Internal hernia due to gastric bypass surgery

Last revised by Liz Silverstone on 9 Jul 2023

Internal hernias due to gastric bypass surgery are more common after laparoscopic gastric bypass than after an open procedure. 

Incidence after a Roux-en-Y gastric bypass may range between 1-16%. The presence of strangulation may be associated with a mortality rate exceeding 50% ref.  

It is a particularly sinister complication with variable, non-specific clinical presentations. Most patients report a combination of postprandial abdominal pain, nausea and emesis 1. Patients may present at any time after surgery, however the majority are delayed, occurring after more than a month 2.

Physical examination findings are likewise non-specific, and may range from vague abdominal tenderness to palpation to peritonism ref

It has been suggested that patients are more prone to internal hernias after laparoscopic Roux-en-Y gastric bypass than after an open operation because there are fewer adhesions to tether small-bowel loops and prevent them from herniating. In addition, patients who have greater degrees of weight loss after laparoscopic Roux-en-Y gastric bypass may be more prone to internal hernia because of loss of the protective, space-occupying effect of mesenteric fat 1

Laparoscopic Roux-en-Y gastric bypass surgery produces three potential sites for internal hernia formation: 

  • at the defect in the transverse mesocolon through which the Roux limb passes (if it is placed in the retrocolic position)
  • at the mesenteric defect at the enteroenterostomy
  • behind the Roux limb mesentery placed in a retrocolic or antecolic position (retrocolic Petersen and antecolic Petersen type) 1

Postoperative complications which may present similarly after re-routing procedures include:

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