Impact of Neurapheresis System on Intrathecal Cerebrospinal Fluid Dynamics: A Computational Fluid Dynamics Study

Abstract

It has been hypothesized that early and rapid filtration of blood from cerebrospinal fluid (CSF) in postsubarachnoid hemorrhage patients may reduce hospital stay and related adverse events. In this study, we formulated a subject-specific computational fluid dynamics (CFD) model to parametrically investigate the impact of a novel dual-lumen catheter-based CSF filtration system, the Neurapheresis™ system (Minnetronix Neuro, Inc., St. Paul, MN), on intrathecal CSF dynamics. The operating principle of this system is to remove CSF from one location along the spine (aspiration port), externally filter the CSF routing the retentate to a waste bag, and return permeate (uncontaminated CSF) to another location along the spine (return port). The CFD model allowed parametric simulation of how the Neurapheresis system impacts intrathecal CSF velocities and steady–steady streaming under various Neurapheresis flow settings ranging from 0.5 to 2.0 ml/min and with a constant retentate removal rate of 0.2 ml/min simulation of the Neurapheresis system were compared to a lumbar drain simulation with a typical CSF removal rate setting of 0.2 ml/min. Results showed that the Neurapheresis system at a maximum flow of 2.0 ml/min increased average steady streaming CSF velocity 2× in comparison to lumbar drain (0.190 ± 0.133 versus 0.093 ± 0.107 mm/s, respectively). This affect was localized to the region within the Neurapheresis flow loop. The mean velocities introduced by the flow loop were relatively small in comparison to normal cardiac-induced CSF velocities.

In vitro and numerical simulation of blood removal from cerebrospinal fluid: comparison of lumbar drain to Neurapheresis therapy

“…No attempt was made in this study to optimize catheter design or positioning for Neurapheresis therapy. The effect of Neurapheresis therapy on CSF steady-streaming velocities in the spinal SAS were investigated in our previous study [21]. The present study extended the previous model by including a complete CSF system, integration of a two-phase model, and developing a method for in vitro verification of results.…”

“…The dual-lumen Neurapheresis catheter geometry was identical with our previous publication [21]. In brief, the catheter was inserted at L3-L4 and located within the posterior SAS with the aspiration port at L2 and the return port at T2 vertebral level ( Fig.…”

“…The different locations of the aspiration and return ports may facilitate advective bulk movement of CSF between the ports within the SAS. Additional details on Neurapheresis therapy are provided by Khani et al [21].…”

“…This study provided information about the potential of CSF filtration to assist with blood removal under different body orientations (i.e., supine versus upright) with an idealized representation of CSF space anatomy. Khani et al [21] formulated a numerical model to investigate the impact of Neurapheresis Keywords: Computational fluid dynamics, In-vitro model, Subarachnoid hemorrhage, Neurapheresis therapy, Cerebrospinal fluid filtration, Multiphase simulation therapy on CSF flow velocities in a realistic spinal SAS geometry with subject-specific CSF flow along the spine. However, this model did not take into account the intracranial portion of the CSF system and lacked a multiphase fluid mixture of blood and CSF.…”

In vitro and Numerical Simulation of Blood Removal from Cerebrospinal Fluid: Comparison of Lumbar Drain to Neurapheresis Therapy

“…This study provided information about the potential of CSF filtration to assist with blood removal under different body orientations (i.e., supine versus upright) with an idealized representation of CSF space anatomy. Khani et al formulated a numerical model to investigate the impact of Neurapheresis therapy on CSF flow velocities in a realistic spinal SAS geometry with subject-specific CSF flow along the spine (20). However, this model did not take into account the intracranial portion of the CSF system and lacked a multiphase fluid mixture of blood and CSF.…”