CT Scan Reliability in Detecting Internal Hernia after Gastric Bypass.

Background and Objectives: Internal hernia (IH) after gastric bypass can be a life-threatening complication. Obstruction presents acutely or as chronic relapses, with symptoms of abdominal pain, nausea, and vomiting. Early detection and exploration of IH as the cause of small bowel obstruction (SBO) is critical in this surgical emergency and can reduce morbidity and mortality. We conducted a retrospective review of laparoscopic Roux-en-Y bypass (LRYGB) records to determine the specificity and sensitivity of computed tomography (CT) in identifying postoperative IH.

Methods: Records of 550 patients who underwent antecolic antegastric laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery over a 5-year period (2010-2014) were retrospectively reviewed for complications. Our study population comprised patients who returned with signs and symptoms of obstruction who underwent CT imaging followed by laparoscopic exploration.

Results: Thirty-four patients were found to have obstruction on CT scan at ≥6 weeks after LRYGB. Six (17.7%) were found to have IH by preoperative CT imaging before laparoscopic exploration. Of the 6 patients identified to have IH before exploration, 4 (28%) had consistent findings at operation, yielding a sensitivity of 28.6% and specificity of 90.0%. Operative findings identified other causes of SBO: adhesions (n = 17), IH (n = 14), jejunojejunostomy stenosis (n = 2), and phytobezoar (n = 1).

Conclusions: IH after LRYGB is difficult to detect. Our study found CT to have a low sensitivity but a high specificity in detecting IH. Therefore, laparoscopic exploration continues to be the best diagnostic and therapeutic intervention for this complication.