Investigation of Spaceflight Associated Neuro-Ocular Syndrome Asymmetry through Asymmetric Cranial Venous Modeling

Date

7/12/2021

Journal Title

Journal ISSN

Volume Title

Publisher

50th International Conference on Environmental Systems

Abstract

The Spaceflight Associated Neuro-ocular Syndrome (SANS) often presents with asymmetrical ocular structural changes, including asymmetric optic disc edema. The pathophysiology of these asymmetric SANS findings is unknown. Asymmetric pressure changes within the perioptic subarachnoid space are theorized to cause these findings. Asymmetric venous sinuses near the orbits could potentially result in asymmetric pressure changes within the perioptic subarachnoid space. MRI studies of normal subjects show a dominance of venous flow through the right transverse sinus in 59% of cases and hypoplasia of the left sinus in 39% of cases, suggesting that the right transverse sinus is dominant in approximately 60% of the population. In this paper we present research to increase the fidelity of a computational craniovascular model to investigate the role of cranial venous pathway asymmetry in SANS findings. The computational craniovascular lumped-parameter model was previously developed by Creare, LLC in collaboration with the Geisel School of Medicine at Dartmouth College. The model predicts changes to the structure and function of the cranial venous system in response to hydrostatic gradients, fluid shifts, and tissue weight changes. The model includes a circulatory sub-model, a CSF sub-model, and an aqueous humor sub-model, but only includes a single venous drainage pathway. This limits its usefulness for studying asymmetric venous pathways and their effects on SANS. The model was modified to increase the number of lumped-parameter compartments in the cranial venous pathways and to model cranial venous pathways bilaterally instead of with a single pathway. Asymmetries will be introduced into the geometry of the modeled, bilateral venous sinuses to investigate their role in the development of asymmetrical ocular findings in microgravity.

Description

Michael Van Akin, University of Colorado Boulder
Jay Buckey, Geisel School of Medicine at Dartmouth College
Danielle Carroll, University of Colorado Boulder
Allison Anderson, University of Colorado Boulder
ICES513: Computational Modeling for Human Health and Performance Analysis
The 50th International Conference on Environmental Systems was held virtually on 12 July 2021 through 14 July 2021.

Keywords

spaceflight associated neuro-ocular syndrome, spaceflight physiology modeling, asymmetrical ocular findings

Citation