Alterations in pancreatic ductal morphology following polyethylene pancreatic stent therapy

Background: Polyethylene stents placed in the main pancreatic duct induce morphologic alterations that may resemble chronic pancreatitis. Methods: We reviewed the sequential pancreatograms of stented patients who had long-term follow-up after stent removal. Results: Forty patients (66%) had a normal baseline pancreatogram, whereas 21 (34%) showed changes of chronic pancreatitis. In 49 of 61 patients (80.3%), one or more had new morphologic changes immediately after stent withdrawal graded as mild (69%), moderate (29%), or severe (2%). Changes included ductal irregularity (49%), narrowing (35.5%), and side branch change(15.5%). Sixteen of the 21 patients (76.1%) with an abnormal baseline pancreatogram had worsening of the baseline abnormality or additional changes while stented, whereas 33 of 40 (82.5%) with a normal baseline developed new morphologic changes. Correlation of stent-induced changes with stent size, length, patency at removal, and duration of stenting failed to show an association. Twenty-five patients with stent-induced changes had a follow-up pancreatogram at a mean of 192 days (10 to 740) after stent removal. There was complete resolution of the changes in 64%, partial resolution in 32%, and no improvement in 5%. Conclusion: Morphologic changes induced by polyethylene pancreatic duct stents occurred in 80% of patients. More than one third of these changes did not resolve during the follow-up period. Because of concern over stent-induced fibrosis, the use of pancreatic stents should remain largely experimental.