title: Multicenter randomized trial of the spiral Z-stent compared with the Wallstent for malignant biliary obstruction.
abstract: BACKGROUND
  The industry standard since 1990 for self-expanding biliary metallic stents has been the Wallstent. In 1998 the Spiral Z-stent was released. This randomized trial compared the Z-stent with the Wallstent in the treatment of malignant biliary obstruction.
  
  
  METHODS
  Patients with unresectable malignant biliary obstruction distal to the bile duct bifurcation were randomized to receive a 10-mm diameter Wallstent or a 10-mm diameter Z-stent.
  
  
  RESULTS
  A total of 145 patients were randomized; 13 were excluded. Sixty-four patients who received a Z-stent and 68 who had a Wallstent are included in the analysis. Tumors responsible for bile duct obstruction were pancreatic cancer (108), cholangiocarcinoma (15), metastatic cancer (6), and papillary cancer (3). Metallic stents were successfully placed in all patients. Seven technical problems were encountered during placement of the Z-stent and 5 with the Wallstent. There were 21 occlusions requiring reintervention (8 Z-stent, 13 Wallstent; p = 0.30). Median time to reintervention was the following: Z-stent, 162 days; Wallstent, 150 days (p = 0.22). A total of 104 patients died of progressive disease or other cause; 7 patients remain alive with patent stents. The overall calculated median patency rates were: Z-stent, 152 days; Wallstent, 154 days (p = 0.90).
  
  
  CONCLUSIONS
  The Spiral Z-stent is comparable with the Wallstent in terms of placement, occlusion rates, and overall patency. Occasional early occlusion of both stents suggests tumor characteristics instead of the size of the mesh openings in the stents as important factors.
authors.affiliation: Maine Medical Center, Portland, Maine, USA.
authors.forename: Raj J
authors.initials: RJ
authors.lastname: Shah
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Howell
authors.forename: David J
authors.initials: DJ
authors.lastname: Desilets
authors.forename: Sunil G
authors.initials: SG
authors.lastname: Sheth
authors.forename: Willis G
authors.initials: WG
authors.lastname: Parsons
authors.forename: Patrick
authors.initials: P
authors.lastname: Okolo
authors.forename: Glen A
authors.initials: GA
authors.lastname: Lehman
authors.forename: Stuart
authors.initials: S
authors.lastname: Sherman
authors.forename: John
authors.initials: J
authors.lastname: Baillie
authors.forename: M Stanley
authors.initials: MS
authors.lastname: Branch
authors.forename: Douglas
authors.initials: D
authors.lastname: Pleskow
authors.forename: Ram
authors.initials: R
authors.lastname: Chuttani
authors.forename: John J
authors.initials: JJ
authors.lastname: Bosco
mesh_terms: D000368:Aged; D002779:Cholestasis / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010166:Palliative Care; D011474:Prosthesis Design; D015607:Stents