Role of cerebroventricular size and surgical placement in modulating catheter flow distribution

Abstract Ventricular shunt catheters are the standard of care for managing hydrocephalus, yet 40% of implanted catheters fail within two years of implantation, mainly due to proximal catheter obstruction. Prior literature suggests that cerebrospinal fluid (CSF) preferentially enters the ventricular catheter’s holes farthest from the catheter tip, where obstruction has been thought to frequently occur. However, previous studies have relied on simplified geometries and idealized catheter positioning, limiting the ability to capture patient-specific anatomical variability. Segmental flow distribution in ventricular catheters was analyzed using ventricular models derived from pediatric patients with hydrocephalus. Two pediatric shunted patients and one pediatric externalized patient with varied sizes, ranging from enlarged (FOHR: 0.45), moderate (0.30), and small (0.29), were segmented from MRI scans and reconstructed into closed-volume 3D models. We simulated the insertion of a 4-row, 4-hole ventricular catheter using frontal, parietal, and occipital surgical approaches. A choroid plexus mimic modeled from confocal microscopy was attached to the ventricular system for inlet flow, and a constant flow rate of 0.35 mL/min was applied to simulate CSF flow inside the ventricular domain. Steady-state, laminar 3D computational fluid dynamics simulations were performed to quantify mass flow into each catheter drainage segment. Occipital placement consistently concentrated flow (> 81%) in the fourth (most distal) segment across all ventricular sizes. In contrast, frontal and parietal approaches showed variable flow distributions dependent on ventricular morphology. In the moderate ventricle, parenchymal contact obstructed distal holes, redirecting flow proximally (Segments 1–2: >99%). Segmental flow distribution was influenced by drainage hole patency, ventricular morphology, and catheter orientation. Altogether, these data suggest that anatomical or approach dependent shifts result in specific tissue contact changes and therefore change in flow distribution. A larger sample scale study is needed to understand variability resulting from heterogeneous catheter placement in varying ventricular morphologies.