Stoma location and Parastomal Hernia. A Virtual Simulation Approach.

An ostomy is a surgical procedure by which an artificial opening in the abdominal wall, known as a stoma, is created. We assessthe effects of stoma location on the abdominal wall mechanics. We perform three–dimensional finite element simulations on ananatomy model which was generated on the basis of medical images. Our simulation methodology is entirely based on opensource software. We consider seventeen different locations for the stoma incision (trephine) and we simulate the mechanicalresponse of the abdominal wall when an intraabdominal pressure as high as 20 kPa is applied. We focus on factors relatedto the risk of parastomal hernia development such as the deformation experienced by the abdominal wall, the stress levelssupported by its tissues and the corresponding level of trephine enlargement.No significant dependence was found between stoma location and the levels of abdominal wall deformations or stress supportedby tissues, except for the case with a stoma located on the linea alba. Trephine perimeter and area respectively increased byas much as 44% and 85%. The level of trephine deformation depends on stoma location with considerably higher trephineenlargements found in stomas laterally located with respect to the rectus abdominis muscle.