[Experimental studies on fistula formation after percutaneous trans-hepatic cholangiodrainage]

The process of intra- and extra-hepatic fistula formation after percutaneous transhepatic cholangiodrainage (PTCD) was investigated. Furthermore, effects of such 4 materials of catheter as vinyl chloride, silicon, polyethylene and poly-urethane on this formation process were compared in order to clarify factors influencing the process. Fistula formation began 2 weeks after PTCD, and nearly completed after 4 weeks. A drainage fistula most markedly formed in the use of vinyl chloride, as the fistula wall was thick and its collagen fibers were microscopically observed to be dense and regularly arranged. On the other hand, fistula walls were thin, and their connective tissues consisted of immature cells and sporadically observed, when the other materials were used. However, degeneration of the liver cells around the intrahepatic fistula was most markedly seen in the use of vinyl chloride. In addition, the fistula formation tended to be more facilitated at early stage when the extrahepatic bile duct was occluded. These results suggested that vinyl chloride is the most suitable material if the drainage is applied for the fistula formation.