A novel in vivo approach to assess strains of the human abdominal wall under known intraabdominal pressure

Abstract

The study concerns mechanical behaviour of a living human abdominal wall.A better mechanical understanding of a human abdominal wall and recognition of its material properties is required to find mechanically compatible surgical meshes to significantly improve the treatment of ventral hernias.A non-invasive methodology, based on in vivo optical measurements is proposed to determine strains of abdominal wall corresponding to a known intraabdominal pressure. The measurement is performed in the course of a standard procedure of peritoneal dialysis. A dedicated experimental stand is designed for the experiment. The photogrammetric technique is employed to recover the three-dimensional surface geometry of the anterior abdominal wall at the initial and terminal instants of the dialysis. This corresponds to two deformation states, before and after filling the abdominal cavity with dialysis fluid.The study provides information on strain fields of living human abdominal wall. The inquiry is aimed at principal strains and their directions, observed at the level from -10% to 17%. The intraabdominal pressure related to the amount of introduced dialysis fluid measured within the medical procedure covers the

Nonlinear material identification of heterogeneous isogeometric Kirchhoff-Love shells

“…The membrane and bending energy split favors combining and studying different material models, while the proposed discretization allows local mesh refinement that can accurately account for expected material variations and discontinuities. In this manner we plan to apply the proposed inverse methodology to the material identification of human abdominal wall tissue based on the in-vivo measurements of Lubowiecka et al (2021). Furthermore, thick and composite shell formulations with various constraints (contact, volume, area) can be used.…”