Abstract

BACKGROUND

There have been few improvements in cerebrospinal fluid (CSF) shunt technology since John Holter introduced the silicon valve, with overdrainage remaining a major source of complications.

OBJECTIVE

To better understand why valves are afflicted by supra-normal CSF flow rates. We present in Vitro benchtop analyses of flow through a differential pressure valve under simulated physiological conditions.

METHODS

The pseudo-ventricle benchtop valve testing platform that comprises a rigid pseudo-ventricle, compliance chamber, pulsation generator, and pressure sensors was used to measure flow rates through a differential pressure shunt valve under the following simulated physiological conditions: orientation (horizontal/vertical), compliance (low/medium/high), and pulsation generator force (low/medium/high).

RESULTS

Our data show that pulse pressures are faithfully transmitted from the ventricle to the valve, that lower compliance and higher pulse generator forces lead to higher pulse pressures in the pseudo-ventricle, and that both gravity and higher pulse pressure lead to higher flow rates. The presence of a valve mitigates but does not eliminate these higher flow rates.

CONCLUSION

Shunt valves are prone to gravity-dependent overdrainage, which has motivated the development of gravitational valves and antisiphon devices. This study shows that overdrainage is not limited to the vertical position but that pulse pressures that simulate rhythmic (eg, cardiac) and provoked (eg, Valsalva) physiological CSF pulsations increase outflow in both the horizontal and vertical positions and are dependent on compliance. A deeper understanding of the physiological parameters that affect intracranial pressure and flow through shunt systems is prerequisite to the development of novel valves.

中文翻译：

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心室腹腔分流引流随着重力和脑脊液压力脉动而增加：台式模型

摘要

背景

自从 John Holter 推出硅阀以来，脑脊液 (CSF) 分流技术几乎没有什么改进，过度引流仍然是并发症的主要来源。

客观的

为了更好地理解为什么瓣膜会受到超正常脑脊液流速的影响。我们展示了在模拟生理条件下通过差压阀的流量的体外台式分析。

方法

伪心室台式瓣膜测试平台包括刚性伪心室、顺应性室、脉动发生器和压力传感器，用于在以下模拟生理条件下测量通过差压分流阀的流量：方向（水平/垂直） 、顺应性（低/中/高）和脉动发生器力（低/中/高）。

结果

我们的数据表明，脉压从心室忠实地传递到瓣膜，较低的顺应性和较高的脉冲发生器力会导致假心室中的脉压更高，而重力和更高的脉压都会导致更高的流速。阀门的存在减轻但不会消除这些较高的流速。

结论

分流阀容易发生依赖于重力的过度排水，这推动了重力阀和反虹吸装置的发展。这项研究表明，过度引流不仅限于垂直位置，而是模拟节律性（例如，心脏）和诱发（例如，Valsalva）生理 CSF 脉动的脉压增加水平和垂直位置的流出，并且取决于顺应性。深入了解影响颅内压和通过分流系统流量的生理参数是开发新型瓣膜的先决条件。