Contribution of the skin, rectus abdominis and their sheaths to the structural response of the abdominal wall ex vivo
Résumé
A better understanding of the abdominal wall biomechanics could help designing new treatments for incisional hernia. In the current study, a new experimental protocol was developed to evaluate the contributions of the abdominal wall components to the mechanical response of the anterior part of the abdominal wall. The specimens underwent 3 dissections (removal of 1: skin and subcutaneous fat, 2: anterior rectus sheath, 3: rectus abdominis muscles). After each dissection, they were subjected to air pressure up to 0.03 bar. Ultrasound images and associated elastographic maps were collected at 0, 0.02 and 0.03 bar in the intact state and strains on the internal surface were calculated using stereo-correlation in all states. Strains of the rectus abdominis and linea alba are analyzed. After the dissection of the anterior sheath of the rectus abdominis, longitudinal strain is found significantly different in the linea alba and on the rectus abdominis area. The current results highlight the importance of the muscle sheath in the mechanical response of the anterior part of the abdominal wall ex vivo. Geometrical characteristics such as thickness and radii of curvature and mechanical properties (shear modulus of the rectus abdominis) are provided in order to facilitate future modeling efforts.