Preliminary investigation of relationship between tearing force and tissue property in porcine aorta

With the rapid rate of technological advancement, a growing interest in the desire to increase the autonomy of robotic surgical systems has been reported. One of the major challenges in achieving this goal is transferring a skilled surgeon's ability into the system, especially the surgeon's adaptive tissue handling skill to prevent unwanted tissue damage. A model estimating tissue tearing force is therefore necessary for the implementation of this skill. However, to generate a model flexible enough for different types of tissues, a theoretical understanding of the biomechanical phenomena of tissue tearing is necessary. This paper focuses on investigating the biological tissue's tearing behavior through the comparison with polymeric materials. Tensile tests on trouser-shaped specimens harvested from porcine thoracic aorta were conducted. These specimens were harvested in three different angles (0°, 45°, 90°) relative to the blood flow to assess the biological tissue's anisotropic nature. We identified specific tearing patterns associated to the tensile direction. We also identified relation between the force required to tear the specimen and its elastic modulus. These results are discussed based on the elastin and collagen fibrous network configuration within the biological tissue.