title: New concept of traction force applied to biliary self-expandable metallic stents.
abstract: OBJECTIVE
  Various mechanical properties of self-expandable metallic stents (SEMSs) have been reported. They can be classified into the device behavior during and after deployment. While there have been several reports on the latter, information on the former is insufficient. During deployment, the position is maintained by retracting the delivery catheter. We propose that this pulling force be called the traction force and that the magnitude of traction force is termed the traction momentum. The aim of this study was to measure these parameters in order to clarify the properties of SEMSs in terms of their deployment.
  
  
  METHODS
  The traction force, traction momentum, and shortening rate of 10 different SEMSs were measured. Traction force was measured using in-house equipment, and the shortening rate was determined by measuring the stents.
  
  
  RESULTS
  The shortening rate was closely related to the stent structure. The traction force varied between 1.5 N and 9.4 N, and the traction momentum was significantly elevated in covered and braided stents. A high traction force did not imply a high traction momentum.
  
  
  CONCLUSIONS
  A low or constant traction force and a minimal shortening rate significantly facilitated SEMS deployment to optimal positions. Traction force could be an important element for new ideal SEMS design.
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Yasuki
authors: Y
authors: Hori
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Kazuki
authors: K
authors: Hayashi
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Michihiro
authors: M
authors: Yoshida
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Itaru
authors: I
authors: Naitoh
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Takahiro
authors: T
authors: Nakazawa
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Katsuyuki
authors: K
authors: Miyabe
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Shuya
authors: S
authors: Shimizu
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Hiromu
authors: H
authors: Kondo
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Yuji
authors: Y
authors: Nishi
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Shuichiro
authors: S
authors: Umemura
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Akihisa
authors: A
authors: Kato
authors: Department of Community-based Medical Education, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Hirotaka
authors: H
authors: Ohara
authors: Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors: Takashi
authors: T
authors: Joh
mesh_terms: D001660:Biliary Tract Diseases / Q000150:complications / Q000601:surgery; D003251:Constriction, Pathologic / Q000150:complications / Q000601:surgery; D020878:Device Removal / Q000009:adverse effects / Q000379:methods; D019544:Equipment Failure Analysis / Q000379:methods; D006801:Humans; D007564:Japan; D041781:Jaundice, Obstructive / Q000209:etiology / Q000601:surgery; D055595:Mechanical Phenomena; D019919:Prosthesis Implantation / Q000009:adverse effects* / Q000379:methods; D000069322:Self Expandable Metallic Stents / Q000009:adverse effects / Q000592:standards / Q000706:statistics & numerical data