Internal Herniation and Weight Loss in Patients after Roux-en-Y Gastric Bypass

Purpose Weight loss is one of the desired outcomes after a gastric bypass, in order to reduce co-morbidity, and even mortality. However, weight loss might contribute to a serious complication: internal herniation (IH). Pre-operative diagnosis of IH is demanding. This study was conducted to investigate if percentage total weight loss (%TWL) is clinically usable in recognizing patients with IH. Materials and Methods Patients who had undergone a gastric bypass between 2011 and 2014 were included retrospectively if a CT scan or reoperation was performed for suspected IH between 2011 and 2016. Differences in %TWL were calculated in patients with IH and without (NO-IH). A sub analysis was done in patients with complaints. A multivariate analysis to identify risk factors for IH was performed. Results Out of 1007 patients, 31 patients were diagnosed with an IH (3.1%) after a median time of 16.5 months (range 6.5-46.1). The %TWL was higher in patients with an IH (34.2% +/- 12.7) vs. NO-IH (30.8% +/- 9.6). This result was also seen in patients presenting with symptoms (IH 34.2% +/- 12.7 vs. NO-IH 27.0% +/- 14.8). If %TWL is above 30%, IH is significantly more diagnosed in patients presenting with symptoms. A multivariate logistic model for IH in patients presenting with symptoms identified both >= 30%TWL (adjusted OR 3.1, 95% CI 1.1-8.8, p = 0.036) and abdominal cramping (adjusted OR 3.2, 95% CI 1.2-8.5, p = 0.0021) as risk factors. Conclusion Our study showed significant more %TWL in patients with an IH. Both >= 30%TWL and cramping abdominal pain result in a threefold higher risk of presence of IH.