Assessing spontaneous passage of prophylactic pancreatic duct stents by X-ray: is a radiology report adequate?

Background: Pancreatic duct stents are frequently placed for prophylaxis of post-endoscopic retrograde cholangiopancreatography pancreatitis. Because of concern for possible secondary ductal changes from a retained stent, these stents need to be monitored and removed if retained. Usually an abdominal X-ray is performed to assess retained stent, and if present, an esophagogastroduodenoscopy is performed to remove the stent. Limited data is published on false-negative radiology reports for spontaneous passage of stents. Methods: Using an Institutional Review Board–approved stent log, a retrospective chart review of all pancreatic duct stents placed at our institution from 2008 to 2014 was performed. Results: A total of 856 pancreatic duct stents were placed during the study period. Of these, 435 (50.8%) were prophylactic stents and 421 (49.2%) were therapeutic. Complete follow-up data were available in 426 (97.9%) patients with prophylactic stents. Six patients (1.4%) were lost to follow up and three (0.7%) expired prior to removal. In all, 283 (66%) had follow-up imaging, with 167 (39.2%) having the official radiology read with no retained pancreatic duct stent in place. Eight of these cases were “false-negative” radiology interpretation (4.8% of cases read as “no stent,” NNH = 20). The stent was found either by review of image by an endoscopist or incidental stent discovery during a follow-up procedure. Conclusion: Radiologist interpretation of abdominal X-rays to assess spontaneous passage of prophylactic pancreatic ducts stents resulted in a false-negative interpretation in approximately 5% of cases. Independent review of the images by the endoscopist may be beneficial given unfamiliarity of these stents by radiologists.