title: Rapid excess weight loss following laparoscopic gastric bypass leads to increased risk of internal hernia.
abstract: BACKGROUND
  Internal hernia (IH) is one of the more acute and potentially devastating complications after laparoscopic gastric bypass (LGB). Currently, there is no way to predict which patients will develop IH. We propose that patients who undergo periods of rapid excess weight loss (EWL) following LGB are more likely to develop IH.
  
  
  METHODS
  A retrospective review of a prospectively collected laparoscopic gastric bypass database from our bariatric center was performed. Patient data between 2002 and 2009 was reviewed. Demographics, initial body mass index (BMI), detailed weight loss curves, and morbidity, specifically IH, were reviewed. Statistical analysis was performed. Logistic regression analysis was used to obtain an adjusted odds ratio for rapid weight loss and hernia development.
  
  
  RESULTS
  We reviewed all 934 LGB procedures performed. The average initial BMI was 49.1 kg/m2 (range=34-91 kg/m2). EWL based on our current averages at 1, 3, 6, 9, and 12 months postoperatively were 20, 40, 60, 75, and 85%. We statistically defined rapid EWL as greater than the 90th percentile for weight loss. Rapid EWL was noted in 33.2% (310/934) of patients. Fifty-eight (6.2%) patients were identified with IH. Of these, 27(46.5%) had periods of rapid EWL (odds ratio [OR]=1.83; 95% CI=1.07, 3.02). Bivariate analysis of patient factors that led to rapid EWL identified initial BMI (49.3 vs. 46.6 kg/m2) and rapid EWL as increasing the likelihood of developing IH (p=0.026). A multivariate logistic model for IH identified only rapid EWL as a predictive factor. Locations of IH were the jejunojejunostomy (24), Pedersen's defect (23), adhesions (9), and colonic mesentery (1). There were five patients with combined JJ and Pederson's hernias.
  
  
  CONCLUSIONS
  Outcomes from missed IH can be catastrophic. In our large, single-center series, we have found that patients who undergo periods of rapid EWL are at nearly twice the risk for development of IH as the rest of the gastric bypass population.
authors.affiliation: Department of Surgery, Greenville Hospital System University Medical Center, Greenville, SC 29605-4281, USA. Schneidercr1@hotmail.com
authors.forename: Christopher
authors.initials: C
authors.lastname: Schneider
authors.forename: William
authors.initials: W
authors.lastname: Cobb
authors.forename: John
authors.initials: J
authors.lastname: Scott
authors.forename: Alfredo
authors.initials: A
authors.lastname: Carbonell
authors.forename: Katie
authors.initials: K
authors.lastname: Myers
authors.forename: Eric
authors.initials: E
authors.lastname: Bour
mesh_terms: D000328:Adult; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects; D046449:Hernia, Abdominal / Q000209:etiology*; D006801:Humans; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000601:surgery*; D012307:Risk Factors; D015431:Weight Loss