Incidence and risk factors for biliary and pancreatic stent migration.

Endoprostheses are commonly used in the treatment of biliary and pancreatic disorders. The frequency of and potential risk factors for stent migration, however, remain largely unknown. From January 1986 to June 1990, 807 biliary and pancreatic stents were placed at our institution. Our study analyzed the occurrence of stent migration among the 589 stents for which follow-up data were available. Results demonstrated incidence rates of 4.9 and 5.9% for proximal (into the duct) and distal (out of the duct) biliary stent migration, respectively. Likewise, incidence rates of 5.2 and 7.5% were observed for proximal and distal pancreatic stent migration, respectively. Malignant strictures, larger diameter stents, and shorter stents were significantly associated with proximal biliary stent migration. Sphincter of Oddi dysfunction and longer stents were associated with proximal pancreatic stent migration. Migration of stents out of the common bile duct occurred more frequently in papillary stenosis. No other significant risk factors for distal migration were found. These results indicate that stent migration is an important complication. Multiple risk factors were associated with stent migration and need to be considered in the development of new stent types.