Common bile duct stones become smaller after endoscopic biliary stenting

Background and Study Aims: Endoscopic biliary stenting is often used for large or difficult common bile duct (CBD) stones that cannot be extracted at one session. We compared the sizes of the CBD stones after a period of stenting. Patients and Methods: Over a 6-year period, a total of 444 patients with large CBD stones (>2 cm diameter) or difficult CBD stones were managed in our endoscopy unit, of which 46 were treated by endoscopic stenting. Twenty-eight had second ERCP for stone removal after a median period of 63 days (range 17-1002 days). The largest diameter of the stones and the CBD (after correction of magnification) before and after stenting were compared using the Wilcoxon signed test. Results: Before stenting the largest diameters of CBD stones were 11-46 mm (mean 24.9 mm) and decreased to 5-46 mm (mean 20.1 mm) after stenting. The difference in stone sizes was statistically significant although the CBD diameter pre- and post-stenting was not significantly different. The reduction in stone sizes was not significantly correlated with the duration of stenting. Conclusion: CBD stones became smaller after stenting. As the difficulty of stone extraction increases with stone size, a period of stenting may make subsequent removal easier for patients with large or difficult CBD stones.