Computational Analysis of Cerebrospinal Fluid Flow in the Normal and Obstructed Subarachnoid Space

Patients with Chiari I malformations have increased cerebrospinal fluid (CSF) velocities compared to subjects without the malformation. Improved methods of analyzing the CSF fluid dynamics are needed to evaluate the impact of increased fluid velocities on pressure differentials in the upper cervical spinal canal and the potential impact of surgery on flow dynamics in patient-specific geometries. Here, a numerical technique based on the boundary elements method (BEM) for modeling the CSF flow within the spinal canal is presented. Results for velocity and pressure throughout the spinal canal were obtained at flow rates representative of different phases of the cardiac cycle for a healthy geometry and a Chiari model. In the healthy geometry, peak CSF velocities occurred anterolateral to the spinal cord at all flow rates. Partially obstructing the subarachnoid space increased peak systolic and diastolic velocities and shear stresses anteriorly. In addition, in the obstructed (Chiari) model, stagnation regions were evident posteriorly. The effects of surgical treatment on these CSF flow patterns warrant further study.