Clinical Impact of Common Bile Duct Angulation on the Recurrence of Common Bile Duct Stone: A Meta-analysis and Review

Background/Aims: Local and systemic factors, such as diabetes, obesity, and hyperlipidemia, are considered risk factors for the recurrence of choledocholithiasis after successful endoscopic clearance. Local factors include the presence of bile sludge, common bile duct (CBD) diameter, and CBD angulation. Among them, it is unclear if acute CBD angulation is preferable to the recurrence of a CBD stone. Methods: PubMed, EMBASE, CINAHL, the Cochrane Library databases, and google website were searched for randomized controlled trials reported in English and undertaken until August 2019. Meta-analysis was performed on all randomized controlled trials for the recurrence of CBD stones between the patients with acute CBD angulation. Results: Eight randomized trials (1,776 patients) were identified, and the total recurrent rate of CBD stones was 18.8% (334/1,776). A CBD angle ≤145° was significantly associated with an increased risk of recurrent CBD stone (OR=2.65, p<0.01). In two prospective studies, acute CBD angulation was not proven to be associated with a recurrence (p=0.39). Conclusions: Approximately 20% of patients with a CBD stone showed recurrence after the complete clearance of the CBD stone, and a CBD angle ≤145° could increase the risk of recurrence. Overall, a large-scale prospective study should be necessary.