Unpredictable tensile strength biomechanics may limit thawed cadaver use for simulant research

Abstract

A series of tensile strength experiments were conducted using an un-embalmed elderly 91-year-old female cadaver, who had been frozen and thawed on five occasions. One sample was taken from the heart, kidney, oesophagus, skeletal muscle, ascending aorta, trachea, spleen, liver, lung, pancreas, pericardium, skin (abdomen) and skin (thorax) and the tensile strengths were measured using universal test equipment – Hounsfield H50KM (Hounsfield Test Equipment Ltd, Surrey, UK). Tensile strengths were: heart 34.9 Pa, spleen 45.6 Pa, kidney 100.7 Pa, liver 106.2 Pa, pancreas 148.9 Pa, oesophagus 216.5 Pa, skeletal muscle 288.9 Pa, lung 293.6 Pa, ascending aorta 588.2 Pa, pericardium 1341.9 Pa, trachea 1523.9 Pa, skin (abdomen) 3483.9 Pa, and skin (thorax) 3999.9 Pa. Compared with published values for fresh cadavers (that are only available for certain tissues), some organs and tissues had tensile strengths that fell well below the normal range (heart, oesophagus and ascending aorta), compared with others where the tensile strengths were well above the normal range (kidney and skeletal muscle). Only one tissue, from the trachea, fell within the normal range. The remainder of the data gave relative tensile strengths of other organs and tissues with the spleen being the least, and skin being the most, elastic tissue. Freezing and thawing cadaveric organs and tissues may alter their physical properties in ways that are not predicable, with both increases and decreases in tensile strength. Although this pilot study allows the relative tensile strengths of such tissues to be compared, it also demonstrates that physical changes following freezing and thawing alter properties in such a way that its usefulness as a simulant for normal tissues may be limited.

Keywords:

• cadaver
• tensile strength
• frozen
• thawed
• simulant
• biomechanics