Internal hernia due to gastric bypass surgery
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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:
- anastomotic (staple line) leak
- marginal ulceration
- postoperative adhesions with obstruction
- less common cause of small bowel obstruction in this population 3
- 1. Lockhart ME, Tessler FN, Canon CL et-al. Internal hernia after gastric bypass: sensitivity and specificity of seven CT signs with surgical correlation and controls. AJR Am J Roentgenol. 2007;188 (3): 745-50. doi:10.2214/AJR.06.0541 - Pubmed citation
- 2. Altieri M, Altieri WB, Altieri PA, Altieri PA, Altieri. Common weight loss procedures and their complications. (2018) The American journal of emergency medicine. doi:10.1016/j.ajem.2017.11.050 - Pubmed
- 3. Christopher D. Scheirey, Francis J. Scholz, Paresh C. Shah, David M. Brams, Brian B. Wong, Michael Pedrosa. Radiology of the Laparoscopic Roux-en-Y Gastric Bypass Procedure: Conceptualization and Precise Interpretation of Results1. (2006) RadioGraphics. doi:10.1148/rg.265055123