Biocompatibility testing of a new bioabsorbable X-ray positive SR-PLA 96/4urethral stent

Purpose: Recently a first X-ray-positive bioabsorbable urethral stent was d eveloped by our group. The stent is made from self-reinforced poly-l,D-lact ic acid (SR-PLA 96/4) blended with barium sulfate. The aim of this study wa s to evaluate the biocompatibility properties of the new stent materials. Materials and Methods: Rods made from pure SR-PLA 96/4 and SR-PLA 96/4 blen ded with barium sulfate were inserted into the dorsal muscles of a rabbit. Rods made from latex and silicone were used as positive and negative contro ls. To evaluate the long-term effect of BASO(4) after the bioabsorption of the polymer, fast degrading SR-PGA (self-reinforced polyglycolic acid) and SR-PLA + BASO(4) rods were used as controls. Urethral stents made from SR-P LA 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 w ere sacrificed after 1 week, 1 month or 6 months. Results: In the muscle implantation samples acute tissue reactions due to o perative trauma were seen in all specimens at 1 week. After 6 months chroni c inflammatory changes and foreign body reaction were seen only in the posi tive controls. The stent worked well in the rabbit urethra, its biocompatib ility was good and there was less encrustation than in the metal stents. Conclusions: This first X-ray-posit;ive bioabsorbable urethral stent showed no toxic tissue effects.