The relationship of bile duct crystals to sphincter of Oddi dysfunction.

Bile duct crystals collected either from the duodenum after gallbladder contraction or directly from bile duct aspiration are surrogates for gallbladder stones and microlithiasis. Whether bile crystals also serve as surrogates for bile duct stones or microlithiasis that forms in the bile duct after cholecystectomy is not known based on current data. Sphincter of Oddi dysfunction (SOD), due either to muscular spasm or sphincter fibrosis, is a cause of bile duct obstruction. Almost all of the literature on SOD involves patients who have had a prior cholecystectomy. Intuitively, obstruction at the SO following cholecystectomy would seem to lead to biliary stasis and predispose patients to bile duct microlithiasis. However, a recent study did not find bile duct crystals in patients with manometrically diagnosed SOD. The reason for this is unknown, although we hypothesize that cholesterol and bilirubinate crystals are not surrogates for brown pigment stones commonly found in patients following cholecystectomy.