Authors: Jordan L. Davies, MD
Over 50% of cerebral spinal fluid shunts fail due to proximal catheter obstruction from tissue or cells. Treatment modalities to modify catheter cell adhesion properties are susceptible to foreign body reactions, that trigger immune cascade via astrocyte activation. This can then cause catheter occlusion. This study aims to understand this mechanism of catheter occlusion, utilizing an in vitro physiologic model of the cytopathological changes that contribute to catheter occlusion.Methods: A double chamber, 3D printed, in vitro system was fabricated to test commercial-available shunt catheters. The upper chamber contains biogel and cultured human astrocytes. The lower chamber contains artificial or human cerebral spinal fluid. A catheter is inserted through upper chamber into lower chamber until the catheter holes are fully immersed within the lower chamber. A micro pump connected to the distal end of the catheter pumps 0.5 mL per minute through the closed circuit. The system is contained in a pressure chamber where pressure can be controlled via an air pump.
We have successfully created a model of astrocyte mediated, shunt catheter obstruction utilizing an in vitro system. The physiologic properties are regulated to mimic human cerebral spinal fluid circulation and intracranial pressure. This data are significant in the understanding of modalities that will be utilized to prevent shunt catheter occlusion.
To our knowledge, this is the first in vitro system to mimic the cytopathology of an astrocyte induced catheter obstruction. It can be a fundamental tool to understand the process of this mechanism of catheter occlusion and provide a framework to test future catheters.