An experimental and analytical approach to the development of a range of neurovascular trauma indices

Boock, Robert J.<sup>1</sup>; Thibault, Lawrence E.<sup>1</sup>

Affiliations

¹Department of Bioengineering, University of Pennsylvania, 114 Hayden Hall, Philadelphia, PA 19104, USA

Abstract

Results from isolated blood vessel studies show a graded physiologic response to a mechanical stretch injury. The measured response shows a developed force post injury ranging from 2 to 7 grams. This corresponds to a decrease in diameter of approximately 7-12%.

An appropriately scaled materials testing device has been developed. This device consists of a solenoid driver, an isomeuic force transducer, an angular displacement transducer, as well as a fluid reservoir system.

A series of experiments involving dynamic elongation of fluid and air filled elastic tubes have been conducted together with the specimens of viable blood vessels. The polymer tube physical model allows us to more closely study the coupled fluid and solid mechanics problem associated with cerebral blood vessels undergoing high strain rate loading. These strains are comparable to those associated with traumatic head injuries. Comparisons between fluid and air filled elastic tubes show increased force measurements ranging from 10 to 43%. Using both physical and analytical models we can investigate the thresholds for a vasoreactive response (below the threshold for structural failure) elicited by mechanical loading of the head. It is felt that this response is elicited during impact and leads to a vasospasm; the concomitant decrease in cerebral blood flow can exacerbate the neural injury sustained.

Cited Works (3)

Year	Entry
1989	Gennarelli TA, Thibault LE, Tipperman R, Tomei G, Sergot R, Brown M, Maxwell WL, Graham DI, Adams JH, Irvine A, Gennarelli LM, Duhaime AC, Boock R, Greenberg J. Axonal injury in the optic nerve: a model simulating diffuse axonal injury in the brain. J Neurosurg. August 1989;71(2):244-253.
1979	Fung YC, Fronek K, Patitucci P. Pseudoelasticity of arteries and of its mathematical expression. Am J Physiol. 1979;237(5):H620-H631.
1982	Gennarelli TA, Thibault LE, Adams JH, Graham DI, Thompson CJ, Marcincin RP. Diffuse axonal injury and traumatic coma in the primate. Ann Neurol. 1982;12(6):564-574.

Cited By (7)

Year	Entry
1991	Thomas P, Bradford M, Ward E. The cause of head injuries in real world crashes. In: Proceedings of the 13th International Technical Conference on Experimental Safety Vehicles (ESV). November 4-7, 1991; Paris, France.67-77.
1992	Cargill RS, Thibault LE. The use of in vitro models for neural injury with superimposed hypoxia in the development of new head injury tolerance criteria. In: Proceedings of the 1992 International IRCOBI Conference on the Biomechanics of Impact. September 9-11, 1992; Verona, Italy.203-212.
2003	Monson KL, Goldsmith W, Barbaro NM, Manley GT. Axial mechanical properties of fresh human cerebral blood vessels. J Biomech Eng. April 2003;125(2):288-294.
1996	Cargill RS II, Thibault LE. Acute alterations in [Ca²⁺]_i in NG108-15 cells subjected to high strain rate deformation and chemical hypoxia: an in vitro model for neural. J Neurotrauma. July 1996;13(7):395-407.
1992	Mendis K. Finite Element Modeling of the Brain to Establish Diffuse Axonal Injury Criteria [PhD thesis]. The Ohio State University; November 1992.
1991	Barbee KA. Cellular Response of Vascular Smooth Muscle to Mechanical Stimuli [PhD thesis]. Philadelphia, PA: University of Pennsylvania; 1991.
1994	Bilston LE. The Biomechanics of the Spinal Cord During Traumatic Spinal Cord Injury [PhD thesis]. Philadelphia, PA: University of Pennsylvania; 1994.