Table 3.

Summary of most commonly used designs for ureteral stents to date

Innovations in design	Key comments by manufacturer or reported in a scientific publication	Commercial example or method of reported study
Double-J	Decreasing migration of stent both proximally and distally. This design is employed in most of the ureteral stents currently on the market [28]	In-vivo human patient
Double-J 3D	Believed to provide a better proximal and distal retention	Silicon Figure Four (SFF) (Bard®, USA)
Loop	Believed to provide a 69% volume reduction in the amount of material inside bladder, and better patient comfort	Polaris™ Loop ureteral stent (Boston® Scientific, USA)
Mesh	Less frequency of upper urinary tract inflammation, but more difficult to place compared to standard unmeshed ureteral stents [34]	In-vivo study on pig model
Expandable	This design is believed to provide a higher intra-luminal flow, and ease of insertion and retrieval	Allium® Ureteral Stent (Allium Medical Solutions®, Israel)
Magnetic- tip	Allowing more effective retrieval due to the presence of magnetic material (stainless steel bead) at the distal end of the stent	Magnetic Black- Star (Urovision, Germany)
String	The extraction string is designed to be attached to the stent to facilitate removal [35]	In-vivo human patient study
Coil- Reinforced	It allows efficient drainage because of the larger lumen, it reduces kinking and buckling, and has high compressive resistance [36]	Silhouette® stent (Applied Medical, USA)
Basket	Its ability to widen laterally upon an activation force improves passageway for small stones and stops bigger stones’ migration through ureter	Ureteral Stone Sweeper® (Fossa® Medical, USA)
Spiral Cut	This type includes having the standard solid lumen of the ureteral stent at the distal and proximal region and spiral cut lumen through the rest of the stent. The stent is claimed to result in fewer upper tract symptoms [30]	In-vivo pig model study
Linearly Expandable	A design in which the stent has got spiral wire spring sandwiched between inner and outer lining of the stent wall to maintain urine flow in the presence of an obstruction [32]	In-vitro study
Helical	Side holes that emerge from the main body of the stent, direct the flow into the lumen thanks to the hole projecting out of the stent lumen and therefore potentially results in potrntially better drainage of the urine and passage of small stones [33]	In-silico study
Grooved	Specifically designed for patients treated with lithotripsy, enabling stone fragments to travel efficiently along the ureter [29, 31]	Towers Peripheral Ureteral Stent (Cook® Medical, USA)