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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