Side-by-side versus stent-in-stent bilateral stenting for malignant hilar biliary obstruction: a meta-analysis

Introduction
Both side-by-side (SBS) and stent-in-stent (SIS) bilateral stenting have been used for patients with malignant hilar biliary obstruction (MHBO). However, it is unclear which technique is better.

Aim: This meta-analysis is conducted to investigate the clinical efficacy and safety of SBS and SIS bilateral stenting for patients with MHBO.

Material and methods
Relevant studies were searched in PubMed, Embase, Cochrane Library, Wanfang, VIP, and CINK databases. The timeline for the searches was from the establishment of the database to September 2021. The relative outcomes are pooled.

Results
A total of 7 studies fulfilled the inclusion criteria and entered into this meta-analysis. The pooled technical success rate was significant higher in the SIS group than that in the SBS group (p = 0.04). The pooled early complication rate was significantly lower in the SIS group than in the SBS group (p = 0.04). The pooled stent re-obstruction rate was significantly lower in the SBS group than in the SIS group (p = 0.04). The pooled stent patency duration was significantly longer in the SBS group than in the SIS group (p = 0.01). The pooled functional success rates (p = 0.79), total complication rates (p = 0.34), and overall survival duration (p = 0.27) were comparable between 2 groups. Egger test did not show any publication bias.

Conclusions
When comparing the SBS and SIS bilateral stenting for patients with MHBO, although SIS technique may have the superiorities of technical success and early complication rates, the longer stent patency was achieved by the SBS technique.