Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, WC1N 3BG, London, UK. linda.d'
UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK. linda.d'
Acta Neurochir (Wien). 2020 Oct;162(10):2451-2458. doi: 10.1007/s00701-020-04462-y. Epub 2020 Jun 24.
The hydrodynamics of cerebrospinal fluid shunts have been described in vitro; however, knowledge on the response of intracranial pressure (ICP) to valve settings adjustments in vivo is limited. This study describes the effect of adjusting the shunt valve setting on ICP in a cohort of patients with complex symptom management.
Single-centre retrospective observational study. Patients who underwent ICP-guided valve setting adjustments during 24-h continuous ICP monitoring, between 2014 and 2019, were included. Patients with suspected shunt malfunction were excluded. Median night ICP before and after the valve adjustments were compared (Δ night ICP). The responses of ICP to valve adjustment were divided into 3 different groups as follows: expected, paradoxical and no response. The frequency of the paradoxical response and its potential predicting factors were investigated.
Fifty-one patients (37 females, 14 males, mean age 38 years) receiving 94 valve setting adjustments met the study inclusion criteria. Patients' underlying conditions were most commonly hydrocephalus (47%) or idiopathic intracranial hypertension (43%). The response of ICP to valve setting adjustments was classified as 'expected' in 54 cases (57%), 'paradoxical' in 17 cases (18%) and 'no effect' (Δ night ICP < 1 mmHg) in 23 cases (24%). There was a significant correlation between the Δ night ICP and the magnitude of valve setting change in both the investigated valves (Miethke ProGAV, p = 0.01 and Medtronic Strata, p = 0.02).
Paradoxical ICP changes can occur after shunt valve setting adjustments. This observation should be taken into account when performing ICP-guided valve adjustments and is highly relevant for the future development of "smart" shunt systems.
脑积液分流器的流体动力学已在体外进行了描述；然而，关于颅内压（ICP）对体内阀门设置调整反应的知识有限。本研究描述了在一组具有复杂症状管理的患者中，调整分流器阀门设置对 ICP 的影响。
单中心回顾性观察性研究。纳入 2014 年至 2019 年间，在 24 小时连续 ICP 监测期间接受 ICP 引导的阀门设置调整的患者。排除怀疑分流器故障的患者。比较阀门调整前后的夜间 ICP 中位数（Δ夜间 ICP）。将 ICP 对阀门调整的反应分为 3 个不同的组：预期、反常和无反应。研究了反常反应的频率及其潜在的预测因素。
51 名患者（37 名女性，14 名男性，平均年龄 38 岁）接受了 94 次阀门设置调整，符合研究纳入标准。患者的基础疾病最常见的是脑积水（47%）或特发性颅内高压（43%）。ICP 对阀门设置调整的反应分类为“预期”54 例（57%），“反常”17 例（18%）和“无效应”（Δ夜间 ICP<1mmHg）23 例（24%）。在研究的两种阀门中，Δ夜间 ICP 与阀门设置变化幅度之间存在显著相关性（Miethke ProGAV，p=0.01 和 Medtronic Strata，p=0.02）。
分流器阀门设置调整后可能会出现反常的 ICP 变化。在进行 ICP 引导的阀门调整时，应考虑到这一观察结果，这对未来“智能”分流器系统的发展具有重要意义。
