title: Abdominal rectus muscle atrophy and midline shift after colostomy creation.
abstract: BACKGROUND
  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 may 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 end-colostomy via open operation between 2004 and 2011. Patients were eligible if computed tomography (CT) had been performed postoperatively. If available, preoperative CTs were collected for case-control analyses. Midline shift was measured using V-scope application in the I-space, a CAVE-like virtual reality system. For the ARM atrophy hypothesis, measurements of ARM were performed at the level of colostomy, and 3 and 8 cm cranial and caudal of the colostomy.
  
  
  RESULTS
  Postoperative CT were available for 77 patients; of these patients, 30 also had a preoperative CT. Median follow-up was 19 months. A mean shift to the right side was identified after preoperative and postoperative comparison; from -1.3 ± 4.6 to 2.1 ± 9.3 (P = .043). Furthermore, during rectus muscle measurements, a thinner left ARM was observed below the level of colostomy.
  
  
  CONCLUSIONS
  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. These changes may explain the increased rate of IH after colostomy creation.
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands. Electronic address: l.timmermans@erasmusmc.nl.
authors.forename: Lucas
authors.initials: L
authors.lastname: Timmermans
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Eva B
authors.initials: EB
authors.lastname: Deerenberg
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Sven M
authors.initials: SM
authors.lastname: van Dijk
authors.affiliation: Department of Surgery, Albert Schweitzer Hospital, Dordrecht, The Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: Lamme
authors.affiliation: Department of Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Anton H
authors.initials: AH
authors.lastname: Koning
authors.affiliation: Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: Kleinrensink
authors.affiliation: Department of Neuroscience, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Johannes
authors.initials: J
authors.lastname: Jeekel
authors.affiliation: Department of Surgery, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Johan F
authors.initials: JF
authors.lastname: Lange
mesh_terms: D000009:Abdominal Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015331:Cohort Studies; D003125:Colostomy / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D046449:Hernia, Abdominal / Q000453:epidemiology; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D009426:Netherlands; D012007:Rectum / Q000000981:diagnostic imaging / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed