Clinical characteristics and risk factors for stent–stone complex formation following biliary plastic stent placement in patients with common bile duct stones

Background Stent–stone complex (SSC) formation is one of the complications of endoscopic biliary stent placement. This study aimed to clarify the clinical characteristics and risk factors for SSC formation following plastic stent (PS) placement in patients with common bile duct (CBD) stones. Methods We retrospectively reviewed the charts of 78 patients with CBD stones who had undergone 107 biliary stent placements as palliative treatment. Demographic, historical, and stent‐related data were collected and analyzed. Results At PS removal, SSC formations were observed in 18% of the 107 cases (SSC group) studied and not in the remaining 82% (non‐SSC group). The duration of PS placement was significantly longer in the SSC group. The increase in CBD diameter during the stenting period as well as the incidence of cholangitis at PS removal was significantly greater in the SSC group. Multivariate analysis identified long‐term (≥301 days) PS placement and the increase in CBD diameter during the stenting period as independent factors for SSC formation. Conclusions Long‐term PS placement induces a risk of SSC formation in patients with CBD stones. The increase in diameter of CBD during the period of PS placement is a predictive factor for SSC formation in this situation. Highlight Kaneko and colleagues conducted the first retrospective study investigating stent‐stone complex formation following plastic stent placement in patients with common bile duct stones. Long‐term stenting was a crucial risk factor and increase in the common bile duct diameter during the stenting period was a predictive factor for stent‐stone complex formation.