title: Biocompatibility testing of a new bioabsorbable X-ray positive SR-PLA 96/4 urethral stent.
abstract: OBJECTIVE
  Recently a first X-ray-positive bioabsorbable urethral stent was developed by our group. The stent is made from self-reinforced poly-L,D-lactic acid (SR-PLA 96/4) blended with barium sulfate. The aim of this study was to evaluate the biocompatibility properties of the new stent materials.
  
  
  METHODS
  Rods made from pure SR-PLA 96/4 and SR-PLA 96/4 blended with barium sulfate were inserted into the dorsal muscles of a rabbit. Rods made from latex and silicone were used as positive and negative controls. To evaluate the long-term effect of BASO4 after the bioabsorption of the polymer, fast degrading SR-PGA (self-reinforced polyglycolic acid) and SR-PLA + BASO4 rods were used as controls. Urethral stents made from SR-PLA 96/4 and X-ray-positive SR-PLA 96/4 stents were inserted cystoscopically into the rabbit urethra. Metal stents were used as controls. The animals were sacrificed after 1 week, 1 month or 6 months.
  
  
  RESULTS
  In the muscle implantation samples acute tissue reactions due to operative trauma were seen in all specimens at 1 week. After 6 months chronic inflammatory changes and foreign body reaction were seen only in the positive controls. The stent worked well in the rabbit urethra, its biocompatibility was good and there was less encrustation than in the metal stents.
  
  
  CONCLUSIONS
  This first X-ray-positive bioabsorbable urethral stent showed no toxic tissue effects.
authors.affiliation: Division of Urology, Tampere University Hospital, and Tampere University of Technology, Lahti, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Isotalo
authors.forename: E
authors.initials: E
authors.lastname: Alarakkola
authors.forename: M
authors.initials: M
authors.lastname: Talja
authors.forename: T L
authors.initials: TL
authors.lastname: Tammela
authors.forename: T
authors.initials: T
authors.lastname: Välimaa
authors.forename: P
authors.initials: P
authors.lastname: Törmälä
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials; D019344:Lactic Acid; D008297:Male; D008422:Materials Testing; D011091:Polyesters; D011108:Polymers; D011817:Rabbits; D015607:Stents; D014521:Urethra; D014965:X-Rays
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)