Fig. 1. Evaluation of large oral protrusions. A large oral protrusion was defined as the ratio of the length of the oral protrusion to the transverse diameter of the papilla ≥2 (yellow arrows).

Fig. 2. Primary precut sphincterotomy. (A) Evaluation of the large oral protrusion. (B) Primary precut sphincterotomy. (C) Exposure of the bile duct orifice by primary precut sphincterotomy. (D) Biliary duct cannulation.

Graphical abstract