title: The four different types of internal hernia occurring after laparascopic Roux-en-Y gastric bypass performed for morbid obesity: are there any multidetector computed tomography (MDCT) features permitting their distinction?
abstract: BACKGROUND
  Four different types of internal hernias (IH) are known to occur after laparoscopic Roux-en-Y gastric bypass (LRYGBP) performed for morbid obesity. We evaluate multidetector row helical computed tomography (MDCT) features for their differentiation.
  
  
  METHODS
  From a prospectively collected database including 349 patients with LRYGBP, 34 acutely symptomatic patients (28 women, mean age 32.6), operated on for IH immediately after undergoing MDCT, were selected. Surgery confirmed 4 (11.6%) patients with transmesocolic, 10 (29.4%) with Petersen's, 15 (44.2%) with mesojejunal, and 5 (14.8%) with jejunojejunal IH. In consensus, 2 radiologists analyzed 13 MDCT features to distinguish the four types of IH. Statistical significance was calculated (p<0.05, Fisher's exact test, chi-square test).
  
  
  RESULTS
  MDCT features of small bowel obstruction (SBO) (n=25, 73.5%), volvulus (n=22, 64.7%), or a cluster of small bowel loops (SBL) (n=27, 79.4%) were inconsistently present and overlapped between the four IH. The following features allowed for IH differentiation: left upper quadrant clustered small bowel loops (p<0.0001) and a mesocolic hernial orifice (p=0.0003) suggested transmesocolic IH. SBL abutting onto the left abdominal wall (p=0.0021) and left abdominal shift of the superior mesenteric vessels (SMV) (p=0.0045) suggested Petersen's hernia. The SMV predominantly shifted towards the right anterior abdominal wall in mesojejunal hernia (p=0.0033). Location of the hernial orifice near the distal anastomosis (p=0.0431) and jejunojejunal suture widening (p=0.0005) indicated jejunojejunal hernia.
  
  
  CONCLUSIONS
  None of the four IH seems associated with a higher risk of SBO. Certain MDCT features, such as the position of clustered SBL and hernial orifice, help distinguish between the four IH and may permit straightforward surgery.
authors.affiliation: Department of Radiology, University Hospital-CHUV, 1011, Lausanne, Switzerland.
authors.forename: Aida
authors.initials: A
authors.lastname: Kawkabani Marchini
authors.forename: Alban
authors.initials: A
authors.lastname: Denys
authors.forename: Alexandre
authors.initials: A
authors.lastname: Paroz
authors.forename: Sébastien
authors.initials: S
authors.lastname: Romy
authors.forename: Michel
authors.initials: M
authors.lastname: Suter
authors.forename: Nicolas
authors.initials: N
authors.lastname: Desmartines
authors.forename: Reto
authors.initials: R
authors.lastname: Meuli
authors.forename: Sabine
authors.initials: S
authors.lastname: Schmidt
mesh_terms: D000328:Adult; D005260:Female; D015390:Gastric Bypass; D006547:Hernia / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D007415:Intestinal Obstruction / Q000000981:diagnostic imaging / Q000209:etiology; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000209:etiology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed