Testing of cerebrospinal compensatory reserve in shunted and non-shunted patients: a guide to interpretation based on an observational study.

Czosnyka, Marek; Whitehouse, Helen; Smielewski, Peter; Šimac, S.; Pickard, John D.

doi:10.1136/jnnp.60.5.549

Cited by 116 publications

(86 citation statements)

References 45 publications

(20 reference statements)

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“…After the description of NPH by Hakim and Adams (2) many authors have developed clinical tests for measuring the capacity for CSF resorption, aiming at selecting patients for shunt surgery (1,(3)(4)(5)(6). Thus Hussey et al found that a plateau pressure (P pl ) above 22 mmHg reached during a constant rate of infusion (0.76 ml/min) in the lumbar spinal CSF space could be used as selection criterion for shunt surgery (7).…”

Section: Lumbar Infusion Test In Normal Pressure Hydrocephalusmentioning

confidence: 99%

“…the amplitude at the plateau; the time to reach the steady-state plateau pressure level (T pl , min) as well as the total infusion time (T inf , min). Resistance to outflow (R out ) was calculated as (P pl ) P in )/ infusion rate, mmHg/ml/min (1,6,8,9).…”

Section: Calculations and Statisticsmentioning

confidence: 99%

“…A decreased compliance with restriction of the compensatory reserves is assumed to be involved in the development of NPH symptoms (6,14). Therefore, we calculated the rate of pressure increase before reaching the steady-state plateau and measured the pulse-pressure amplitude at the plateau level as estimates of the compensatory reserves in these patients.…”

Section: Measures Of Compliancementioning

confidence: 99%

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Lumbar infusion test in normal pressure hydrocephalus

2005

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Section: Lumbar Infusion Test In Normal Pressure Hydrocephalusmentioning

confidence: 99%

Section: Calculations and Statisticsmentioning

confidence: 99%

Section: Measures Of Compliancementioning

confidence: 99%

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Lumbar infusion test in normal pressure hydrocephalus

2005

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“…Patients with pressure differential devices often suffer excessive negative IVP in the upright position (Table 3), 3,6,11) which is thought to be important in the development of overdrainage. 4,16) Selection of a high shunt opening pressure may reduce the risk of overdrainage in the upright position, but also increases the risk of underdrainage in the supine position. In contrast, the DSV provides different opening pressures depending on the patient's posture.…”

Section: Discussionmentioning

confidence: 99%

Clinical Experience With a Dual Switch Valve (Miethke) for the Management of Adult Hydrocephalus

Tsunoda

Maruki

2007

Neurol. Med. Chir.(Tokyo)

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The dual switch valve (DSV), which switches between two parallel valve chambers depending on the patient posture, was evaluated in 101 consecutive adult patients with hydrocephalus who required shunt surgery. The opening pressure was 5 or 10 cmH 2 O for the supine position and 30 or 40 cmH 2 O for the upright position depending on the sitting height. The results clearly showed that the DSV can regulate the intraventricular pressure (IVP) to 5 to 10 cmH 2 O in the supine and almost zero in the upright position, independently of posture. Ninety-four of the 101 patients received the DSV and 86 patients showed some clinical improvement. However, three patients required irrigation of subdural hematoma and six were thought to suffer underdrainage (4 probable and 2 possible). Such underdrainage probably resulted from the relatively high opening pressure in the supine position of 10 cmH 2 O and the bedridden state of these patients. This problem may be solved by the DSV with the 5 cmH 2 O setting in the supine position. The DSV can maintain physiological IVP in hydrocephalic patients independently of posture and provides generally satisfactory clinical outcome, but cannot prevent all inadequate drainage-related problems.

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“…In NPH and in ageing, there is evidence for both an alteration in CSF production and a decrease in the CSF absorption [31][32][33]. Even the CSF secretion is shown to be impaired in experimentally induced hydrocephalus using kaolin [34].…”

Section: Comparison With In Vivo Factsmentioning

confidence: 99%

Ventricle Equilibrium Position in Healthy and Normal Pressure Hydrocephalus Brains Using an Analytical Model

Shahim¹,

Drezet

Martin

et al. 2012

Journal of Biomechanical Engineering

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The driving force that causes enlargement of the ventricles remains unclear in case of normal pressure hydrocephalus (NPH). Both healthy and NPH brain conditions are characterized by a low transparenchymal pressure drop, typically 1 mm Hg. The present paper proposes an analytical model for normal and NPH brains using Darcy's and Biot's equations and simplifying the brain geometry to a hollow sphere with an internal and external radius. Self-consistent solutions for the large deformation problem that is associated with large ventricle dilation are presented and the notion of equilibrium or stable ventricle position is highlighted for both healthy and NPH conditions. The influence of different biomechanical parameters on the stable ventricle geometry is assessed and it is shown that both CSF seepage through the ependyma and parenchymal permeability play a key role. Although very simple, the present model is able to predict the onset and development of NPH conditions as a deviation from healthy conditions.

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Testing of cerebrospinal compensatory reserve in shunted and non-shunted patients: a guide to interpretation based on an observational study.

Abstract: The appendix presents an introduction to the mathematical modelling of CSF pressure volume-compensation included in computerised infusion test software.

Cited by 116 publications

References 45 publications

Lumbar infusion test in normal pressure hydrocephalus

Lumbar infusion test in normal pressure hydrocephalus

Clinical Experience With a Dual Switch Valve (Miethke) for the Management of Adult Hydrocephalus

Ventricle Equilibrium Position in Healthy and Normal Pressure Hydrocephalus Brains Using an Analytical Model

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