title: Evaluation of a chronic indwelling prototype mesh ureteral stent in a porcine model.
abstract: OBJECTIVE
  Ureteral stents all share one general goal, drainage, and one major drawback, irritative symptoms in the kidney and bladder. In an effort to preserve drainage while minimizing irritation, a lightweight, self-expanding mesh stent was designed. Herein, we compare the in vivo tissue reaction and flow characteristics of the mesh stent to a standard 7F double-pigtail polyurethane stent.
  
  
  METHODS
  Eight female Yucatan minipigs had bilateral stents placed: a mesh stent on one side and a standard 7F stent on the opposite side. Imaging and flow measurements were obtained in 4 pigs at 1 week and in another 4 pigs at 6 weeks. Following this procedure, the stents were removed, and the kidneys, ureters, and bladder were harvested en bloc for a blinded histopathologic analysis.
  
  
  RESULTS
  The degree of stent-related tissue reactivity was low for both stents and appeared similar for the ureter and bladder. Overall, the mesh stent resulted in a decrease in inflammation along the urinary tract at 1 week, but this result was statistically insignificant (P = 0.55). Flow rate through the mesh stent tended to be greater than for the polyurethane stent both at 1 week and at 6 weeks.
  
  
  CONCLUSIONS
  Overall, the mesh stent appeared to be well tolerated and provided for excellent flow.
authors.affiliation: Department of Surgery (Division of Urologic Surgery), Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: E O
authors.initials: EO
authors.lastname: Olweny
authors.forename: A J
authors.initials: AJ
authors.lastname: Portis
authors.forename: C P
authors.initials: CP
authors.lastname: Sundaram
authors.forename: J S
authors.initials: JS
authors.lastname: Afane
authors.forename: P A
authors.initials: PA
authors.lastname: Humphrey
authors.forename: R
authors.initials: R
authors.lastname: Ewers
authors.forename: E M
authors.initials: EM
authors.lastname: McDougall
authors.forename: R V
authors.initials: RV
authors.lastname: Clayman
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D003404:Creatinine / Q000097:blood; D004322:Drainage / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D007668:Kidney / Q000473:pathology; D007682:Kidney Pelvis / Q000000981:diagnostic imaging; D011140:Polyurethanes; D019736:Prostheses and Implants; D011859:Radiography; D015607:Stents; D013526:Surgical Mesh; D013556:Swine, Miniature; D014513:Ureter / Q000000981:diagnostic imaging / Q000473:pathology; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000473:pathology; D014556:Urine
chemical_list: D001672:Biocompatible Materials; D011140:Polyurethanes; D003404:Creatinine