The effect of spiral basket geometry on procedural efficiency and device escalation in small bile duct stones: a multicenter randomized controlled trial (ESCAPE trial)

Background: The optimal first-line device for endoscopic retrograde cholangiopancreatography (ERCP) removal of small common bile duct stones (CBDS) remains uncertain. Whether basket geometry - independent of device category - influences procedural efficiency has not been evaluated in a randomized trial. We aimed to compare a spiral-configured 8-wire basket with a standard 8-wire basket for small CBDS. Methods: In this multicenter randomized controlled trial, patients with CBDS ≤8 mm were randomly assigned (1:1) to stone extraction using a standard or spiral-configured 8-wire basket. Results: Among 200 randomized patients, 193 underwent basket insertion (spiral group 97, standard group 96). First-line procedural success without device escalation within 10 minutes was significantly higher in the spiral group (97.9% vs. 85.4%; 95%CI 4.9 to 20.1; P = 0.004), corresponding to a number-needed-to-treat of 8. The spiral basket required fewer sweeps (mean [SD]: 2.71 [1.41] vs. 3.31 [1.67]; P = 0.01) and shorter procedure time (3.96 [2.86] vs. 5.48 [4.38] minutes; P = 0.01). Adverse event rates were comparable between groups. Mean device-related costs were lower in the spiral group (mean difference -108 USD; bootstrap 95%CI -185 to -42). Conclusions: A spiral basket configuration improved early procedural efficiency and reduced device escalation and device-related costs, without improving the final stone clearance rate or increasing adverse events. The spiral basket was not compared with balloon extraction and should not be interpreted as superior to it. Although the device evaluated is currently available primarily in Japan, the geometric principle underlying its advantage may inform device development more broadly.