Journal Review in Bariatric Surgery: Mesenteric Defect Closure and Internal Hernia Evaluation/Management

To close or not to close - that is the question!  Internal hernias following bariatric surgery can be a vexing source of delayed postoperative morbidity.  Join Drs. Matthew Martin, Kunoor Jain-Spangler, Adrian Dan, and Vincent Cheng for this EXCELLENT Journal Review in Bariatric Surgery.  

Article #1: Stenberg 2023 - Long-term Safety and Efficacy of Closure of Mesenteric Defects in Laparoscopic Gastric Bypass Surgery

• Two mesenteric defects are created during Roux-en-Y gastric bypass (RNYGB)
  • Petersen’s Defect
  • Jejuno-jejunostomy mesenteric defect
•  Consensus does not exist regarding the standard of care for mesenteric defect closure (e.g., closure of one or both defects, material used for closure).  
  • Risks of leaving defects open: internal herniation with or without bowel ischemia
•  Risks of closing defects
  • Kinking the bowel (especially near the jejunojejunostomy) leading to obstruction 
  • Chronic abdominal pain
• This article discusses a randomized controlled trial of obese patients undergoing bariatric RNYGB
  • Randomized into two groups: a closure group and a non-closure group 
  • Followed patients for 10 years with 95-96% follow up rate
  • Results analyzed using a Cox proportional hazards regression that included risk factors like BMI, total weight loss at 1 year after surgery, and the other 
  • Highlighted outcomes
    •  Within the first 30 postop days, there was a higher rate of SBO in the closure group (1.3%) compared to the non-closure group (0.2%). This was attributed to kinking of the jejunojejunostomy
    •  After 30 postop days and up to 10 years, reoperation rates for SBO were higher in the non-closure group (14.9%) compared to the closure group (7.8%). This trend was consistent regarding each site of mesenteric defect. 
    • No significant differences between the two groups regarding chronic opioid use as a metric of chronic abdominal pain.

Article #2: Nawas 2022 - The Diagnostic Accuracy of Abdominal Computed Tomography in Diagnosing Internal Herniation Following Roux-en-Y Gastric Bypass Surgery

• Unless there is an indication to immediately operate on a RNYGB patient in whom internal herniation is suspected, computed tomography (CT) is the recommended diagnostic test
• This article is a meta-analysis of 20 studies published between 2007 and 2020 that analyzed the accuracy of CT or detecting internal hernias in adult patients who underwent RNYGB for morbid obesity. A collective total of 1,637 patients were included.  
• Accuracy was determined by comparing diagnostic CT with exploratory surgery or the combination of negative CT and a negative 90 days follow-up
• Internal herniation was defined as presence of herniated small bowel with or without obstruction or ischemia through a visible opening at the mesenteric defect
• Results
  • Pooled sensitivity of CT was 82% and specificity was 85%
  • Positive predictive value of CT was 83% and negative predictive value was 86%
• CT signs with the highest sensitivity (sensitivity of finding) 
  • Venous congestion (79%)
  • Swirl sign (78%) 
  • Mesenteric edema (67%)
• 15% risk of an internal hernia even with a negative CT scan 
  • In conclusion, CT can provide useful information, but these are just additional data points to consider in the overall evaluation of a patient. Surgeons should still have a low threshold for diagnostic laparoscopy even with negative CT findings

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