Postoperative ERCP as proxy for clinically significant retained stones in a population-based cohort?

Background: The rate of retained common bile duct stones (CBDS) following cholecystectomy can only be estimated if CBDS managed conservatively as well as CBDS treated with endoscopic retrograde cholangiopancreatography (ERCP) are identified. The aim was to explore the rate of retained CBDS and evaluate performance of ERCP as proxy for retained CBDS in a population-based setting. Methods: Data were collected from The Swedish Gallstone Surgery and Endoscopic Retrograde Cholangiopancreatography Register (GallRiks) on patients who underwent cholecystectomy 2015-2020 with suspected CBDS at South General Hospital, Stockholm, Sweden. Medical records were reviewed to identify rate of patients with events raising suspicion of passage of retained CBDS and compare this to the rate of ERCP for retained CBDS. Results: A total of 182 of 386 patients (47.2%) had CBDS on intraoperative cholangiography (IOC). During follow-up, 33 of the 182 presented with retained CBDS according to medical records. Of these, 24 had an ERCP registered in GallRiks with retained CBDS reported, whereas 9 had retained CBDS according to medical records only. Conclusion: Postoperative ERCP found valid as proxy for retained stones following surgery for CBDS and can be a quality measure for management of patients undergoing gallstone surgery with suspicion of CBDS.