降低脑积水分流管翻修率：关于导管孔设计的计算流体动力学研究

中文摘要 AI 辅助

近端分流管阻塞是儿童脑积水脑室-腹腔（VP）分流失败的主要原因，且与引流孔附近的壁面剪切环境密切相关。我们使用计算流体动力学（COMSOL）将局部壁面剪切应力（WSS）控制（通过导管尖端几何形状）与整体引流控制（通过阀门开口）解耦。在层流纳维-斯托克斯流动下，求解了具有牛顿脑脊液（ρ = 1000 kg/m³，μ = 1 mPa·s）和 ΔP ≈ 10 mmHg 的圆柱形脑室域，同时扫描远端孔间距、孔数量/直径以及简化的阀门收缩。实现了网格无关性（最小单元尺寸 ≈ 0.021 mm；远端孔速度收敛至 ≈ 1.18×10⁻³ m/s）。两个最远端孔的垂直分离使总流出量增加约 22%（2 mm 对比 0.5 mm），并使远端侧壁 WSS 提高约 19%，而上游孔的纵向移动仅产生微小变化。约 0.166-0.17 mm 的阀门开口将各几何形状下的系统引流设置为约 20 mL/h，表明容量受阀门限制，而局部 WSS 受几何形状控制。所选尖端使用四排、间距 1.4 mm 的两个锥形孔（内径 0.5 mm），将 WSS 集中在远端侧壁（即发生阻塞的表面），且不超过临床引流目标。这些发现提供了设计规则：优先考虑远端孔对间距，减少孔数量并使用更小的锥形开口以提高保护性 WSS，并通过阀门调节流出量。该框架为台架验证、在映射 WSS 下进行长期粘附测定以及解剖学真实的 CFD 提供了清晰路径。

英文摘要

Proximal shunt obstruction is the leading cause of ventriculoperitoneal (VP) shunt failure in pediatric hydrocephalus and is closely tied to the near-wall shear environment at drainage holes. We used computational fluid dynamics (COMSOL) to decouple local wall-shear-stress (WSS) control via catheter-tip geometry from global drainage control via a valve opening. A cylindrical ventricle domain with Newtonian CSF ($ρ$ = 1000 kg/m$^3$, $μ$ = 1 mPa$\cdot$s) and $ΔP \approx$ 10 mmHg was solved under laminar Navier-Stokes flow while sweeping distal hole spacing, hole count/diameter, and a simplified valve constriction. Mesh-independence was achieved (minimum element size $\approx$ 0.021 mm; distal-hole velocity converged to $\approx$ 1.18$\times10^{-3}$ m/s). Perpendicular separation of the two most distal holes increased total outflow by $\approx$ 22% (2 mm vs 0.5 mm) and raised distal lateral-wall WSS by $\approx$ 19%, whereas longitudinal shifts of upstream holes produced only small changes. A valve opening near 0.166-0.17 mm set system drainage to $\approx$ 20 mL/h across geometries, indicating capacity is valve-limited while local WSS is geometry-controlled. The selected tip uses two conical holes (0.5 mm ID) in four rows with 1.4 mm spacing, concentrating WSS at the distal lateral walls, the surfaces where obstruction occurs, without exceeding clinical drainage targets. These findings yield design rules: prioritize distal-pair spacing, reduce hole count with smaller conical openings to elevate protective WSS, and regulate outflow with the valve. The framework provides a clear path to benchtop validation, long-term adhesion assays under mapped WSS, and anatomically realistic CFD.

发表机构

• Johns Hopkins University（约翰霍普金斯大学）
• Columbia University（哥伦比亚大学）
• University of Michigan（密歇根大学）

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