Omental necrosis masquerading as urinary retention following laparoscopic Roux en Y gastric bypass for super obesity

Omental torsion is a rare cause of an acute abdomen. It often mimics acute appendicitis and other common pathological causes underlying acute abdominal pain. It is defined as axial twisting along its long axis and has primary and secondary classifications. Secondary omental torsion has an underlying aetiology which includes factors that increase intra-abdominal pressure: abdominal hernias, previous abdominal surgery and blunt and penetrating trauma. A common finding is for the central portion to tort due to fixed points above and below. It has a male preponderance (2:1) particularly in the fourth and fifth decades. Symptoms include severe abdominal pain and nausea. Clinical examination often demonstrates localized abdominal tenderness and guarding suggestive of peritonitis. A palpable mass can be present if the omentum is large. Preoperative diagnosis has increased due to high-quality imaging to elucidate a definitive cause of an acute abdomen. However, due to its atypical presentation and clinical similarities to other pathological processes it is often only diagnosed on exploratory laparoscopy. We report a case of secondary omental torsion that was only definitively diagnosed at re-laparoscopy following a laparoscopic Roux en Y gastric bypass.