Role of CT imaging in discriminating internal hernia from aspecific abdominal pain following Roux-en-Y gastric bypass: a single high-volume centre experience

Internal hernia (IH) represents a delayed complication of the laparoscopic Roux-en-Y gastric bypass (LRYGB) and it is historically difficult to identify preoperatively. Numerous CT signs were considered suggestive of IH but none of them is pathognomonic. In this study, we aim to evaluate the accuracy of CT in diagnosing IH, differentiating from non-specific abdominal pain. This can lead to a way of personalized medicine and improve the outcome of anti-obesity treatments. We retrospectively reviewed CT scans of 50 patients previously subjected to LRYGB procedure, with a clinical suspicion of IH. 3 groups of patients were identified: IH group (21 patients with a surgical confirmed IH), negative group (12 patients in whom IH was not confirmed at surgery), and control group (17 patients who were not surgically explored because of low/no suspicion of IH). We divided CT signs into three groups: "bowel loop signs", "vessel signs", and "venous congestion/stasis signs". The accuracy of CT in detecting IH was tested by comparing each sign, either individually or in combination, with the surgical findings. Statistical analysis showed that "vessel signs" (swirl sign, superior mesenteric vein beaking, mesenteric arteries, and veins branches inversion) present the highest distribution in patients with IH demonstrated at surgery, with a higher accuracy in case of simultaneous presence of two or three signs. CT imaging is highly accurate in diagnosing IH. Despite no single sign being pathognomonic, the combination of two or more signs, especially among the "vessels signs", can suggest the IH, even in pauci-symptomatic patients.