Biomechanical characterisation of fresh and cadaverous human small intestine: applications for abdominal trauma

Intestinal injuries are responsible for significant morbidity and mortality arising from trauma to the abdomen. The biomechanical characterisation of the small intestine allows for the understanding of the pathophysiological mechanisms responsible for these injuries. Studies reported in the literature focus principally on quasi-static tests, which do not take into account the stresses experienced during high kinetic trauma. In addition, the use of embalmed human tissue can alter the recorded response. The stress-strain curves from 43 tensile tests performed at 1 m/s were analysed. Samples were prepared from four fresh human intestines and from four embalmed cadaveric intestines. The data indicated a two-phase response, with each response consisting of a quasi-linear increase in the stress followed by an inflection in the curve before a peak preceding the loss of stress. The fresh tissue was more deformable than the embalmed tissue, and its first peak stress was lower (P = 0.034). A complementary histological analysis was performed. The results of the analysis enable an investigation of the response of the intestinal wall layers to stress as a two-layer structure and highlight the high sensitivity of the structure's mechanical behaviour to the speed of loading and the method of preservation.