title: Characterization of pressure distribution in penetrating traumatic brain injuries.
abstract: Severe impacts to the head commonly lead to localized brain damage. Such impacts may also give rise to temporary pressure changes that produce secondary injuries in brain volumes distal to the impact site. Monitoring pressure changes in a clinical setting is difficult; detailed studies into the effect of pressure changes in the brain call for the development and use of animal models. The aim of this study is to characterize the pressure distribution in an animal model of penetrating traumatic brain injuries (pTBI). This data may be used to validate mathematical models of the animal model and to facilitate correlation studies between pressure changes and pathology. Pressure changes were measured in rat brains while subjected to pTBI for a variety of different probe velocities and shapes; pointy, blunt, and flat. Experiments on ballistic gel samples were carried out to study the formation of any temporary cavities. In addition, pressure recordings from the gel experiments were compared to values recorded in the animal experiments. The pTBI generated short lasting pressure changes in the brain tissue; the pressure in the contralateral ventricle (CLV) increased to 8 bar followed by a drop to 0.4 bar when applying flat probes. The pressure changes in the periphery of the probe, in the Cisterna Magna, and the spinal canal, were significantly less than those recorded in the CLV or the vicinity of the skull base. High-speed videos of the gel samples revealed the formation of spherically shaped cavities when flat and spherical probes were applied. Pressure changes in the gel were similar to those recorded in the animals, although amplitudes were lower in the gel samples. We concluded cavity expansion rate rather than cavity size correlated with pressure changes in the gel or brain secondary to probe impact. The new data can serve as validation data for finite element models of the trauma model and the animal and to correlate physical measurements with secondary injuries.
authors.affiliation: Applied Mechanics, Chalmers University of Technology , Göteborg , Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Davidsson
authors.affiliation: Department of Neuroscience, Karolinska Institute , Stockholm , Sweden.
authors.forename: Mårten
authors.initials: M
authors.lastname: Risling
keywords: TBI; experimental; penetrating traumatic brain injuries; pressure
references.citation: Acta Chir Scand Suppl. 1976;459:1-76
references.pmid: 1065166
references.citation: Lasers Surg Med. 2000;26(4):364-75
references.pmid: 10805941
references.citation: Forensic Sci Int. 2004 May 10;141(2-3):91-8
references.pmid: 15062946
references.citation: Stapp Car Crash J. 2007 Oct;51:81-114
references.pmid: 18278592
references.citation: Brain Inj. 2014;28(12 ):1491-503
references.pmid: 25111457
references.citation: Eur J Neurosci. 2005 Aug;22(4):973-85
references.pmid: 16115220
references.citation: Front Neurol. 2012 Apr 02;3:30
references.pmid: 22485104
references.citation: Arch Neurol. 1983 Jan;40(1):7-10
references.pmid: 6848098
references.citation: Ann Biomed Eng. 2011 Oct;39(10):2550-9
references.pmid: 21735320
references.citation: Neuroimage. 2011 Jan;54 Suppl 1:S89-97
references.pmid: 20493951
references.citation: J Neurotrauma. 2012 Apr 10;29(6):1219-32
references.pmid: 22181060
references.citation: Acta Neurochir (Wien). 2005 Jul;147(7):775-80; discussion 780
references.pmid: 15900397
references.citation: Arch Neurol. 1986 Aug;43(8):771-3
references.pmid: 3089201