Sgouros Spyros, Dipple Susan J
Department of Neurosurgery, Birmingham Children's Hospital, United Kingdom.
J Neurosurg. 2004 Mar;100(3):534-40. doi: 10.3171/jns.2004.100.3.0534.
Surveys of cerebrospinal fluid (CSF) shunts that have been removed from patients have shown that even when the ventricular catheter is the cause of the obstruction, the valve may be obstructed or underperforming. The aim of this pilot study was to investigate the degradation of shunt valve structure over time due to the deposition of debris. The findings were compared with findings in unused valves.
Scanning electron microscopy was used to visualize the structures of the valves. The items that were examined included two unused and nine explanted cylindrical medium pressure valves, one unused and six explanted Delta 1.5 valves (PS Medical, Goleta, CA), and one explanted Medos Programmable valve (Codman Johnson & Johnson, LeLocle, Switzerland). The valves were cut open, disassembled, and coated in gold. The areas that were analyzed included the main valve chamber, the diaphragm unit, and the antisiphon device. For areas with abnormal deposits, energy-dispersive x-ray microanalysis was performed to establish the chemical composition of the deposits. The reference unused valves had smooth surfaces with no deposits in any areas. All explanted valves had extensive deposits in all surveyed areas. The deposits varied from small clusters of crystals to large areas that displayed a cobblestone appearance. In diaphragm valves the deposits extensively affected the surface of the diaphragm and the gap between the diaphragm and the surrounding case, where normally CSF flows; in the Medos valve the deposits affected in the spring and "staircase" unit. Deposits were present as early as 2 weeks after implantation. On some valves there was a complete film covering the entire outlet of the valve, which formed a cast inside the valve stretching from wall to wall. The deposits consisted mostly of sodium and chloride, but occasionally contained calcium. In all infected and some noninfected valves there was a significant peak of carbon, indicating the presence of protein deposits.
It appears that the continuous flow of CSF through shunt valves causes surface deposits of sodium chloride and other crystals on all aspects of the valve, including the outlet pathways. The formation of deposits may be encouraged by the adhesive properties of the materials that constitute the valve parts.
对从患者体内取出的脑脊液（CSF）分流器进行的调查显示，即使脑室导管是梗阻的原因，阀门也可能被阻塞或性能不佳。这项初步研究的目的是调查由于碎片沉积导致分流阀结构随时间的降解情况。将研究结果与未使用过的阀门的结果进行比较。
使用扫描电子显微镜观察阀门的结构。检查的物品包括两个未使用过的和九个取出的圆柱形中压阀门、一个未使用过的和六个取出的Delta 1.5阀门（PS Medical，加利福尼亚州戈利塔）以及一个取出的Medos可编程阀门（科德曼强生公司，瑞士勒洛克勒）。将阀门切开、拆解并镀金。分析的区域包括主阀腔、隔膜单元和防虹吸装置。对于有异常沉积物的区域，进行能量色散X射线微分析以确定沉积物的化学成分。参考的未使用过的阀门表面光滑，任何区域均无沉积物。所有取出的阀门在所有调查区域都有大量沉积物。沉积物从小簇晶体到呈现鹅卵石外观的大面积区域不等。在隔膜阀中，沉积物广泛影响隔膜表面以及隔膜与周围壳体之间通常有脑脊液流动的间隙；在Medos阀中，沉积物影响弹簧和“阶梯”单元。沉积物最早在植入后2周出现。在一些阀门上，有一层完整的薄膜覆盖整个阀门出口，在阀门内部形成一个从壁到壁延伸的铸型。沉积物主要由钠和氯组成，但偶尔也含有钙。在所有感染的和一些未感染的阀门中，都有一个明显的碳峰，表明存在蛋白质沉积物。
看来脑脊液通过分流阀的持续流动会导致氯化钠和其他晶体在阀门的各个方面，包括出口通道上形成表面沉积物。构成阀门部件的材料的粘附特性可能会促进沉积物的形成。
