Isotalo Taina, Nuutinen Juha-Pekka, Vaajanen Anu, Martikainen Paula M, Laurila Marita, Törmälä Pertti, Talja Martti, Tammela Teuvo L J
Department of Surgery, Päijät-Häme Central Hospital, Keskussairaalankatu 7, 15850 Lahti, Finland.
J Urol. 2005 Dec;174(6):2401-4. doi: 10.1097/01.ju.0000180412.53702.4a.
Biodegradable urethral stents have been in clinical use for more than 10 years. To solve the problems connected with the helical spiral configuration of the stents used to date we developed a new tubular mesh configuration and evaluated the biocompatibility properties and degradation time of 2 differently braided stents in the rabbit urethra.
The biodegradable, self-expanding stents were made of self-reinforced polylactic acid polymer blended with BaSO4 (Alfa Chem, Kings Point, New York). Two braiding patterns, namely a diamond 1/1 and a regular 2/2 + 1 (Prodesco, Perkasie, Pennsylvania), were used to produce a tubular mesh configuration. Stainless steel stents with 1/1 braiding served as controls. The stents were inserted into the posterior urethra of 36 male rabbits. The animals were sacrificed after 1 week, 1 month, 6 months or 12 months. Light microscopy and scanning electron microscopy analyses were done.
Tissue reactions to operative trauma were seen in all specimens at week 1. The changes gradually abated in the biodegradable stent groups, whereas chronic inflammatory changes and fibrosis were increasingly seen with metallic stents after 6 months. Epithelial hyperplasia increased with time for all stent types and materials. As expected, stent fragmentation started at 6 months.
Biodegradable polymers are suitable materials for braided urethral stents. However, the braided configuration of the stent with a decreased mass of material does not prevent the development of epithelial hyperplasia. The biodegradable, self-expanding, braided stents functioned well in the rabbit urethra and are suitable for clinical studies.
可生物降解尿道支架已临床应用超过10年。为解决与迄今使用的螺旋形支架相关的问题，我们开发了一种新的管状网状结构，并评估了两种不同编织方式的支架在兔尿道中的生物相容性和降解时间。
可生物降解的自膨胀支架由与硫酸钡混合的自增强聚乳酸聚合物制成（Alfa Chem，纽约州金斯角）。使用两种编织方式，即菱形1/1和规则的2/2 + 1（Prodesco，宾夕法尼亚州佩尔卡西）来制作管状网状结构。采用1/1编织的不锈钢支架作为对照。将支架插入36只雄性兔的后尿道。在1周、1个月、6个月或12个月后处死动物。进行了光学显微镜和扫描电子显微镜分析。
在第1周时，所有标本均可见对手术创伤的组织反应。在可生物降解支架组中，这些变化逐渐减轻，而在6个月后，金属支架出现了越来越多的慢性炎症变化和纤维化。所有类型和材料的支架上皮增生均随时间增加。正如预期的那样，支架破碎在6个月时开始。
可生物降解聚合物是编织尿道支架的合适材料。然而，材料质量减少的支架编织结构并不能防止上皮增生的发展。可生物降解的自膨胀编织支架在兔尿道中功能良好，适合进行临床研究。
