Mesenteric Defect Closure Decreases the Incidence of Internal Hernias Following Laparoscopic Roux-En-Y Gastric Bypass: a Retrospective Cohort Study.

Background: Laparoscopic Roux-en-Y gastric bypass (LRYGB) is one of the most effective bariatric procedures. Internal hernia (IH) is the commonest long-term complication seen after LRYGB. We analyzed the impact of closure of mesenteric defect at primary surgery on the incidence of IH. We also studied the effectiveness of pre-operative abdominal contrast-enhanced computerized tomography (CECT) in diagnosing IH.

Methods: This is a retrospective cohort study in which we analyzed prospectively the collected data of all patients who underwent LRYGB from 2005 to 2014. All patients post-LRYGB presenting with unexplained abdominal pain with a suspicion of IH were subjected to a CECT abdomen, in which we looked specifically for "whirlpool" sign and "clustering of bowel loops." All patients underwent diagnostic laparoscopy. We compared the incidence of IH in those who did not undergo mesenteric defect closure (2005-2008, i.e., group A) with those who had the mesenteric defects closed during primary surgery (2009-2014, i.e., group B). We also calculated the sensitivity of abdominal CECT in diagnosing IH pre-operatively.

Results: Among patients who did not undergo closure of any mesenteric defect (group A 2005-2009), 21/600 (3.5 %) developed IH, while 17/976 (1.7 %) patients who underwent mesenteric defect closure (group B 2009-2014) developed IH (p = 0.027). Pre-operative CECT abdomen confirmed the diagnosis of IH in 47.5 % (19/40 patients).

Conclusions: Closing of mesenteric defects after laparoscopic gastric bypass seems to be related to a lower incidence of internal hernia in the follow up. As the sensitivity of abdominal CECT is low, laparoscopic exploration is recommended based on clinical suspicion.