Migration of biliary plastic stents: experience of a tertiary center

Stent migration occurs in about 5-10% of patients undergoing biliary stenting. The aim of this study was to analyze the risk factors for stent migration in patients with benign and malignant strictures. We retrospectively analyzed records of 524 biliary plastic stent placement procedures. Details noted included the cause and localization of stricture, characteristics and number of stents, direction of stent migration, presentation of patient with migrated stent, and the methods used for retrieval of migrated stents. Two hundred and four (38.9%) of the procedures were performed for benign biliary strictures (BBS) and 320 (61.1%) for malignant biliary strictures (MBS). Thirty-four patients had 45 migrated biliary stents. The rate of migration was 8.58% (proximal 4.58% and distal 4.00%). Migration frequency was higher in BBS compared with MBS (13.7% versus 5.3%, p = 0.001). In BBS, the rate of stent migration was higher in cases with one (19.3%) and two stents (20.9%) when compared with cases with multiple stents (2.7%) (p = 0.001; p = 0.001, respectively). Migration occurred more frequently (10.9%) in cases with two stents when compared both to cases with one stent (3.0%) and those with multiple stents (0%) in MBS (p = 0.008; p = 0.020, respectively). In BBS, short stents migrated more frequently proximally (77%) and long stents more frequently distally (73%) (p = 0.008). In BBS, migration in cases with proximal stricture occurred more frequently distally (76.9%), while in those with distal stricture, migration was more frequently proximal (73.3%) (p = 0.008). All of the proximally migrated stents could be successfully retrieved endoscopically. The risk of stent migration is higher in BBS compared with in MBS. The cases with multiple stents had significantly lower stent migration. In BBS, long stent, proximal and postcholecystectomy strictures were associated with distal migration, while short stent, distal and non-postcholecystectomy strictures were associated with proximal migration.