Transient obstruction of the common bile duct following its exploration.

Failure of the contrast medium to enter the duodenum during the operative cholangiography following the common bile duct exploration and instrumentation may be caused by transient obstruction of the common bile duct. It is attributed to spasm and oedema of the sphincter choledochus of Boyden and not of the sphincter of Oddi. The knowledge of the possibility of the pseudo-obstruction of the common bile duct following its exploration may save the surgeon from unnecessary re-exploration and performing sphincterotomy or choledochoduodenostomy. The exploration is unnecessary if, during the common duct exploration, the dilators and the catheter passes easily into the duodenum and on the cholangiogram the obstructed area is smooth and there is no filling defect. A normal cholangiogram performed 8-10 days following the operation proves that the obstruction was transient and not caused by calculus stricture or tumour.