Partial Stent-in-Stent Method with an Uncovered Self-Expandable Metallic Stent for Unresectable Malignant Hilar Bile Duct Obstruction

(1) Background: There is controversy regarding stent placement for unresectable malignant hilar biliary obstruction (UMHBO). We mainly use the partial stent-in-stent (PSIS) method with an uncovered self-expandable metallic stent (UCSEMS) based on the drainage area and patency period. In this study, we investigated the usefulness and safety of the PSIS method. (2) Methods: In total, 59 patients who underwent the PSIS method for UMHBO at our hospital were included in the study. The technical success rate, clinical success rate, time to recurrent biliary obstruction (TRBO) and overall survival (OS) from the first placement, factors affecting TRBO and OS, and early complications within 30 days after the procedure were evaluated retrospectively. (3) Results: The technical and clinical success rates were 100% and 96.6%, respectively, with a TRBO of 121 days [95% confidence interval: 82–231] and an OS of 194 days [95% confidence interval: 113–305] after the first placement. Early complications occurred in nine patients (15.3%), including five cases of cholangitis, three cases of pancreatitis, and one case of cholecystitis. (4) Conclusions: The PSIS method for UMHBO is safe and useful with high technical and clinical success rates.