Effects of biliary endoprostheses on the extrahepatic bile ducts in relation to subsequent operation of the biliary tract.

Despite the widespread use of transpapillary biliary endoprostheses, little is known about their effect on the extrahepatic bile ducts. In an experimental study in dogs, we induced inflammatory changes in the bile ducts by stent insertion and studied the reversibility of these changes after stent removal. In addition, the consequences of a period of preoperative stenting for subsequent operation of the biliary tract and the eventual detrimental effects of stenting on the histologic factors of the liver were studied. Twenty-six mongrel dogs were randomly divided into four groups: group 1, stenting during four weeks; group 2, after four weeks stenting, construction of a hepaticojejunostomy; group 3, four days of common bile duct (CBD) ligation, four weeks stenting and hepaticojejunostomy, and group 4, four days of CBD ligation and hepaticojejunostomy. All dogs were sacrificed two months after the last procedure. Hepatic biopsies were obtained during each procedure and bile duct biopsies during hepaticojejunostomy and upon sacrifice. Four weeks of stenting of a normal or obstructed CBD resulted in fibrosed bile ducts, showing severe chronic inflammation with papillary hyperplasia of the epithelium. All bile cultures grew fecal bacteria. Two months after stent removal, inflammation was still present, albeit less severe. Stenting and subsequent surgical treatment resulted in a higher incidence of postoperative complications (54 percent) compared with the control group (14 percent), although this did not reach statistical significance. Hepatic histologic factors were not markedly changed after transpapillary endoprosthesis placement, but after hepaticojejunostomy cholangiolitis was observed. Whenever transpapillary biliary endoprostheses are used, the local effects on the extrahepatic bile ducts and the subsequent bacterial contamination of the bile should be considered.