title: Partially covered versus uncovered self-expandable nitinol stents with anti-migration properties for the palliation of malignant distal biliary obstruction: A randomized controlled trial.
abstract: OBJECTIVE
  Covered self-expandable metal stents (SEMSs) are increasingly used as alternatives to uncovered SEMSs for the palliation of inoperable malignant distal biliary obstruction to counteract tumor ingrowth. We aimed to compare the outcomes of partially covered and uncovered SEMSs with identical mesh structures and anti-migration properties, such as low axial force and flared ends.
  
  
  METHODS
  One hundred and three patients who were diagnosed with inoperable malignant distal biliary obstruction between January 2006 and August 2013 were randomly assigned to either the partially covered (n = 51) or uncovered (n = 52) SEMS group.
  
  
  RESULTS
  There were no significant differences in the cumulative stent patency, overall patient survival, stent dysfunction-free survival and overall adverse events, including pancreatitis and cholecystitis, between the two groups. Compared to the uncovered group, stent migration (5.9% vs. 0%, p = 0.118) and tumor overgrowth (7.8% vs. 1.9%, p = 0.205) were non-significantly more frequent in the partially covered group, whereas tumor ingrowth showed a significantly higher incidence in the uncovered group (5.9% vs. 19.2%, p = 0.041). Stent migration in the partially covered group occurred only in patients with short stenosis of the utmost distal bile duct (two in ampullary cancer, one in bile duct cancer), and did not occur in any patients with pancreatic cancer.
  
  
  CONCLUSIONS
  For the palliation of malignant distal biliary obstruction, endoscopic placement of partially covered SEMSs with anti-migration designs and identical mesh structures to uncovered SEMSs failed to prolong cumulative stent patency or reduce stent migration.
authors.affiliation: Department of Gastroenterology, Ajou University School of Medicine , Suwon , South Korea.
authors.forename: Min Jae
authors.initials: MJ
authors.lastname: Yang
authors.forename: Jin Hong
authors.initials: JH
authors.lastname: Kim
authors.forename: Byung Moo
authors.initials: BM
authors.lastname: Yoo
authors.forename: Jae Chul
authors.initials: JC
authors.lastname: Hwang
authors.forename: Jun Hwan
authors.initials: JH
authors.lastname: Yoo
authors.forename: Ki Seong
authors.initials: KS
authors.lastname: Lee
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Kang
authors.forename: Soon Sun
authors.initials: SS
authors.lastname: Kim
authors.forename: Sun Gyo
authors.initials: SG
authors.lastname: Lim
authors.forename: Sung Jae
authors.initials: SJ
authors.lastname: Shin
authors.forename: Jae Youn
authors.initials: JY
authors.lastname: Cheong
authors.forename: Kee Myung
authors.initials: KM
authors.lastname: Lee
authors.forename: Kwang Jae
authors.initials: KJ
authors.lastname: Lee
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Cho
mesh_terms: D000368:Aged; D000497:Alloys; D001650:Bile Duct Neoplasms / Q000601:surgery*; D002764:Cholecystitis / Q000209:etiology*; D020776:Endoscopes, Gastrointestinal; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010166:Palliative Care; D010195:Pancreatitis / Q000209:etiology; D011183:Postoperative Complications / Q000209:etiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D056910:Republic of Korea; D015607:Stents / Q000009:adverse effects* / Q000145:classification; D016896:Treatment Outcome
chemical_list: D000497:Alloys; C013616:nitinol
keywords: malignant biliary obstruction; self-expandable metal stent; stent migration