Endoscopic metal stenting for malignant hilar biliary obstruction: an update meta-analysis of unilateral versus bilateral stenting

Introduction
Malignant hilar biliary obstruction (MHBO) can arise in patients with malignant hilar hepatobiliary tumors or lymph nodules. Most MHBO patients are not suitable for surgical resection due to the advanced tumor stage. The only palliative treatment available is provided by endoscopic or percutaneous stenting. Aim: To compare the efficacy of endoscopic unilateral versus bilateral metal stent insertion for treating MHBO.

Material and methods
A search of the PubMed, Embase, and Cochrane Library databases identified all relevant studies published until June 2020. The meta-analysis was undertaken using RevMan v5.3.

Results
We identified 154 studies initially, eight of which were used in our meta-analysis. The eight studies included 818 MHBO patients treated using either endoscopic unilateral (n = 396) or bilateral (n = 422) metal stenting. No significant differences were observed between the two groups in clinical success rate (OR = 2.64; p = 0.18), complication rate (OR = 0.63; p = 0.46), or OS (HR = 1.03; p = 0.53). The bilateral group had a lower stent dysfunction rate without significance (OR = 1.43; p = 0.09). Significantly longer stent patency was observed in the bilateral group (HR = 1.28; p = 0.01). Technical success rate was significantly higher in the unilateral group (OR = 0.26; p = 0.04). Funnel plot analysis indicated an absence of publication bias related to the selected study endpoints.

Conclusions
Our meta-analysis indicated that endoscopic unilateral stenting had a greater technical success rate for MHBO patients than bilateral stenting. However, the bilateral stenting could achieve longer stent patency.