title: High single-session success rate of endoscopic bilateral stent-in-stent placement with modified large cell Niti-S stents for malignant hilar biliary obstruction.
abstract: BACKGROUND
  Endoscopic bilateral self-expandable metallic stent (SEMS) placement in a stent-in-stent method for malignant hilar biliary obstruction is technically challenging. Technical difficulties in the initial placement and reinterventions for stent occlusion are disadvantages inherent to this stent-in-stent method. We previously reported the feasibility of Niti-S large cell D-type biliary stents (LCD). This multicenter prospective consecutive study evaluated the efficacy of bilateral SEMS placement using modified LCD with large and uniform cells, a slimmer delivery system and high radial force.
  
  
  METHODS
  From July 2010 to June 2011, 26 consecutive patients with unresectable malignant hilar biliary obstruction underwent endoscopic bilateral placement of modified LCD in a stent-in-stent method at three tertiary hospitals. Ten patients had gallbladder cancer, eight had cholangiocarcinoma, four had lymph node metastasis, two had intrahepatic cholangiocarcinoma, and two had liver metastasis.
  
  
  RESULTS
  Single-session and final technical success rate was 96% and 100%, respectively. Functional success rate was 89%. Stent occlusion occurred in 11 patients (42%) because of sludge (n = 7) or tumor ingrowth (n = 4). Endoscopic bilateral reintervention was technically easy and successful: six patients had stent clearance by balloon sweeping and five had plastic stent placement. According to Kaplan-Meier analysis, median survival and stent patency were 220 days and 157 days, respectively.
  
  
  CONCLUSIONS
  Modified LCD achieved a high technical success rate both in the initial stent-in-stent placement and in bilateral reinterventions in patients with malignant hilar biliary obstruction.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kogure
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isayama
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Nakai
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tsujino
authors.forename: Saburo
authors.initials: S
authors.lastname: Matsubara
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yashima
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Ito
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Hamada
authors.forename: Naminatsu
authors.initials: N
authors.lastname: Takahara
authors.forename: Koji
authors.initials: K
authors.lastname: Miyabayashi
authors.forename: Suguru
authors.initials: S
authors.lastname: Mizuno
authors.forename: Dai
authors.initials: D
authors.lastname: Mohri
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Kawakubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Natsuyo
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Hirano
authors.forename: Naoki
authors.initials: N
authors.lastname: Sasahira
authors.forename: Minoru
authors.initials: M
authors.lastname: Tada
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000150:complications; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000150:complications; D002779:Cholestasis / Q000601:surgery*; D004067:Digestive System Neoplasms / Q000150:complications* / Q000601:surgery*; D016145:Endoscopy, Digestive System / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D005706:Gallbladder Neoplasms / Q000150:complications; D006801:Humans; D057194:Intention to Treat Analysis; D053208:Kaplan-Meier Estimate; D008297:Male; D011446:Prospective Studies; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000379:methods*; D015607:Stents
keywords: bilateral biliary drainage; endoscopic retrograde cholangiopancreatography (ERCP); malignant hilar biliary obstruction; self-expandable metallic stent (SEMS); stent-in-stent