Faculty Collaboration Database

Effects of tissue preservation temperature on high strain-rate material properties of brain. J Biomech 2011 Feb 03;44(3):391-6

Date

11/09/2010

Pubmed ID

21055756

DOI

10.1016/j.jbiomech.2010.10.024

Scopus ID

2-s2.0-78651466766 (requires institutional sign-in at Scopus site)   41 Citations

Abstract

Postmortem preservation conditions may be one of factors contributing to wide material property variations in brain tissues in literature. The objective of present study was to determine the effects of preservation temperatures on high strain-rate material properties of brain tissues using the split Hopkinson pressure bar (SHPB). Porcine brains were harvested immediately after sacrifice, sliced into 2 mm thickness, preserved in ice cold (group A, 10 samples) and 37°C (group B, 9 samples) saline solution and warmed to 37°C just prior to the test. A SHPB with tube aluminum transmission bar and semi-conductor strain gauges were used to enhance transmitted wave signals. Data were gathered using a digital acquisition system and processed to obtain stress-strain curves. All tests were conducted within 4 h postmortem. The mean strain-rate was 2487±72 s(-1). A repeated measures model with specimen-level random effects was used to analyze log transformed stress-strain responses through the entire loading range. The mean stress-strain curves with ±95% confidence bands demonstrated typical power relationships with the power value of 2.4519 (standard error, 0.0436) for group A and 2.2657 (standard error, 0.0443) for group B, indicating that responses for the two groups are significantly different. Stresses and tangent moduli rose with increasing strain levels in both groups. These findings indicate that storage temperatures affected brain tissue material properties and preserving tissues at 37°C produced a stiffer response at high strain-rates. Therefore, it is necessary to incorporate material properties obtained from appropriately preserved tissues to accurately predict the responses of brain using stress analyses models, such as finite element simulations.

Author List

Zhang J, Yoganandan N, Pintar FA, Guan Y, Shender B, Paskoff G, Laud P

Authors

Purushottam W. Laud PhD Professor in the Institute for Health and Equity department at Medical College of Wisconsin
Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of Wisconsin
Narayan Yoganandan PhD Professor in the Neurosurgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Biomechanical Phenomena
Brain
Compressive Strength
Stress, Mechanical
Swine
Temperature
Tissue Preservation