Metallic versus plastic stents for the management of biliary obstruction

Background: Biliary obstruction can be managed with metallic stents (MS) or plastic stents (PS), but comparative evidence across benign and malignant conditions remains uncertain. We conducted a systematic review and meta-analysis comparing MS and PS. Methods: PubMed, Embase, Scopus, Web of Science, and Cochrane CENTRAL were searched from inception to the search date. Randomized controlled trials and observational studies comparing MS with PS in patients with benign or malignant biliary obstruction were eligible. Primary analyses compared MS with PS across the overall eligible population, including both benign and malignant obstruction. Where sufficient outcome-specific data were available, subgroup analyses were performed according to disease etiology (benign vs malignant). Outcomes included functional success, adverse events, recurrent biliary obstruction (RBO), procedure time, and overall survival. Meta-analysis was performed with Hartung–Knapp sensitivity analyses. Results: Nine studies comprising 890 participants were included. Functional success was comparable between MS and PS (RR = 1.03, 95% confidence intervals [CI]: 0.96–1.11). Among 8 studies contributing adverse-event data, no significant difference was observed (RR = 1.37, 95% CI: 0.92–2.03; P = .123; I 2 = 45.4%). Adverse events were higher with MS in malignant disease (RR = 1.74, 95% CI: 1.15–2.63) but not benign disease (RR = 1.01, 95% CI: 0.83–1.23; P for subgroup difference = .020). Hartung–Knapp analysis remained non-significant (RR = 1.37, 95% CI: 0.96–1.95; P = .078). MS showed a lower risk of RBO (RR = 0.61, 95% CI: 0.32–1.17; I 2 = 93.1%), supported by Hartung–Knapp analysis (RR = 0.61, 95% CI: 0.41–0.91). Conclusion: MS and PS demonstrated comparable functional success and overall adverse-event rates, although adverse events were higher with MS in malignant disease. MS may improve stent durability, but substantial heterogeneity limits certainty. Available studies did not demonstrate a consistent survival advantage. Further randomized trials are warranted.