Etiological analysis of parastomal hernia by computed tomography examination

Introduction
Parastomal hernia is a common complication after stoma formation. The definitive risk factors for parastomal hernia development remain unclear.

Aim
This study evaluated the risk factors through computed tomography (CT) scan of patients with parastomal hernia.

Material and methods
All patients who underwent an operation at our institution from January 2008 to February 2014 were included. We recorded patient-related and operation-related variables, and CT scans were checked. All the variables were analyzed with SPSS 19 to identify the risk factors for parastomal hernia formation.

Results
Of the 128 patients who underwent colostomy, 49 (38.3%) developed a parastomal hernia during a median follow-up period of 20.1 months (range: 4–84 months). Hernia development was significantly associated with the thickness of subcutaneous fat in the abdominal wall, the location of the stoma, anteroposterior diameter and horizontal diameter of the body. The defect size of the abdominal wall is another risk factor. The larger the defect size of the abdominal wall, the larger is the parastomal stoma (3.79 ±1.51 vs. 2.13 ±0.74 cm horizontally and 4.90 ±2.25 vs. 2.94 ±0.73 cm vertically, p < 0.001). The hernia contents protrude into the hernial sac through the path of the inner side more than the outer side (77.6% vs. 12.2%).

Conclusions
Our findings in Chinese patients with parastomal hernia match those from Western countries: obesity, the location of the stoma, and the defect size of the abdominal wall are significant risk factors for parastomal hernia formation. The mesenteric region is a weak area, which is a site prone to parastomal hernia, and should be protected.