title: No Distal Migration in Unfixed Versus Fixed Cell Structure Covered Self-Expanding Metal Stents for Treatment of Benign Biliary Disease.
abstract: BACKGROUND
  Fully covered self-expandable metal stents (FCSEMS) are increasingly used for treatment of benign common bile duct (CBD) stricture or leakage, but dislodgement of FCSEMS is frequent.
  
  
  OBJECTIVE
  To compare dislocation rate and clinical outcome of a standard fixed cell structure FCSEMS (S-FCSEMS) to a novel FCSEMS with an unfixed cell structure (N-FCSEMS).
  
  
  METHODS
  We performed a retrospective analysis of all patients with FCSEMS insertion for benign biliary disease at our Hospital from 03/2008 to 03/2014. Both stent types N-FCSEMS and S-FCSEMS were applied as available unrelated to the indication.
  
  
  RESULTS
  Twenty-nine patients (S-FCSEMS: 18, N-FCSEMS: 11) were included. Stent placement was technically successful in 28/29 (96.6 %) patients; stent removal was successful in 26/27 (96.2 %). Two patients with N-FCSEMS were excluded due to unsuccessful placement and withdrawal of consent for stent removal, respectively. Stent migration into the duodenum (distal migration) was observed in 9/18 (50 %) in the S-FCSEMS group compared to 0/9 in the N-FCSEMS (p < 0.005). FCSEMS migration into the CBD (proximal migration) was found in 2/18 (11 %, S-FCSEMS) versus 2/9 (22 %, N-FCSEMS, p = 0.514). A foreshortening of the N-FCSEMS occurred in 3/9 patients (33 %) compared to 0/18 S-FCSEMS (p = 0.08). Clinical resolution of the treated CBD-disease was observed in 5/9 (56 %, N-FCSEMS) versus 12/18 (67 %, S-FCSEMS) at the time of stent removal (p = 0.604) and in 0/9 and 10/18 (56 %) cases during follow-up, respectively (p < 0.005).
  
  
  CONCLUSIONS
  An unfixed cell structure of FCSEMS seems to prevent distal migration, but proximal migration still occurs and foreshortening of the N-FCSEMS constrains clinical outcome.
authors: Department of Internal Medicine I, Johann Wolfgang Goethe-University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany, Dirk.walter@kgu.de.
authors: Dirk
authors: D
authors: Walter
authors: Christoph
authors: C
authors: Sarrazin
authors: Jörg
authors: J
authors: Trojan
authors: Bernd
authors: B
authors: Kronenberger
authors: Jörg
authors: J
authors: Bojunga
authors: Stefan
authors: S
authors: Zeuzem
authors: Mireen
authors: M
authors: Friedrich-Rust
authors: Jörg G
authors: JG
authors: Albert
mesh_terms: D000368:Aged; D001660:Biliary Tract Diseases / Q000628:therapy*; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000295:instrumentation*; D003135:Common Bile Duct / Q000473:pathology; D003251:Constriction, Pathologic; D020878:Device Removal; D005548:Foreign-Body Migration / Q000209:etiology*; D006801:Humans; D008875:Middle Aged; D011474:Prosthesis Design; D012189:Retrospective Studies; D015607:Stents