Czosnyka Z H, Czosnyka M, Richards H K, Pickard J D
United Kingdom Shunt Evaluation Laboratory, Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge, England.
Neurosurgery. 2001 Mar;48(3):689-93; discussion 693-4. doi: 10.1097/00006123-200103000-00052.
To assess the long-term hydrodynamic properties of a new cerebrospinal fluid flow-regulating hydrocephalus shunt called the CRx Diamond valve (Phoenix Biomedical Corp., Valley Forge, PA).
Three samples of a Diamond valve were tested in the United Kingdom Shunt Evaluation Laboratory during a 40-day period. Tests were performed for long-term pressure-flow performance, overdrainage, susceptibility to ambient temperature changes, external pressure, reflux, presence of small particles in the reagent, mechanical durability, and magnetic resonance imaging compatibility.
Tests demonstrated that the Diamond valve stabilized flow within the range of 0.36 to 0.62 ml/min when pressure varied from 14 to 23 mm Hg. Hydrodynamic resistance demonstrated pressure-dependent variability from 20 to 78 mm Hg/(ml/min). The time drift of hydrodynamic parameters was significant (P < 0.001). The valve was insensitive to changes in temperature, external pressure, rapid fluctuations of differential pressure, small particles in fluid, and reflux.
The Diamond valve demonstrated the intended variable resistance, which increased as the pressure increased. This property may help it limit overdrainage related to body posture as well as nocturnal vasogenic waves. Flow through the valve stabilizes within a wide range, which may contribute to the prevention of excessive pressure buildup after implantation. However, shunt placement should be avoided in patients who present with normal baseline intracranial pressure but an increased incidence of high vasogenic intracranial pressure waves.
评估一种名为CRx Diamond瓣膜（菲尼克斯生物医学公司，宾夕法尼亚州福吉谷）的新型脑脊液流量调节脑积水分流器的长期流体动力学特性。
在英国分流评估实验室对三个Diamond瓣膜样本进行了为期40天的测试。测试内容包括长期压力-流量性能、过度引流、对环境温度变化的敏感性、外部压力、反流、试剂中存在小颗粒、机械耐久性以及磁共振成像兼容性。
测试表明，当压力在14至23毫米汞柱之间变化时，Diamond瓣膜使流量稳定在0.36至0.62毫升/分钟的范围内。流体动力阻力显示出压力依赖性变化，范围为20至78毫米汞柱/（毫升/分钟）。流体动力学参数的时间漂移显著（P < 0.001）。该瓣膜对温度变化、外部压力、压差快速波动、流体中的小颗粒和反流不敏感。
Diamond瓣膜显示出预期的可变阻力，该阻力随压力增加而增大。这一特性可能有助于限制与身体姿势以及夜间血管源性波动相关的过度引流。通过该瓣膜的流量在很宽的范围内稳定，这可能有助于预防植入后压力过度升高。然而，对于基线颅内压正常但血管源性颅内压波发生率增加的患者，应避免放置分流器。
