Endoscopic retrograde stent drainage therapies for malignant biliary obstruction: the distal opening of stent location above or across the duodenal papilla? A systematic review and meta-analysis.

OBJECTIVE: To systematically evaluate the efficacy and safety of the method of placing the distal stent opening above the duodenal papilla (hereinafter referred to Above method) for endoscopic retrograde stent internal drainage in MBO patients. METHODS: PubMed, Embase, Web of science and Cochrane databases were searched to identify clinical studies comparing the stent distal opening mounted above the papilla and across the papilla (hereinafter referred to Across method), Comparison indicators included stent patency, stent occlusion rate, clinical success rate, overall complication rate, postoperative cholangitis rate, and overall survival. Revman5.4 software was used for meta-analysis, funnel plot and publication bias and Egger's test were completed by Stata14.0 software. RESULTS: A total of 11 clinical studies (8 case-control studies, 3 RCT studies) were included, with a total of 751 patients (318 cases in the Above group and 433 cases Across group). The overall patency of Above method was longer than that of Across method (HR = 0.60, 95%CI [0.46-0.78], p < 0.001). Subgroup analysis showed statistical difference using plastic stent (HR = 0.49, 95%CI [0.33,0.73], p < 0.001). Inversely, there didn't exist significant difference in which metal stent were adopted (HR= 0.74, 95%CI [0.46,1.18], p = 0.21). Similarly, there also without statistical difference between patients with plastic stent placed above the papilla and metal stent mounted Across the papilla (HR = 0.73, 95%CI [0.15,3.65], p = 0.70). Moreover, the overall complication rate of the Above method was lower than that of the Across method (OR = 0.48,95%CI [0.30,0.75], p = 0.002). On the contrary, the differences of stent occlusion rate (OR = 0.86,95%CI [0.51,1.44], p = 0.56), overall survival (HR = 0.90, 95%CI [0.71,1.13]), p = 0.36), the clinical success rate (OR = 1.30, 95%CI [0.52,3.24], p = 0.57) and postoperative cholangitis rats (OR = 0.73, 95%CI [0.34,1.56], p = 0.41) were not statistically significant. CONCLUSIONS: The distal opening of the stent can be placed above the duodenal main papilla for eligible MBO patients who receiving endoscopic retrograde stent drainage treatment, which can effectively prolong the patency duration when plastic stent is used, and reduce the overall risk of complications.