The current status and applications of ureteral stents

Ureteral strictures and obstructions are common urinary diseases in modern society, and they cause great pain to patients. A ureteral stent (US) is a minimally invasive surgical device for the relief of obstructions and drainage from the kidney to the bladder. Ureteral stents have been used clinically for over 40 years. However, ureteral stent implantation may cause some complications, such as increased urinary frequency, urgency, infection, migration, etc. Up to now, no ureteral stent with ideal properties has been used clinically. Researchers and surgeons have been working to update and develop satisfactory devices. This paper summarizes the clinical research and the advantages and disadvantages of various US materials and configurations. Ureteral stents made of traditional polymer materials are inexpensive but are prone to encrusting and low strength, weaknesses which are not ideal for drainage and support in the ureter. Ureteral stents made of metal have better mechanical strength. However, with a stent implanted in the body for a prolonged time, the surface of the stent will become covered with stones and encrustation, leading to infections and ureter obstruction again. Ureteral stents made of biodegradable material avoid the trouble of secondary removal. However, it is difficult to control the degradation time of this type of stent, and some small fragments remain in the ureter after the stent degrades. Some novel technologies, such as antibacterial, encrustation-free, coating and drug-eluting, may be good ways to improve the performance of US.