CSF dynamic analysis of a predictive pulsatility-based infusion test for normal pressure hydrocephalus
- 428 Downloads
Disturbed cerebrospinal fluid (CSF) dynamics are part of the pathophysiology of normal pressure hydrocephalus (NPH) and can be modified and treated with shunt surgery. This study investigated the contribution of established CSF dynamic parameters to AMPmean, a prognostic variable defined as mean amplitude of cardiac-related intracranial pressure pulsations during 10 min of lumbar constant infusion, with the aim of clarifying the physiological interpretation of the variable. AMPmean and CSF dynamic parameters were determined from infusion tests performed on 18 patients with suspected NPH. Using a mathematical model of CSF dynamics, an expression for AMPmean was derived and the influence of the different parameters was assessed. There was high correlation between modelled and measured AMPmean (r = 0.98, p < 0.01). Outflow resistance and three parameters relating to compliance were identified from the model. Correlation analysis of patient data confirmed the effect of the parameters on AMPmean (Spearman’s ρ = 0.58–0.88, p < 0.05). Simulated variations of ±1 standard deviation (SD) of the parameters resulted in AMPmean changes of 0.6–2.9 SD, with the elastance coefficient showing the strongest influence. Parameters relating to compliance showed the largest contribution to AMPmean, which supports the importance of the compliance aspect of CSF dynamics for the understanding of the pathophysiology of NPH.
KeywordsCerebrospinal fluid dynamics Prognostic tests Intracranial pressure Normal pressure hydrocephalus
This project was financed by the Swedish Research Council, VINNOVA, and the Swedish Foundation for Strategic Research through their common initiative: “Biomedical engineering for improved health”; and by the European Union through ERDF: Objective 2, Northern Sweden.
- 2.Andersson K, Manchester IR, Laurell K, Cesarini K, Malm J, Eklund A (2013) Measurement of CSF dynamics with oscillating pressure infusion. Acta Neurol Scand 128(1):17–23Google Scholar
- 10.Bradley WG, Scalzo D, Queralt J, Nitz WN, Atkinson DJ, Wong P (1996) Normal-pressure hydrocephalus: evaluation with cerebrospinal fluid flow measurements at mr imaging. Neuroradiology 198:523–529Google Scholar
- 12.Czosnyka M, Czosnyka Z, Keong N, Lavinio A, Smielewski P, Momjian S, Schmidt EA, Petrella G, Owler B, Pickard JD (2007) Pulse pressure waveform in hydrocephalus : what it is and what it isn’t. Neurosurg Focus 22:1–7Google Scholar
- 13.Davson H (1966) Formation and drainage of the cerebrospinal fluid. Sci Basis Med Annu Rev 1966:238–259 Google Scholar
- 24.Malm J, Sundström N, Cesarini KG, Edsbagge M, Kristensen B, Leijon G, Eklund A (2012) Implementation of a new CSF dynamic device: a multicenter feasibility study in 562 patients. Acta Neurol Scand 125(3):199–205Google Scholar