IBC Oxford University Poster Abstract 23 - Incidence and predictors of petersen’s hernia after laparoscopic antecolic Roux-en-Y gastric bypass—5 year results of an experienced center

Abstract Background Roux-en-Y gastric bypass (RYGB) is the second most frequent bariatric procedure worldwide. Internal herniation is a well-described late complication of this operation. Petersen’s hernia (PH) occurs within Petersen’s space, which is iatrogenically created between the transverse mesocolon, the Roux limb, and the retroperitoneum. The aims of this study were to investigate the incidence of symptomatic Petersen’s hernias (PH), to determine risk factors for their occurrence, and provide insight on the eventual benefit of systematic Petersen’s space closure in addition to mesenteric defect closure. Methods A single-centre retrospective descriptive study was performed. Patients submitted to laparoscopic RYGB from January 2019 to December 2023 in our centre were included. All patients were reconstructed in an antecolic anastomosis fashion. Only cases of symptomatic PH were eligible. Results During a 5-year period, 2117 patients were submitted to laparoscopic RYGB without routine closure of Petersen’s space. Exploratory laparoscopy for suspicion of bowel obstruction and consecutive Petersen’s space closure with running non-absorbable suture was performed in 22 patients. Mean age of PH patients was 43.6 (±10.3) years. Regarding gender, twenty patients (90.9%) were female. In our study’s timeframe 9 patients had BGYR and consequently PH surgery leading to a 0.4% incidence. In this same period, 13 other patients who underwent RYGB prior to 2019 (7), or in another institution (6), were also operated for PH. The median time between RGYB and PH surgery was 28.1 months (IQR 42.7). Mean preoperative BMI at PH surgery was lower than mean 24 months’ post-RYGB BMI for non-PH patients (24.7 ± 4.0 versus 26.9 ± 4.0, P = 0.011). Revisional surgery and gastric remnant resection were not risk factors for PH (P = 0.185 and P = 0.988, respectively). We report no cases of bowel necrosis or mortality. No PH recurrences were recorded. Conclusions PH is a potentially serious complication of RGYB. Its clinical presentation ranges widely, from asymptomatic to mild and intermittent abdominal cramping and colicky pain to acute small bowel obstruction and ultimately intestinal strangulation. CT scan is helpful preoperatively and careful attention should be given to indicators of midgut volvulus such as the mesenteric swirl sign. PH must be suspected in RGYB patients even if their symptoms are scarce.