title: Covered versus uncovered wallstent for malignant extrahepatic biliary obstruction: a cohort comparative analysis.
abstract: OBJECTIVE
  We examined the use of both covered and uncovered Wallstents in patients with malignant extrahepatic biliary obstruction to determine whether use of covered Wallstents prolonged stent patency without increasing procedure-related complications.
  
  
  METHODS
  Commercially available silicone-covered Wallstents were prospectively evaluated in 98 patients who underwent insertion from December 2002-December 2004. Those data were compared with data obtained by retrospectively studying 108 consecutive patients who underwent endoscopic insertion of uncovered Wallstents between January 2000-November 2002, and for whom accurate and complete follow-up details were available.
  
  
  RESULTS
  The mean stent patency was similar for both groups, 148.9 days (range, 3-667 days) for covered Wallstents and 143.5 days (3-910 days) for uncovered Wallstents (P = .531). The 2 groups also did not significantly differ in terms of cumulative stent patency according to the Kaplan-Meier lifetime table. The incidence of mild pancreatitis was similar in both groups, occurring in 6 patients with covered stents (6/98, 6.1%) and 2 patients with uncovered stents (2/108, 1.9%) (P = .154). Excluding those patients who had previously undergone cholecystectomy, acute cholecystitis occurred in 5 of 88 patients with covered Wallstents (6.1%) and 1 of 100 patients with uncovered stents (1%) (P = .104). Stent migration occurred in 6 patients with covered stents (6.1%) and 0 patients with uncovered stents (P = .011).
  
  
  CONCLUSIONS
  Covered Wallstents might not prolong stent patency compared with uncovered Wallstents when used in the management of malignant extrahepatic biliary obstruction.
authors.affiliation: Department of Internal Medicine, Soon Chun Hyang University Cheonan Hospital, Cheonan, Korea.
authors.forename: Do Hyun
authors.initials: DH
authors.lastname: Park
authors.forename: Myung-Hwan
authors.initials: MH
authors.lastname: Kim
authors.forename: Jung Sik
authors.initials: JS
authors.lastname: Choi
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Lee
authors.forename: Dong Wan
authors.initials: DW
authors.lastname: Seo
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Kim
authors.forename: Jimin
authors.initials: J
authors.lastname: Han
authors.forename: Jong Cheol
authors.initials: JC
authors.lastname: Kim
authors.forename: Eun Kwang
authors.initials: EK
authors.lastname: Choi
authors.forename: Sung Koo
authors.initials: SK
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001661:Biliary Tract Neoplasms / Q000150:complications*; D002764:Cholecystitis / Q000209:etiology; D001651:Cholestasis, Extrahepatic / Q000209:etiology / Q000601:surgery*; D020099:Coated Materials, Biocompatible / Q000009:adverse effects; D005260:Female; D006801:Humans; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000209:etiology; D012828:Silicones; D015607:Stents / Q000009:adverse effects; D015996:Survival Rate
chemical_list: D020099:Coated Materials, Biocompatible; D012828:Silicones