The burden of abdominal pain after bariatric surgery in terms of diagnostic testing: the OPERATE study

Background: Abdominal pain after bariatric surgery (BS) is frequently observed. Despite numerous diagnostic tests, the cause of abdominal pain is not always found. Objectives: To quantify type and number of diagnostic tests performed in patients with abdominal pain after BS and evaluate the burden and their yield in the diagnostic process. Setting: A bariatric center in the Netherlands. Methods: In this prospective study, we included patients who presented with abdominal pain after BS between December 1, 2020, and December 1, 2021. All diagnostic tests and reoperations performed during one episode of abdominal pain were scored using a standardized protocol. Results: A total of 441 patients were included; 401 (90.9%) were female, median time after BS was 37.0 months (IQR, 11.0–66.0) and mean percentage total weight loss was 31.41 (SD, 10.53). In total, 715 diagnostic tests were performed, of which 355 were abdominal CT scans, 155 were ultrasounds, and 106 were gastroscopies. These tests yielded a possible explanation for the pain in 40.2% of CT scans, 45.3% of ultrasounds, and 34.7% of gastroscopies. The diagnoses of internal herniation, ileus, and nephrolithiasis generally required only 1 diagnostic test, whereas patients with anterior cutaneous nerve entrapment syndrome, irritable bowel syndrome, and constipation required several tests before diagnosis. Even after several negative tests, a diagnosis was still found in the subsequent test: 86.7% of patients with 5 or more tests had a definitive diagnoses. Reoperations were performed in 37.2% of patients. Conclusion: The diagnostic burden in patients with abdominal pain following BS is high. The most frequently performed diagnostic test is an abdominal CT scan, yielding the highest number of diagnoses in these patients.