Direct comparison of simultaneous and sequential endoscopic metallic bilateral stenting in malignant hilar biliary obstruction

BACKGROUND Endoscopic bilateral biliary drainage is a first line palliative treatment for unresectable malignant hilar biliary obstruction (MHBO) but remains technically challenging. The emergence of self-expandable metallic stents carried by an ultra-thin (6 Fr or smaller) delivery system now permits simultaneous bilateral stent placement. To date, only a few studies have compared this new method with conventional sequential bilateral stenting. AIM To evaluate a possible superiority of simultaneous "side by side" (SBS) biliary drainage in unresectable MHBO. METHODS We identified 135 patients who benefited from bilateral drainage using uncovered self-expandable metallic stents between 2010 and 2023. Among them, 62 benefited from simultaneous SBS bilateral drainage between 2017 and 2023, and 73 benefited from sequential bilateral drainage [38 using "stent in stent" (SIS) technique and 35 using SBS technique between 2010 and 2017]. RESULTS Technical success was significantly increased in simultaneous drainage compared with sequential drainage (94% vs 75%, P = 0.008). However, simultaneous SBS drainage and sequential SIS drainage had a similar technical success (94% vs 95%). We observed no differences regarding clinical success, procedure duration and recurrent biliary obstruction rate. Stent patency was shorter in the SIS group compared with the simultaneous group (103 days vs 144 days). Early adverse events were more frequent in the sequential group (31% vs 21%, P = 0.205), with no differences regarding SIS or SBS technique. Technical failure was associated with a higher rate of infectious fatal adverse events (9.5% vs 1.7%, P = 0.02). Reintervention after recurrent biliary obstruction seems to be more successful after using SBS rather than SIS techniques (83% vs 75%, P = 0.53). CONCLUSION Simultaneous SBS metallic stent placement using an ultra-thin delivery system was technically easier and as efficient as sequential bilateral stenting in unresectable MHBO to achieve bilateral drainage. The SIS procedure remains a good option in unresectable MHBO.