title: Braided thin-walled biodegradable ureteral stent: preliminary evaluation in a canine model.
abstract: OBJECTIVE
  To evaluate a novel designed degradable ureteral stent.
  
  
  METHODS
  A total of 24 male Beagles, each with bilateral stents implanted (a biodegradable ureteral 4.5-Fr stent and a standard 4-Fr biostable stent) were divided into four groups. Intravenous pyelography, B-mode ultrasonography, and blood and urine tests were carried out before the procedure (0 weeks), and at 1-, 2-, 3- and 4-week intervals. Meanwhile, the mechanical characteristics of stents were tested, and scanning electron microscopy images of the biodegradable braided stents were obtained at different time-points postoperatively. In addition, histopathological changes were compared between the two different stents.
  
  
  RESULTS
  All biodegradable braided stents began degrading at 1 week, and had completely degraded by 4 weeks. Hydronephrosis was equivalent during the first 2 weeks, but less with the biodegradable stents than with the control biostable stents at 3 and 4 weeks. Preoperative and postoperative blood and urine results were similar. The mechanical properties of the biodegradable stents were better than conventional biostable stents. Scanning electron microscopy images obtained at different weekly intervals showed that stents degraded in a predictable fashion. Histological testing of the urinary tract showed that the stent-related tissue reactivity of the two different stents were similar.
  
  
  CONCLUSIONS
  Our novel braided thin-walled biodegradable stents provide temporary renal drainage as good as commercially available biostable stents. They also have good biocompatibility and physical characteristics. Therefore, they might have clinical application.
authors.affiliation: Department of Urology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Ming Qing
authors.initials: MQ
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Zou
authors.forename: Yi Chen
authors.initials: YC
authors.lastname: Huang
authors.forename: Ya Feng
authors.initials: YF
authors.lastname: Shang
authors.forename: Gang Gang
authors.initials: GG
authors.lastname: Yang
authors.forename: Wen Zu
authors.initials: WZ
authors.lastname: Wang
authors.forename: Jun Mei
authors.initials: JM
authors.lastname: Zhou
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Xie
mesh_terms: D020341:Absorbable Implants / Q000009:adverse effects*; D000818:Animals; D001466:Barium Sulfate; D004285:Dogs; D006869:Hydronephrosis / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008855:Microscopy, Electron, Scanning; D010865:Pilot Projects; D011474:Prosthesis Design; D011859:Radiography; D011897:Random Allocation; D015607:Stents / Q000009:adverse effects*; D014513:Ureter / Q000000981:diagnostic imaging / Q000601:surgery*
chemical_list: D001466:Barium Sulfate
keywords: canine; polymers; stents; ureter