Abstract
Intracranial pressure is mainly considered to be hydrostatic pressure, but observations demonstrated that ICP is heterogeneous within brain suggesting the presence of a solid pressure. Brain tissue is a biphasic material composed of solid and fluid phases. We hypothesized that in a saturated porous model, fluid and solid phases yielded two pressures. Our brain model was 0.5% agar gel. A quasi static compression was applied using a tensile machine. Pressures were gauged within the gel using two different microsensors. One sensor (A) has an open sensitive area measuring the total pressure, whereas the other sensor (B) has a pressure-sensitive area design that gauges mainly the fluid pressure. There was very good agreement between the pressure applied to the gel and the pressure inside the gel measured with sensor A. However, sensor B systematically underestimated the pressure in the gel. We assume that sensor A gauged the total pressure, which is the sum of the pore fluid pressure and mechanical stress, whereas sensor B probably measured only the fluid pressure. The difference between the two sensors reflects the solid part of the total pressure. ICP has to be considered to be the sum of fluid pressure and solid stress.
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References
Czosnyka M, Czosnyka Z, Pickard JD (1996) Laboratory testing of 3 ICP microtransducers. Neurosurgery 38:219–225
Gefen A, Margulies SS (2004) Are in vivo and in situ brain tissues mechanically similar? J Biomech 37:1339–1352
Hakim S, Venegas JG, Burton JD (1976) The physics of the cranial cavity, hydrocephalus and normal pressure hydrocephalus: mechanical interpretation and mathematical model. Surg Neurol 5:187–210
Miller JD (1989) Measuring ICP in patients ± its value now and in future? In: Hoff JT, Betz AL (eds) Intracranial pressure, vol 7. Springer, Berlin/Heidelberg/New York/Tokyo, pp 5–15
Miller K, Chinzei K, Orssengo G, Bednarz P (2000) Mechanical properties of brain tissue in-vivo: experiment and computer simulation. J Biomech 33:1369–1376
Momjian S, Bichsel D (2008) Nonlinear poroplastic model of ventricular dilatation in hydrocephalus. J Neurosurg 109:100–107
Normand V, Lootens DL, Amici E, Plucknett KP, Aymard P (2000) New insight into agarose gel mechanical properties. Biomacromolecules 1:730–738
Peña A, Bolton MD, Whitehouse H, Pickard JD (1999) Effects of brain ventricular shape on periventricular biomechanics: a finite element analysis. Neurosurgery 45:107–118
Piek J, Plewe P, Bock WJ (1988) Intrahemispheric gradients of brain tissue pressure in patients with brain tumours. Acta Neurochir 93:129–132
Roth S, Raul JS, Ludes B, Willinger R (2007) Finite element analysis of impact and shaking inflicted to a child. Int J Legal Med 121:223–228
Sahuquillo J, Poca MA, Arribas M, Garnacho A, Rubio E (1999) Interhemispheric supratentorial intracranial pressure gradients in head injured patients: are they clinically important? J Neurosurg 1:16–26
Symon L, Pasztor E, Branston NM, Dorsch NWC (1974) Effect of supratentorial space occupying lesions on regional intracranial pressure and local cerebral blood flow: experimental study in baboons. J Neurol Neurosurg Psychiatry 37:617–626
Wolfla CE, Luerssen TG, Bowman RM (1996) Brain tissue pressure gradients created by expanding frontal mass lesion. J Neurosurg 84:642–647
Acknowledgement
The authors wish to acknowledge the Academic Neurosurgical Unit at Addenbrooke’s Hospital, University of Cambridge Clinical School, and especially Dr. Alonso Pena as an author of the concept of the experiment.
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We declare that we have no conflict of interest.
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Ros, M., Yameogo, P., Payoux, P., Swider, P., Schmidt, E. (2012). Is ICP Solid or Fluid? In Vitro Biomechanical Model Using a Fluid-Saturated Gel. In: Schuhmann, M., Czosnyka, M. (eds) Intracranial Pressure and Brain Monitoring XIV. Acta Neurochirurgica Supplementum, vol 114. Springer, Vienna. https://doi.org/10.1007/978-3-7091-0956-4_17
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DOI: https://doi.org/10.1007/978-3-7091-0956-4_17
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