title: Evaluation of the anti-migration effect of barbed prostatic stents: in vitro study in urethra-mimicking bovine pericardium phantoms.
abstract: OBJECTIVE
  This study was designed to compare the migration rates of covered stents with eight, four, and zero barbs in urethra-mimicking bovine pericardium models.
  
  
  METHODS
  Three types of polytetrafluoroethylene-covered retrievable self-expandable prostatic stents, with eight, four, and zero barbs, were tested in bovine pericardium models, consisting of normal saline-filled acrylic containers with tubes at both ends and a replica of the human urethra. The barbs were 2 mm in length and projected 60° toward the urinary bladder. The anti-migration force (AMF) and resistance force against stent removal (RFSR) were measured by an automatic push-pull gauge system at a fixed rate (2 mm/s).
  
  
  RESULTS
  Significant differences in AMF among the three stent types were detected (P < 0.001). Median AMF was far greater for eight-barbed than for four-barbed stents (11.96 vs. 7.55 N, P = 0.003). For stent removal, the difference between 4- and 8-barbed stents were not significant in median static (5.54 vs. 6.08 N, P = 0.15) or sliding (prostatic urethra, 5.32 vs. 5.59 N, P = 0.65; membranous urethra, 7.78 vs. 8.57 N, P = 0.364) RFSR. No perforations or scratched traces were observed during removal of these stents.
  
  
  CONCLUSIONS
  The inclusion of eight barbs projecting 60° toward the urinary bladder were not only effective against stent migration in this model but suggests that these stents may be suitable for the treatment of prostatic urethral strictures without severely irritating the tissue. However, whether these results translate into living urethral tissue is unclear, necessitating further studies.
authors: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnap 2-dong, Songpa-gu, Seoul, 138-736, Republic of Korea. hankyu1324@empas.com
authors: Han Kyu
authors: HK
authors: Na
authors: Ho-Young
authors: HY
authors: Song
authors: Jin Hyoung
authors: JH
authors: Kim
authors: Deok Ho
authors: DH
authors: Nam
authors: Jung-Hoon
authors: JH
authors: Park
authors: In Gab
authors: IG
authors: Jeong
authors: Choung-Soo
authors: CS
authors: Kim
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D020878:Device Removal; D019544:Equipment Failure Analysis; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D023421:Models, Animal; D010496:Pericardium; D019047:Phantoms, Imaging; D011138:Polytetrafluoroethylene / Q000737:chemistry; D011467:Prostate / Q000601:surgery; D011470:Prostatic Hyperplasia / Q000601:surgery; D011474:Prosthesis Design / Q000379:methods*; D011475:Prosthesis Failure; D019919:Prosthesis Implantation / Q000379:methods; D015607:Stents / Q000145:classification*; D013718:Tensile Strength; D014525:Urethral Stricture / Q000601:surgery*
chemical_list: D011138:Polytetrafluoroethylene