Lin Julian, Morris Martin, Olivero William, Boop Frederick, Sanford Robert A
Department of Neurosurgery, University of Illinois College of Medicine, Peoria, USA.
J Neurosurg. 2003 Aug;99(2):426-31. doi: 10.3171/jns.2003.99.2.0426.
The treatment of hydrocephalus with shunt insertion is fraught with high failure rates. Evidence indicates that the proximal holes in a catheter are the primary sites of blockage. The authors have studied ventricular catheter designs by using computational fluid dynamics (CFD), two-dimensional water table experiments, and a three-dimensional (3D) automated testing apparatus together with an actual catheter. With the CFD model, the authors calculated that 58% of the total fluid mass flows into the catheter's most proximal holes and that greater than 80% flows into the two most proximal sets of holes within an eight-hole catheter. In fact, most of the holes in the catheters were ineffective. These findings were experimentally verified using two completely different methodologies: a water table model of a shunt catheter and a 3D automated testing apparatus with an actual catheter to visualize flow patterns with the aid of ink. Because the majority of flow enters the catheter's most proximal holes, blockages typically occur at this position, and unlike blockages at distal holes, occlusion of proximal holes results in complete catheter failure. Given this finding, new designs that incorporated varying hole pattern distributions and size dimensions of the ventricular catheter were conceived and tested using two models. These changes in the geometrical features significantly changed the entering mass flow rate distribution. In conclusion, new designs in proximal ventricular catheters with variable hole diameters along the catheter tip allowed fluid to enter the catheter more uniformly along its length, thereby reducing the probability of its becoming occluded.
采用分流管插入术治疗脑积水，失败率很高。有证据表明，导管近端的孔是堵塞的主要部位。作者通过计算流体动力学（CFD）、二维水位实验、三维（3D）自动测试装置以及实际导管，对脑室导管设计进行了研究。利用CFD模型，作者计算得出，总流体质量的58%流入导管最近端的孔，在八孔导管中，超过80%的流体流入最近端的两组孔。实际上，导管中的大多数孔并无作用。这些发现通过两种完全不同的方法得到了实验验证：一种是分流导管的水位模型，另一种是带有实际导管的3D自动测试装置，借助墨水来观察流动模式。由于大部分流体进入导管最近端的孔，堵塞通常发生在这个位置，与远端孔堵塞不同，近端孔堵塞会导致导管完全失效。鉴于这一发现，构思了采用不同孔型分布和尺寸的脑室导管新设计，并使用两种模型进行了测试。这些几何特征的变化显著改变了进入的质量流率分布。总之，沿导管尖端具有可变孔径的近端脑室导管新设计，使流体能够沿导管长度更均匀地进入导管，从而降低了导管堵塞的可能性。
