title: Small cell- versus large cell-sized metal stent in endoscopic bilateral stent-in-stent placement for malignant hilar biliary obstruction.
abstract: OBJECTIVE
  Although the large cell-sized biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent for stent-in-stent (SIS) technique, there are concerns about its vulnerability to tumor ingrowth. The aim of the present study was to compare the clinical outcomes of endoscopic bilateral SIS placement according to the cell size of a self-expandable metallic stent (SEMS).
  
  
  METHODS
  A total of 58 patients were enrolled who underwent endoscopic bilateral SIS placement of SEMS for malignant hilar biliary obstruction as a result of cholangiocarcinoma or gallbladder cancer. Finally, 43 patients who underwent successful stent insertion were included in the analysis and divided into the small cell-sized stent (SCS; n = 21) and the large cell-sized stent (LCS; n = 22) groups. We retrospectively compared comprehensive clinical and laboratory data in both groups.
  
  
  RESULTS
  There were no significant differences between the two groups in successful drainage (SCS vs LCS, 100% vs 100%, respectively), early complications (38.1% vs 18.2%), late complications (14.3% vs 22.7%), stent occlusion (42.9% vs 45.5%), tumor ingrowth (33.3% vs 45.5%) or overgrowth (9.5% vs 0%). Duration of stent patency and overall survival were not significantly different between the two groups (P = 0.086 and P = 0.320, respectively).
  
  
  CONCLUSIONS
  Endoscopic bilateral SIS placement for malignant hilar biliary obstruction shows no differences in stent patency, survival, complications and clinical course according to the cell size of SEMS.
authors.affiliation: Departments of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.|Department of Internal Medicine, Gyeongsang National University College of Medicine, Gyeongsang National University Hospital, Jinju, Korea.
authors.forename: Jae Min
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Departments of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
authors.forename: Sang Hyub
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Departments of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Chung
authors.affiliation: Department of Internal Medicine, Kangwon National University School of Medicine, Kangwon National University Hospital, Chuncheon, Korea.
authors.forename: Jin Myung
authors.initials: JM
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Inje University Ilsan Paik Hospital, Goyang, Korea.
authors.forename: Woo Hyun
authors.initials: WH
authors.lastname: Paik
authors.affiliation: Center for Liver Cancer, National Cancer Center, Goyang, Korea.
authors.forename: Sang Myung
authors.initials: SM
authors.lastname: Woo
authors.affiliation: Center for Liver Cancer, National Cancer Center, Goyang, Korea.
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: Departments of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
authors.forename: Ji Kon
authors.initials: JK
authors.lastname: Ryu
authors.affiliation: Departments of Internal Medicine and Liver Research Institute, Seoul National University Hospital, Seoul, Korea.
authors.forename: Yong-Tae
authors.initials: YT
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging; D018281:Cholangiocarcinoma / Q000150:complications* / Q000000981:diagnostic imaging; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000379:methods; D002780:Cholestasis, Intrahepatic / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy*; D015331:Cohort Studies; D005260:Female; D005706:Gallbladder Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010166:Palliative Care; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D015607:Stents; D015996:Survival Rate; D014463:Ultrasonography
keywords: cell size; endoscopic retrograde cholangiopancreatography (ERCP); malignant hilar biliary obstruction; self-expandable metallic stent (SEMS); stent-in-stent