Consistent with standards from some previous studies, the following were our standards for primary closure of CBD: diameter of CBD ≥ 8 mm, both stones in CBD and within intrahepatic bile duct thoroughly extracted, mild inflammation of CBD wall, patent distal CBD and major duodenal papilla, well functional Oddi’s sphincter, and without severe injuries to supplying vessels of CBD. In theory, distance between incision and supplying vessels (at 3 o’clock and 9 o’clock of common bile duct) and frequency of using electrocoagulation are two main factors contributing to injuries to supplying vessels.