Title:
Impact of the defect size, the mesh overlap and the fixation depth on ventral hernia repairs: a combined experimental and numerical approach.

Abstract:
Ventral hernia repairs (VHRs) still exhibit clinical complications in terms of recurrence, pain, and discomfort. Factors such as surgical technique or mesh features are thought to be highly influent. The aim was to evaluate the impact of the defect size, the mesh overlap and the fixation depth on VHR using both physical and numerical models.
The physical model was developed to mimic a passive abdominal wall. Healthy, damaged, and repaired configurations were evaluated using a spherical plunger. The associated numerical (Finite Elements) model was first loaded by a plunger for validation. A parametric study was then conducted with the numerical model loaded by a uniform pressure. Two defect sizes (3.5 × 5 cm and 8.25 × 12 cm elliptic shape), two overlaps (2 and 5 cm), and two fixation depths (peritoneum or muscle) were investigated for both passive and active abdominal walls.
With the physical model, the repaired configuration was 22 % stiffer than the damaged configuration. The statistical analysis of the parametric study showed that the defect size was the most influential parameter regarding the stress in the mesh, the bulging and the pull-out force at the fixation points. The overlap was influential in terms of stress in the mesh. The fixation depth was not influential. These trends increased with the abdominal wall activity.
Increase of the defect size and decrease of the overlap affected significantly the VHR mechanical performances. Such numerical models could help to better understand the behavior of the repaired abdominal wall and finally to reduce the clinical complications.