Stenting of the malignant hilar biliary obstruction (MHBO) area for bile drainage is challenging. Bilateral stenting techniques of stent-in-stent (SIS) and stent-by-stent (SBS) have shown promising results. This study evaluates the efficacy of different stenting methods for MHBO.

A meta-analysis was performed to determine the efficacy of SIS and SBS stenting strategies for MHBO.

Medical databases such as PubMed, Web of Science, Embase, and Scopus, were searched up to August 2023. We selected eligible studies reporting the data on technical and clinical success, adverse events, and incidence of re-obstruction (RO) of SBS and SIS groups in MHBO patients. We compared the outcomes of SBS and SIS groups.

A total of 9 studies comparing the data of 545 patients (268 in the SBS group and 277 in the SIS stenting group) were analyzed. There was no significant difference (p > 0.05) in the odds ratio (OR) of Re-obstruction (RO) 0.87 (95% confidence interval (95% CI) 0.6-1.25), technical success 0.58 (95% CI 0.16-2.11), clinical success 1.13 (95% CI 0.62-2.07), and adverse events 1.53 (95% CI 0.88-2.64). The mean difference in procedure time was -12.25 min (95% CI -18.39, -6.12), and the hazard ratio of stent patency was 1.22 (95% CI 1.01-1.47), favoring SBS, with high heterogeneity (I 2 = 94%). There was no significant difference in HR for survival 1.05 (95% CI 0.95-1.16) with high heterogeneity (I 2 = 84%).

Compared with SIS, SBS showed better stent patency with comparable technical and clinical success and adverse events.

The registration number for this study on PROSPERO is CRD42024523230.

Malignant hilar obstruction (MHO) is considered an aggressive perihilar obstruction caused by cholangiocarcinoma, gallbladder cancer, or metastatic malignancies and has a poor prognosis. Although surgical resection is the only curative treatment method, the majority of patients with MHO do not undergo surgery due to an advanced inoperable state at presentation. Currently, effective biliary drainage provides the necessary palliation for symptomatic improvement. Among the drainage methods, percutaneous access may be preferred, especially for advanced MHO because of the technical difficulty involved with other techniques. Recently, primary endoscopic palliation using plastic or metal stents has been shown to have higher technical feasibility and clinical success without increasing adverse events even in patients with high-degree MHO. The development of various accessories, endoscopic ultrasonography, and advances in techniques have facilitated primary endoscopic intervention. However, some aspects continue to be debated such as the palliation methods, appropriate stents, the number of stents, the deployment methods, and additional local ablation therapies. Therefore, this review discusses the current optimal endoscopic treatment methods for advanced MHO based on reported literature.