UTILITY OF BILIARY MICROCRYSTAL ANALYSIS IN PREDICTING COMPOSITION OFCOMMON BILE-DUCT STONES

The high failure rate of contact litholytic therapy for common bile du ct stones with currently available cholesterol solvents has been attri buted to the inclusion of patients with pigment stones, as no pretreat ment investigation is undertaken to distinguish the two stone types. I n 36 patients with common bile duct stones we prospectively evaluated the utility of microscopic examination of bile collected from the bili ary tree in predicting stone composition. The bile, obtained by means of either an endoscopically placed nasobiliary catheter (n = 27) or a surgically placed T-tube (n = 9), was subjected to microscopic examina tion, and findings were compared with the composition of stones retrie ved subsequently. On the basis of quantitative infrared spectroscopy, stones were classified as cholesterol (n = 28) or pigment (n = 8) ston es. The presence of cholesterol crystals in bile correctly identified 24 of 28 patients with cholesterol stones (sensitivity, 86%; specifici ty, 100%; positive predictive value, 100%). Calcium bilirubinate granu les, when present alone (without cholesterol crystals), correctly iden tified all eight patients with pigment stones (sensitivity, 100%; spec ificity, 89%; positive predictive value, 73%). Thus, microscopic exami nation of bile from the biliary tree, if used as a pretreatment screen ing test, may help distinguish between patients with cholesterol and p igment stones and thereby considerably improve the results of litholyt ic therapy of common bile duct stones with currently available solvent s.