title: Percutaneous cholangioscopy in obstructed biliary metal stents.
abstract: OBJECTIVE
  To reevaluate the reasons for the occlusion of self-expanding biliary metal stents, on the basis of cholangioscopic findings.
  
  
  METHODS
  Percutaneous transhepatic cholangioscopy (PTCS) was performed in 15 patients with obstructed biliary Wallstents. The reason for stent insertion was a malignant obstruction in 14 patients; 1 had a benign biliary stricture. Conventional noncovered stents had been inserted in 12 patients; in 3 cases a polyurethanecovered prototype Wallstent had been used. Stent occlusions occurred after 1-55 months. PTCS was performed with a 2.3-mm endoscope through an 11 Fr sheath. Biopsies were taken via the working channel of the endoscope.
  
  
  RESULTS
  In all patients with noncovered stents the inner surface of the stent was highly irregular with seaweed-like protrusions (biopsy-proven granulation tissue). Stent incorporation varied from absent (n = 1) to subtotal (n = 8), but was always incomplete, no matter how long the stent had been in place. Tumor ingrowth was histologically proven in 2 patients. One patient had a large occluding concrement at the proximal end of the stent. In patients with covered stents, the inner surface appeared more regular; however, viable granulation tissue was found inside two stents and tumor ingrowth in one of them.
  
  
  CONCLUSIONS
  PTCS showed that incorporation of the stent is virtually always incomplete. The factors contributing most to stent occlusion are the buildup of granulation tissue, bile sludge, and tumor overgrowth. Stone formation and tumor ingrowth can also be important, although less common causes of occlusion. A polyurethane stent covering could not prevent tumor ingrowth in one patient and the buildup of viable granulation tissue inside the stent in two further patients; mean stent patency in the three patients with such a stent was 3 months.
authors.affiliation: Department of Radiology, Karl-Franzens Universität Graz, Austria.
authors.forename: K A
authors.initials: KA
authors.lastname: Hausegger
authors.forename: H J
authors.initials: HJ
authors.lastname: Mischinger
authors.forename: R
authors.initials: R
authors.lastname: Karaic
authors.forename: G E
authors.initials: GE
authors.lastname: Klein
authors.forename: C
authors.initials: C
authors.lastname: Kugler
authors.forename: R
authors.initials: R
authors.lastname: Kern
authors.forename: M
authors.initials: M
authors.lastname: Uggowitzer
authors.forename: D
authors.initials: D
authors.lastname: Szolar
mesh_terms: D000368:Aged; D001646:Bile; D001650:Bile Duct Neoplasms / Q000150:complications; D017734:Bile Ducts, Extrahepatic / Q000473:pathology*; D001653:Bile Ducts, Intrahepatic / Q000473:pathology*; D001706:Biopsy; D002779:Cholestasis / Q000175:diagnosis* / Q000209:etiology; D001651:Cholestasis, Extrahepatic / Q000175:diagnosis* / Q000209:etiology; D003251:Constriction, Pathologic / Q000175:diagnosis; D016145:Endoscopy, Digestive System; D005260:Female; D006097:Granulation Tissue / Q000473:pathology; D006801:Humans; D008297:Male; D010190:Pancreatic Neoplasms / Q000150:complications; D015607:Stents