目的：应用计算流体力学软件结合有限元法对胆胰管汇合部解剖结构进行2D数值模拟，分析胆胰壶腹隔膜、十二指肠乳头开口方向和形状对隐匿性胰胆反流(occult pancreaticobiliary reflux, OPBR)的影响。方法：利用网上资料获得胆胰管汇合部解剖结构数据。通过计算流体力学Fluent 2020R2软件2D重建。将胆胰管汇合部按以下条件绘制出不同模型：胆胰壶腹隔膜（有/无）、十二指肠乳头开口方向（偏向胆管/居中/偏向胰管），共6组模型，分析引起OPBR的危险因素。结果：在胆胰管汇合部解剖结构正常情况下，即壶腹隔膜存在，无论十二指肠乳头形状和开口方向如何改变，均未见胰胆反流。当壶腹隔膜缺失导致共同通道>5 mm，十二指肠乳头偏向胆管侧时，胰液少量反流进入胆管下端；当壶腹隔膜缺失导致共同通道>5 mm，十二指肠乳头居中时，反流进入胆管内的胰液流速、流量增大，反流程度维持在胆管下端；当壶腹隔膜缺失导致共同通道>5 mm，十二指肠乳头偏向胰管侧时，胰胆反流程度更严重，胆管全程可见胰液反流。在此反流模型基础上缩短胆胰管共同通道长度，扩大流出道开口后，胰胆反流现象消失。结论：基于Fluent研究发现，壶腹隔膜、十二指肠乳头等解剖结构与OPBR的发生密切相关，通过缩短胆胰管共同通道长度、扩大流出道开口可终止胰胆反流。

Objective Computational fluid dynamics software combined with finite element method was used to conduct 2D numerical simulation of pancreaticobiliary junction, and analyze the influence of biliopancreatic ampullary diaphragm, opening direction and shape of duodenal papilla on occult pancreaticobiliary reflux(OPBR). Methods The data of anatomical structure of pancreaticobiliary junction were obtained from online information. Pancreaticobiliary junction was reconstructed in 2D by computational fluid dynamics Fluent 2020R2 software. Different models were drawn for the pancreaticobiliary junction according to the following parameters: biliopancreatic ampullary diaphragm (with/without), opening direction of duodenal papilla(biased to the side of bile duct/central/biased to the side of pancreatic duct). A total of 6 models were used to analyze the risk factors for OPBR. Results When the anatomical structure of the biliopancreatic duct confluence was normal, that was, the ampullary diaphragm exists, no matter how the shape of the duodenal papilla and the opening direction changed, there was no pancreaticobiliary reflux. When the common channel was >5 mm due to the absence of the ampullary diaphragm and duodenal papilla was biased to the side of bile duct, a small amount of pancreatic juice refluxed into the lower end of the bile duct. When the common channel was >5 mm due to the absence of the ampullary diaphragm and duodenal papilla open position was in the middle of the biliopancreatic duct, the velocity and flow rate of pancreatic juice entering bile duct increased, and the degree of reflux was maintained at the lower end of the bile duct. When the common channel was >5 mm due to the absence of the ampullary diaphragm and the duodenal papilla was biased to the side of pancreatic duct, the degree of pancreaticobiliary reflux was more serious, and pancreatic juice reflux was observed throughout the entire bile duct. On the basis of this reflux model, the length of common channel of biliopancreatic duct was shortened, and the opening of outflow tract was enlarged, and the phenomenon of pancreaticobiliary reflux disappeared. Conclusions Based on the Fluent study, it is found that anatomical structures such as ampullary diaphragm and duodenal papilla were closely related to the occurrence of OPBR. Pancreaticobiliary reflux can be terminated by shortening the common channel length of pancreaticobiliary junction and expanding the opening of outflow tract.