Stones in the common bile duct.

I wanted to consider whether stones can form or stay in the common bile duct for long periods of time and whether they are passable. Several people here have reported passing large stones. I suppose it make sense, in that stones when softened can be squished through a small hole. I understand what malic acid does in softening - I've already ordered some. I don't really understand how GCG crushes stones - I have some already. Anyway, I ran accross a web page that discusses a case study of a man who had a giant stone in the common bile duct ( 3.5" x 1.5" and weighing 55 gms.)

http://www.jpgmonline.com/article.asp?issn=0022-3859;year=1982;volu...