Urological diseases such as tumours, kidney stones, or strictures in the ureter can lead to a number of health consequences, including life-threatening complications. Ureteral stents have been widely used as a valid solution to restore compromised urological function. Despite their clinical success, stents are subject to failure due to encrustation and biofilm formation, potentially leading to urinary tract infection. The current review focuses on recent advancements in ureteral stent technology, which have been reported in recent scientific journals or patents. Web of Science and Google Scholar have been used as a search engine to perform this review, using the keywords “Ureteral + Stent + Design”, “Ureteral + Stent + Material + Coating”, “Ureteric + Stent” and “Ureteral + Stent”. A significant proportion of technological developments has focused on innovating the stent design to overcome migration and urinary reflux, as well as investigating novel materials and coatings to prevent biofilm formation, such as poly(N,N-dimethylacrylamide) (PDMMA) and swellable polyethylene glycol diacrylate (PEGDA). Biodegradable ureteral stents (BUS) have also emerged as a new generation of endourological devices, overcoming the “forgotten stent syndrome” and reducing healthcare costs. Moreover, efforts have been made to develop pre-clinical test methods, both experimental and computational, which could be employed as a screening platform to inform the design of novel stent technologies.

Role of double-balloon enteroscopy in malignant small bowel tumors

Objective: The aim was to assess a new biodegradable and antireflux intraureteral stent (BraidStent ^® ) design in a swine model after ureteral laparoscopic operation. Materials and Methods: 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. Results: 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. Conclusions: 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.

Purpose: The aim of this study is to validate a training model that combines the use of nonbiologic and biologic simulators as well as live porcine animal model in endoscopic retrograde intrarenal surgery (RIRS). Materials and Methods: A total of 60 urologists took part in this study, and the activity lasted for 2 days. The training model was divided into three modules: Module-I, related to the acquisition of basic theoretical knowledge; Module-II, consisting of an internship with bench models; and Module III, in which animal models were used. First, trainees practiced with animals without using a lesion model (placement of an ureteral access sheath under fluoroscopic guidance and flexible ureterorenoscopy). Afterward, they practiced on a porcine animal model of bilateral renal lithiasis. Performance was measured using a validated global rating score and RIRS checklist score. Face and content validation as well as constructive validation provided by trainees in front of 15 experts were performed during the practice. Results: Face and content validations were satisfactory. “Individual” constructive validity showed statistical significance between the first and the last time that trainees practiced on an animal model. Statistical significance was also found between trainees and expert scores. There were 73.4% of trainees who increased their skills by more than 40%. Conclusion: This RIRS training model allows for the acquisition of technical knowledge and skills as face, content, and constructive validation show. A structured use of nonbiologic, biologic, and animal model simulators allows the increase of RIRS skills.