Objective To evaluate the angle of extrahepatic biliary tract using magnetic resonance cholangiopancreatography (MRCP), and to investigate its clinical value in predicting the risk of biliary tract injury (BDI) during laparoscopic cholecystectomy (LC).
Methods The retrospec-tive and descriptive study was conducted. The clinical data of 416 patients undergoing MRCP before LC who were admitted to The Affiliated Hospital of Inner Mongolia Medical University from January 2021 to December 2024 were collected. There were 88 males and 328 females, aged 53 (17, 76) years. The angle between the extension line of lower segment of common bile duct and the upper segment of duodenal bile duct in coronal and sagittal MRCP was defined as the approach angle and the exposure angle, respectively. Patients were divided into 4 groups based on the angle of extrahepatic biliary tract. The consistency of intra class correlation coefficient (ICC) was checked. Observation indicators: (1) MRCP for the angle of extrahepatic biliary tract; (2) comparison of clinicopathological data among 4 groups; (3) comparison of BDI among 4 groups. Comparison of count data between groups was conducted using the chi‑square test.
Results (1) MRCP for the angle of extrahepatic biliary tract: all 416 patients completed MRCP for the angle of extrahepatic biliary tract and the average angle was calculated. The approach angle was 39.5°±12.2°, and the exposure angle was 29.0°±11.6°. The ICC of intra measure consistency was 0.91(95% confidence interval as 0.87-0.95), and the ICC of inter measure consistency was 0.89(95% confidence interval as 0.83-0.92), indicating good consistency. (2) Comparison of clinicopathological data among 4 groups: for the 4 groups of 416 patients, there were 103 patients in group 1, 89 patients in group 2, 96 patients in group 3, and 128 patients in group 4. There was no significant difference in gender, age, common bile duct width and pathological examination among the 4 groups (P>0.05). (3) Comparison of BDI among 4 groups: a total of 5 cases of the 4 groups with BDI were all from the group 1. The approach angle and exposure angle of 5 patients with BDI were higher than the average value.
Conclusions There is a certain angle in the direction of extrahepatic biliary tract, and the coronal approach angle is 39.5°±12.2°, the sagittal exposure angle is 29.0°±11.6°. Before LC, MRCP can be used to evaluate the angle between the extension line of the lower common bile duct and the upper segment of duodenal bile duct. When the approach angle and exposure angle are both higher than their average values, there is a risk of BDI during operation.
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