Evaluating safety and efficacy of plastic versus metal stenting in malignant hilar biliary obstruction: a systematic review and meta-analysis of randomized controlled trials

Background: Stenting malignant hilar biliary obstruction (MHBO) is challenging due to its complex structure, and it is less effective than blockages in the distal bile duct area. Plastic stents (PSs) and metal stents (MSs) are commonly used for stenting MHBO. This study aims to compare the outcomes of PSs and MSs in MHBO patients. Methods: We conducted a search of medical databases up to March 2024. Using a fixed-effect model, we analyzed the risk ratios (RRs) of the outcomes between the PS and MS groups. We calculated the RR for clinical and technical success, reinterventions, and adverse events, as well as the hazard ratio (HR) for survival and stent patency. Results: This analysis includes five randomized controlled trials (RCTs) that met the inclusion criteria, comprising a total of 322 patients (156 in the PS group and 166 in the MS group). Significant differences (P < .05) in favor of the MS group were found in the reinterventions (RR 1.80, 95% CI 1.07-3.04), and stent patency (HR 0.54, 95% CI 0.32-0.90). There were no significant differences (P > 0.05) between the PS and MS groups regarding technical success (RR 1.01, 95% CI 0.94-1.09), clinical success (RR 0.86, 95% CI 0.69-1.07), overall survival (HR 0.71, 95% CI 0.47-1.05), stent migration (RR 0.69, 95% CI 0.08-6.02), stent occlusion (RR1.32, 95% CI 0.97-1.81), and adverse events (RR 0.80, 95% CI 0.53-1.20). Conclusion: Both PS and MS are effective for managing MHBO, while MS offers greater efficacy in increased stent patency and lower reintervention rates.