Self-expandable metal stents have longer patency and less cholangitis than inside stents in malignant perihilar biliary obstruction

Background and Aim: Outcomes of an inside stent (IS, a plastic stent placed above the sphincter of Oddi) versusa self-expandable metal stent (SEMS) for the drainage of malignant perihilar biliary obstruction has not been fully studied. The drainage strategy for perihilar biliary obstruction is difficult and should be clarified. Methods: Clinical data of patients who underwent biliary drainage for malignant perihilar biliary obstruction with IS or SEMS between April 2016 and September 2021 at our institution were retrospectively examined. Outcomes, including the time to recurrent biliary obstruction (TRBO), survival, and incidence of recurrent biliary obstruction with concomitant cholangitis (RBOC), were retrospectively evaluated. Results: Median TRBO was 280 (95% confidence interval [CI], 110-not available) days in the SEMS group (n = 24) and 113 (95% CI, 74-192) days in the IS group (n = 25) (P = 0.043). Among the patients with perihilar cholangiocarcinoma, the median survival of the two groups was comparable, namely 330 days in the SEMS group and 359 days in the IS group (P = 0.46). The incidence of RBOC at reintervention was significantly higher in patients with ISs (83.9%) than in those with SEMSs (0%) (P = 0.00004). Conclusions: TRBO was significantly longer in the SEMS group. Regardless of whether SEMSs or ISs were placed during the first intervention, patient survival was similar. Using easily removable ISs first might be a reasonable option because TRBO with SEMSs was shorter than patient survival. Cholangitis is a problem associated with the placement of IS.