新型生物降解材料输尿管支架的动物实验研究

Evaluation of a New Biodegradable Ureteral Stent:An Experimental Study

探讨生物降解材料丙交酯/乙交酯共聚物(PLGA80:20)输尿管内支架的可行性,以16只家犬为实验动物,一侧输尿管施以离断吻合术,将PLGA支架管植于输尿管吻合局部支撑引流,分别于术后2、4、6、8及12周行静脉肾盂分泌造影检查,并取术侧输尿管行组织病理学分析。得到以下结果(1)10只实验动物术后支架管引流效果良好,支架管(6-8)周完全降解,术后肾盂分泌造影检查显示术侧肾盂、输尿管形态正常,无显影延迟;输尿管病理学改变轻微,主要镜下改变为移行上皮增生和固有层增厚。(2)3只实验动物术后早期支架管引流效果良好,(6-8)周时一度出现术侧肾盂及中上段输尿管扩张积水、显影延迟,在术后12周缓解;输尿管病理学改变轻微。(3)2只实验动物术后早期即出现支架管移位,最终输尿管吻合处不同程度狭窄;解剖术区输尿管粘连,管腔变窄,管壁增厚;组织病理学检查发现输尿管全层炎症反应严重。(4)1只实验动物术侧肾盂输尿管始终不显影;解剖发现输尿管吻合口尿外渗,周围形成尿性囊肿。证明PLGA材料支架管生物相容性良好,降解时间适宜,尿液内引流效果尚可,但有关支架管的外型设计、固定方式等尚需进一步研究和改进。

To investigate the feasibility of a new biodegradable ureteral stent made of L-lactide-glycolic acid copolymer 80： 20（ PLGA 80： 20）, 16 dogs served as experimental animals. Ureteral stent of PLGA 80：20 were inserted in situ into the left ureters which were transected at the mid level. Then the ureters were routinely anastomosed. Intravenous pyelography（IVP） was taken 2,4,6,8 and 12 weeks postoperatively. Histological study was taken after the ureters surrounding the stent were taken out 12 weeks postoperatively. Laboratory results are as fallows. （ 1 ） The PLGA stent was degraded completely within 12 weeks post implantation. Perfect drainage effect was found in 10 dogs ： there were no significant changes in IVP postoperative. Histological changes of ureters were mild, only transitional epithelium hyperplasia and thickening of lamina propria were found during histological analysis. （2） Hydronephrosis and imaging delay of the operated ureters were observed in 3 dogs during IVP 6--8 weeks postoperatively. This conditions were improved 12 weeks postoperatively. Histological changes of these ureters were also mild. （3） Dislocation of stent was found in 2 dogs in early stage, and resulted in ureteral stegnosis as well as hydronephrosis at last. Histological analysis showed severe inflammatory reaction in the wall of these ureters. （4）Nonvisulization of the operated ureter was identified in 1 dog, dissection discovered urinous infiltration of anastomotic stoma and urinoma surrounding the ureter. It is conclued that the biodegradable material PLGA has good biocompatibility and appropriate biodegradation characteristic, and showed perfect drainage effect. Still, much work was needed to do to improve the design and fixation of ureteral stents.