OBJECTIVETo assess the efficacy and safety of bilateral versus unilateral biliary drainage in malignant hilar obstruction.

METHODSTopically relevant studies,regardless of randomized or observational design, were searched for in PubMed, EmBase and the Cochrane Library database. Risk ratios (RRs) with 95% confidence intervals (CIs) were calculated to compare the effect of the two treatments.

RESULTSThree randomized trials and 7 observational studies were included, involving 894 patients with malignant hilar obstruction. The meta-analysis assessment of primary outcomes showed that the stent patency rate was better in bilateral drainage than in unilateral drainage (Rr=2.03,95% CI [1.16-3.56], P=0.01), but there were no significant differences in successful drainage rate (Rr=1.07,95% CI [0.97-1.18], P=0.20) and patient survival rate (Rr=-0.16,95% CI [-0.40-0.08], P=0.20). In the analysis of secondary outcomes,there were also no significant differences in the technical success rate (Rr=1.05,95% CI [0.98-1.17], P=0.34),the early complication rate (Rr=1.15, 95% CI [0.75-1.76], P=0.52), late complication rate (Rr=1.09,95% CI [0.75-1.60], P=0.60) and 30-day mortality rate (Rr=0.68,95% CI [0.38-1.23], P=0.20).

CONCLUSIONAlthough the cumulative stent patency was better for the bilateral than the unilateral drainage approach, based on the available data, there is not enough data to support bilateral drainage for malignant hilar obstruction. Well-designed randomized controlled trials are necessary to confirm it.