## INTRODUCTION

With advanced endoscopic and laparoscopic techniques readily accessible to the treating surgeon, determining the wisest path to the successful treatment of choledocholithiasis and cholangitis has become more challenging. Nevertheless, a large number of options allow one to tailor specific therapy to each individual clinical situation in order to achieve the highest probability of safety and success. In this chapter, we offer the reader a review of the methods available for the diagnosis and treatment of common bile duct (CBD) stones and cholangitis so that treatment plans can be developed that are patient-specific and have the highest chance of success.

## CHOLEDOCHOLITHIASIS

### Classification and Epidemiology

A common entity in Western societies, gallstones are found in approximately 15% of Americans and result in 700,000 cholecystectomies a year. The annual cost of medical care for gallstones is almost $6.5 billion compared with colorectal cancer ($9.5 billion), viral hepatitis ($3.4 billion), and gastroesophageal reflux disease (GERD) ($12.6 billion).1,2 CBD (downstream of the confluence of the hepatic ducts) stones have been noted in 10% to 15% of patients with cholelithiasis, and this incidence increases with age to over 80% in those who are over 90 years old.3 Choledocholithiasis in Western countries usually results from stones originating in the gallbladder and migrating through the cystic duct. These secondary bile duct stones are cholesterol stones in 75% and black pigment stones in 25% of patients. Cholesterol stones contain more than 70% cholesterol by weight, and variable amounts of bile salt and calcium. Over 90% of all cholesterol stones are radiolucent. Cholesterol stones are formed in the presence of cholesterol saturation, biliary stasis, and nucleating factors. Behavioral factors associated with cholesterol gallstones include nutrition, obesity, weight loss, and physical activity. Biologic factors linked to gallstones include increasing age, female sex and parity, serum lipid levels, and the Native American, Chilean, and Hispanic races.1 The formation of black pigment stones is associated with hemolytic disorders, cirrhosis, ileal resection, prolonged fasting, and total parenteral nutrition.3 These conditions lead to supersaturation of unconjugated bilirubin, which results in precipitation of bilirubinate with calcium and other anions in bile. The precipitated salt then becomes a nidus for black stone formation.

Primary bile duct stones, on the other hand, form within the bile ducts and usually are of the brown pigment variety. These tend to be less than 20% cholesterol and higher in bilirubin content as compared with secondary stones. Unlike secondary stones, primary stones are associated with biliary stasis and bacteria.4 In fact, in the pathogenesis of brown pigment stones, bacterial enzymes unconjugate bilirubin glucuronide to form free bilirubin, which then precipitates with calcium to become the nidus for stone formation.5 Moreover, bacteria have been found in brown pigment stones by electron microscopy but not in black pigment stones.

Primary bile duct stones are more common in ...

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