Association of types of periampullary diverticulum and types of extrahepatic bile duct stones: a cross-sectional study

Abstract

Background/Aims:
Periampullary divertcula are associated with an increased incidence of choledocholithiasis. There are diferent types of divertcula based on its locaton relatve to the major papilla, and there are diferent types of bile duct stones. This study aims to determine the relatonship between the types of divertcula and the types of duct stones.

Methods:
This is a cross-sectonal study of 380 patents with choledocholithiasis and who underwent ERCP from February 2015 to October 2020. Ofcial reports and videos were reviewed. Outcome measures include types of periampullary divertcula using the Li-Tanaka Classifcaton and types of bile duct stones. T-test and Chi-square Goodness of Fit test were used for data analysis.

Results:
There were 275 patents with no divertcula and 105 patents with divertcula. Type III (papilla ≥1 cm outside the divertculum margin) was most common (42.85%). There was signifcantly diferent age between the groups (p<0.001) with Type IVa (2 divertcula with papilla <1 cm outside the margins of at least one) having the highest mean age of 67.45±15.9 years. There was also a signifcant diference in failed cannulaton (p<0.01) with Type IVa having 27%. Though there was no signifcant diference in duct diameters, duct stone numbers, and duct stone sizes, Types I (intradivertcular papilla not adjacent to the margin) and IIa had larger duct diameters (1.7±0.71 cm and 1.54±0.55 cm respectvely), more multple duct stones (50% and 75%, respectvely), and larger duct stone sizes (1.3±0.85 cm and 1.56±0.75 cm, respectvely). There was a signifcant diference in the types of stones with Type IVa having 71% brown stones, p=0.018).

Conclusion: Type of periampullary divertculum may infuence the type of stone in the extrahepatc bile duct, with Type IVa having the highest proporton of brown stones. Type IVa was also associated with failed cannulaton and older age.