Compression of the superior mesenteric vein-a sign of acute internal herniation in patients with antecolic laparoscopic Roux-en-Y gastric bypass.

OBJECTIVES

To investigate whether compression of the superior mesenteric vein (SMV) on computed tomography (CT) can serve as a valid sign of internal herniation (IH) in patients with antecolic laparoscopic Roux-en-Y gastric bypass (LRYGBP).

MATERIALS AND METHODS

With institutional review board approval, we performed a retrospective analysis of 41 patients with antecolic LRYGBP referred for acute CT of the abdomen with suspicion of IH or another cause of acute abdomen. CT scans were randomly reviewed for signs of IH by two radiologists in a blinded manner, and the findings were correlated with the results of the patients' bariatric workup. Sensitivity, specificity, and inter-observer agreement were calculated for each sign.

RESULTS

Five patients were classified as having intermittent IH and were excluded. Eighteen patients were found to have IH at laparoscopy and served as the study group; 18 patients served as the control group. SMV compression had the best sensitivity (67 % for both reviewers) and inter-observer agreement (kappa = 0.82) of all investigated signs. The swirl sign showed a lower sensitivity (39 and 50 % respectively) and kappa (0.37).

CONCLUSION

SMV compression is a reliable sign of IH in patients with antecolic LRYGBP.

KEY POINTS

• CT can help detect internal herniation after laparoscopic Roux-en-Y gastric bypass. • Compression of the superior mesenteric vein is a sign of internal herniation. • This sign has a high inter-observer-agreement. • A diagnosis of internal herniation can be made with greater confidence.