Page 144 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

Chapter 7
Abstract
Introduction
Incisional hernia (IH) can be attributed to multiple factors. The presence of a parastomal hernia has shown to be a risk factor for IH after midline laparotomy. Our hypothesis is that this increased risk of IH might be caused by changes in biomechanical forces, such as midline shift to the contralateral side of the colostomy owing to decreased restraining forces at the site of the colostomy, and left abdominal rectus muscle (ARM) atrophy owing to intercostal nerve damage.
Methods
Patients were selected if they underwent an end-colostomy via open operation between 2004 and 2011. Patients were eligible if computed tomography (CT) had been performed postoperatively. If available, pre-operative CT-scans were collected for case-control analyses. Midline shift was measured using V-Scope application in I-Space®, a CAVETM-like virtual reality system. For the ARM atrophy hypothesis, measurements of ARM were performed at, the level of colostomy, and 3cm and 8 cm cranial and caudal of the colostomy.
Results
Postoperative CT-scans were available for 77 patients; of these patients, 30 also had received a preoperative CT-scan. Median follow-up was 19 months. A mean shift to the right side was identi ed after preoperative and postoperative comparison; from -1.3 +/- 4.6 to 2.1 +/-9.3(p = 0.043). Furthermore, during rectus muscle measurements, a thinner left abdominal rectus muscle was observed below the level of colostomy.
Discussion
Creation of a colostomy alters the abdominal wall. Atrophy of the left ARM was seen caudal to the level of the colostomy, and a midline shift to the right side was evident on CT-scan. These changes may explain the increased rate of IH after colostomy creation.
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