title: Evaluation of bipolar radiofrequency ablation for occluded self-expandable metal stents in the bile duct: in vivo and in vitro study.
abstract: OBJECTIVE
  Endobiliary radiofrequency ablation (RFA) has been used to treat occluded self-expandable metal stents (SEMSs). The aim of this study was to determine the characteristics of bipolar RFA in occluded SEMSs using both in vivo and in vitro models.
  
  
  METHODS
  For the in vivo study, uncovered SEMSs were deployed in the bile ducts of three pigs; another pig was used as the control. RFA was performed at 10 W for 90 seconds. The bile duct was examined for histological changes. For the in vitro simulation of tissue ingrowth in SEMSs, RFA at 10 W for 30 seconds was performed on SEMS-occlusion polyacrylamide-gel phantoms.
  
  
  RESULTS
  The ablation depth was markedly reduced in the stented porcine bile duct. RFA of uncovered SEMS-occlusion gel phantoms resulted in early termination of RFA when the coagulated area contacted the SEMS. This phenomenon was not observed in RFA of the covered SEMS-occlusion gel phantoms.
  
  
  CONCLUSIONS
  The presence of SEMSs attenuated the effect of bipolar endobiliary RFA. Tumorous tissue outside the SEMS is unlikely to be affected.
authors.affiliation: Department of Internal Medicine, Inje University Seoul Paik Hospital, Inje University College of Medicine, Seoul, Republic of Korea.
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Yoon
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Yong-Tae
authors.initials: YT
authors.lastname: Kim
authors.affiliation: Gastrointestinal Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: Ebubekir S
authors.initials: ES
authors.lastname: Daglilar
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: Mari
authors.initials: M
authors.lastname: Mino-Kenudson
authors.affiliation: Gastrointestinal Unit, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: William R
authors.initials: WR
authors.lastname: Brugge
mesh_terms: D000818:Animals; D001650:Bile Duct Neoplasms / Q000601:surgery*; D001652:Bile Ducts / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D004195:Disease Models, Animal; D011183:Postoperative Complications; D011475:Prosthesis Failure; D012107:Research Design; D000069322:Self Expandable Metallic Stents / Q000009:adverse effects*; D013552:Swine