Experimental Assessment of New Generation of Ureteral Stents: Biodegradable and Antireflux Properties

The aim was to assess a new biodegradable and antireflux intraureteral stent (BraidStent^®) design in a swine model after ureteral laparoscopic operation. A total of 24 female pigs underwent initial endoscopic, nephrosonographic, and contrast fluoroscopy assessment of the urinary tract. Afterward, unilateral ureteropelvic junction obstruction was performed by laparoscopic approach. Six weeks later, the animals underwent laparoscopic Anderson-Hynes pyeloplasty, and were randomly assigned to Group-I, in which a double-pigtail ureteral stent was inserted for 6 weeks, or Group-II, in which a BraidStent^®, a biodegradable intraureteral stent design, was placed. Follow-up assessments were performed at 3 and 6 weeks and 5 months. In terms of therapeutic success, complete resolution was observed in 91.6% of Group-I animals and 88.8% in Group-II. No evidence of vesicoureteral reflux (VUR) was observed in Group-II animals and statistical significance in VUR and ureteral orifice damage were observed between groups. BraidStent^® degradation occurred in a controlled manner between 3 and 6 weeks, without obstructive fragments. Distal ureteral peristalsis was maintained in 66.6% and 83.3% in Group-II at 3 and 6 weeks of follow-up, respectively. In Group-II, the positive bacteriuria rate was 41.6% and the migration rate 25%. Pathological assessment showed a significant improvement in ureteral healing in Group-II vs Group-I. The results of this comparative study in a porcine model indicate that the intraureteral BraidStent performed similarly to conventional ureteral stents. It avoids complete ureteral length intubation, the adverse effects associated with conventional ureteral stents, and maintains a high level of distal ureteral peristalsis. Moreover, the BraidStent^® exhibited a predictable and controlled degradation rate and did not cause any obstructive fragments. However, further studies are needed to improve the anchoring system and reduce the risk of bacterial colonization.