A236 Subarachnoid trabeculae and CSF flow: potential role in the development of communicating hydrocephalus

<h3>Introduction</h3> Cerebrospinal fluid (CSF) dynamics within the subarachnoid space are critically influenced by the fine morphology of the arachnoid trabeculae, yet their contribution to CSF flow regulation remains poorly understood. <h3>Aim of Study</h3> To investigate how changes in subarachnoid space porosity affect CSF flow, using a real-time anatomical model derived from in-vivo high-frequency optical coherence tomography (HF-OCT) data. <h3>Method</h3> A canine model was used to acquire in-vivo HF-OCT imaging of the subarachnoid space (SAS) microarchitecture, particularly around major blood vessels of the posterior circulation. Imaging through the vessel wall along the vertebrobasilar axis enabled detailed visualization of the trabecular network. From this data, a 3D true anatomical model of the SAS and its trabeculae was reconstructed. Variations in trabecular thickness were applied selectively within the model. High-resolution computational fluid dynamics (CFD) simulations were then used to assess the resulting changes in CSF pressure drop. <h3>Results</h3> A localized 5% increase in trabecular thickness of membranes distal to the artery resulted in a fivefold increase in pressure drop across the control volume. In contrast, a uniform 5% increase across the entire segment produced only marginal additional changes. The average initial thickness of the trabecular fibers was approximately 50 microns.These findings indicate that specific trabecular structures disproportionately affect CSF flow resistance. Smaller changes in trabecular thickness produced measurable changes in pressure drop but were not found to be significant. <h3>Conclusion</h3> Our findings suggest that the arachnoid trabeculae play a critical role in modulating CSF dynamics. Alterations in their microstructure may contribute to the pathophysiology of communicating hydrocephalus. <h3>Conflict of Interest</h3> No