title: Evaluation of anti-migration properties of biliary covered self-expandable metal stents.
abstract: OBJECTIVE
  To assess anti-migration potential of six biliary covered self-expandable metal stents (C-SEMSs) by using a newly designed phantom model.
  
  
  METHODS
  In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration (RFM) was measured by a force gauge on the stent end. Radial force (RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare (ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model.
  
  
  RESULTS
  Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables (ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state.
  
  
  CONCLUSIONS
  RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Kosuke
authors: K
authors: Minaga
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Masayuki
authors: M
authors: Kitano
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Hajime
authors: H
authors: Imai
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Yogesh
authors: Y
authors: Harwani
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Kentaro
authors: K
authors: Yamao
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Ken
authors: K
authors: Kamata
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Takeshi
authors: T
authors: Miyata
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Shunsuke
authors: S
authors: Omoto
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Kumpei
authors: K
authors: Kadosaka
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Toshiharu
authors: T
authors: Sakurai
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Naoshi
authors: N
authors: Nishida
authors: Kosuke Minaga, Masayuki Kitano, Hajime Imai, Yogesh Harwani, Kentaro Yamao, Ken Kamata, Takeshi Miyata, Shunsuke Omoto, Kumpei Kadosaka, Toshiharu Sakurai, Naoshi Nishida, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama 589-8511, Japan.
authors: Masatoshi
authors: M
authors: Kudo
mesh_terms: D002779:Cholestasis / Q000628:therapy*; D005548:Foreign-Body Migration / Q000517:prevention & control; D006801:Humans; D008670:Metals; D015607:Stents; D013314:Stress, Mechanical
chemical_list: D008670:Metals
keywords: Anti-migration property; Biliary stricture; Radial force; Resistance force to migration; Self-expandable metal stent