Elevated Intracranial Pressure Impairs Cerebrospinal Fluid Drainage to Meningeal Lymphatic Vessels*

Cerebrospinal fluid (CSF) has recently gained increasing recognition for its role in clearing metabolic wastes from the brain. Over the past decade, experiments have revealed the presence of meningeal lymphatic vessels (mLVs) in the tissues surrounding the brain (meninges), which play a crucial role in absorbing and draining CSF from the subarachnoid space (SAS). Counterintuitively, recent experiments demonstrate that elevated intracranial pressure (ICP) in the SAS leads to a reduction in downstream flow through the mLVs. Our research aims to model CSF efflux through mLVs using numerical analysis. We use ICP as an inlet pressure for the mLVs model. We derive an expression that relates ICP and its effect on the meninges using solid mechanics equations. Then, we use the 1D Navier-Stokes equation, coupled with an algebraic equation derived from the structural analysis of the meninges, to simulate fluid flow through the mLVs. Our preliminary results demonstrate that elevated ICP leads to reduced CSF drainage through mLVs due to decreased vessel diameter and impaired intrinsic pumping. This finding provides a novel explanation for why elevated ICP disrupts CSF circulation and drainage, as observed in hydrocephalus, traumatic brain injury, and much more.