Internal hernia after laparoscopic Roux-en-Y gastric bypass: a correlation between radiological and operative findings.

Background: Even though internal hernia (IH) after a laparoscopic Roux-en-Y gastric bypass (LRYGB) is a well-known entity for bariatric surgeons and radiologists, accurate diagnosis remains difficult. The aim of this study was to evaluate the sensitivity and specificity of ten different CT findings in patients with a proven internal hernia after a LRYGB.

Methods: A retrospective analysis of all LRYGB patients who underwent an explorative laparoscopy for abdominal pain has been performed. Preoperative CT scans were individually reviewed by two radiologists specialized in abdominal CT imaging in a randomized blind way. These results were compared with the operative reports.

Results: Between 2004 and 2013, 7,328 patients underwent a LRYGB. One hundred sixty nine of these patients underwent an explorative laparoscopy for abdominal pain after a LRYGB, 131 of which had a preoperative CT scan. Of these 131 patients, 72 suffered from an IH. Fifty-nine patients had no IH and served as control group. Mesenteric swirl was the best predictor with for reader 1 a sensitivity of 68% and specificity of 86% and for reader 2 a sensitivity of 89% and specificity of 63%. Other signs had an even larger interobserver variability.

Conclusions: A CT scan can help in confirming the diagnosis of an IH, especially if a mesenteric swirl is present. However, since the presented sensitivities are variable and do not reach 100%, IH might be missed, implicating that a high index of suspicion with a low threshold for explorative laparoscopy/-tomy remains the cornerstone of appropriate treatment.