title: Silicone-covered biodegradable magnesium-stent insertion in the esophagus: a comparison with plastic stents.
abstract: BACKGROUND
  We determined the feasibility of, and tissue response to silicone-covered biodegradable magnesium- and plastic-stent insertion into the esophagus in rabbits.
  
  
  METHODS
  The mechanical compression-recovery characteristics and degradation behaviors of the magnesium stent were investigatedin vitro. A total of 45 rabbits were randomly divided into a magnesium- (n= 15) and a plastic- (n= 15) stent group, and underwent stent insertion into the lower third of the esophagus under fluoroscopic guidance; a control group (n= 15) did not undergo the intervention. Esophagography was performed at 1, 2, and 4 weeks. Five rabbits in each group were euthanized at each time point for histological examination.
  
  
  RESULTS
  Silicone-covered magnesium stents showed similar radial force to plastic stents (p> 0.05). The magnesium stents degraded rapidly in an acidic solution, but 90.2% ± 3.1% of the residual mass was maintained after a 2-week degradation in a solution with a pH of 4.0. All stent insertions were well tolerated. Magnesium stents migrated in six rabbits (one at 1 week, one at 2 weeks and four at 4 weeks), and plastic stents migrated in three rabbits (one at 2 weeks and two at 4 weeks;p> 0.05). Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was similar in both stented groups (p> 0.05), and the esophagus wall was found to be significantly thinner in the stented groups than in the control group (p< 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ from the control group (p> 0.05).
  
  
  CONCLUSIONS
  Esophageal silicone-covered magnesium stents provided reliable support for at least 2 weeks, with acceptable migration rates and without causing severe injury or tissue reaction compared with plastic stents.
authors.affiliation: Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China.
authors.forename: Yue-Qi
authors.initials: YQ
authors.lastname: Zhu
authors.affiliation: Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Yang
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, China and Nanotechnology Engineering, University of Waterloo, Ontario, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Edmonds
authors.affiliation: Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, China.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Wei
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, China.
authors.forename: Reila
authors.initials: R
authors.lastname: Zheng
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, China.
authors.forename: Ruo-Yu
authors.initials: RY
authors.lastname: Cheng
authors.affiliation: Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yi Shan Road, Shanghai, 200233, China and Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, No. 708 Renmin Rd, Suzhou, Jiangsu 215006, China.
authors.forename: Wen-Guo
authors.initials: WG
authors.lastname: Cui
authors.affiliation: Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yi Shan Road, Shanghai, 200233, China and Department of Orthopedics, The First Affiliated Hospital of Soochow University, Orthopedic Institute, Soochow University, No. 708 Renmin Rd, Suzhou, Jiangsu 215006, China.
authors.forename: Ying-Sheng
authors.initials: YS
authors.lastname: Cheng
keywords: biodegradable stent; esophagus; magnesium; tissue reaction