the porous spinal cord absorbing the fluid. Stresses induced in pia mater were larger at the level of syrinx as compared to the rest of the model geometry. Although poroelasticity gives a major insight into the material interaction with fluid in a porous media, it lacks the complexities involved in free flow equations which are more realistic to determine the behavior of biological tissue. An extension to the existing model with the fluid-structure interaction module was built to study the effect of the free-flow zone connected to the poroelastic media.