Table 2.

Summary of the studies included and their main characteristics^a

Study	Stents compared	Hydrogel coating	D (Fr)	Length (cm)	Patients	Inclusion criteria	Exclusion criteria	Symptom evaluation	Stent removal	USSQ	Design	RoB	IF	Conclusion
Smedley (1988) [24]	Silicone Polyurethane	Unknown Unknown	NA	NA	116	All patients needing placement of a DJ stent	NA	Day of stent removal	Mean D79 (range 1–366)	No	RS	Serious	NA	Less loin discomfort and trigonal irritation with a silicone stent (but not significant).
Pryor (1991) [25]	Cook polyurethane Surgitek Silitek Cook C-Flex Van-Tec Soft	Unknown Unknown No Unknown	7	22–24	73	All patients needing placement of a DJ stent	Bilateral stents, long-term stent	D2 and D6 and 7 d after removal	D6–D30	No	PCS	Moderate	NA	No evidence of differences in SRS.
Lennon (1995) [9]	Cook polyurethane Cook Sof-Flex	Unknown Yes	6	22–26	155	DJ stent placed for ureteral calculi, SWL, and other miscellaneous endourologic interventions	NA	At day of stent removal	Mean D37 (range 7–182)	No	RCT	High	NA	SRS of renal pain, suprapubic pain, and dysuria were significantly higher in the polyurethane (firm) than in the Sof-Flex (soft) group. No differences in the presence of reflux pain, urgency, frequency, or hematuria. SRS severity was clearly greater with the firm stent.
Candela (1997) [19]	Bostonb Percuflex Bostonb Percuflex Plus	No Yes	4.8–6	NA	60	Stent for SWL, obstruction, or URS	Bilateral stents.	D7-10	D7–D10	No	RCT	High	NA	No evidence of differences in SRS.
Lee (2005) [20]	Bard Inlay Cook Endo-Sof Bostonb Contour Applied Medical Vertex Surgitek Classic	Yes Yes Yes Yes Yes	6	22–30	44 (70 included)	All patients undergoing unilateral retrograde ureteral stent placement	Untreated UTI, bladder cancer, additional transurethral procedures, spinal cord injury	D1, D3, D5 and 30 days after removal	NA	Yes	RCT	High	NA	Significantly fewer urinary symptoms with the Bard Inlay stent than the other stents on D3. The Bard Inlay stent had the most significant positive characteristics, while the Vertex and Surgitek Classic stents were associated with more significant negative characteristics.
Joshi (2005) [14]	Bostonb Percuflex Plus Bostonb Contour	Yes Yes	6	24	130	DJ-stent placed after URS and ESWL for stone disease	NCD, pregnancy, bilateral stents, long-term stent, stenting after PCNL	D7, D28, D56	D28	Yes	RCT	Some concerns	NA	No evidence of differences in SRS
El-Nahas (2006) [26]	Coloplasta silicone Bostonb Percuflex	Unknown Unknown	6–14	24–26	100	DJ stent placed after endopyelotomy, URS, laparascopic pyeloplasty, or endoureterotomy	SWL, pregnancy, pre-existing LUTS, complicated procedure	Day of stent removal	Mean D56 (range 28–112)	No	PCS	Serious	NA	Significantly more patient discomfort with the Percuflex (“hard”) stent than with the silicone (“soft”) stent.
Cadieux (2009) [29]	Bostonb Percuflex Plus Triumph triclosan-eluting stent	Yes No	NA.	NA	8	Long-term stent for cancer, strictures, or fibrosis	NA.	Day of stent removal	D90	No	SCCS	NA	Yes	Fewer symptomatic UTI's in patients with Triumph® triclosan eluting stents.
Mendez-Probst (2012) [21]	Bostonb Percuflex Plus Triumph triclosan-eluting stent	Yes No	NA.	27 (mean)	20	Patients requiring short-term stenting	NA	Day of stent removal	D 7–D15	No	RCT	High	Yes	Significantly less patient discomfort with Triumph® triclosan eluting stents.
Chow (2015) [30]	Cook Resonance Unspecified polymeric stent	No Unknown	6	20–30	42	Cancer patients with malignant ureteral obstruction	No previous polymeric stent	NA	NA	No	SCCS	NA	No	No evidence for differences on stent-related symptoms.
El-Nahas (2018) [22]	Carbothan + hydrogel coating Carbothan + silver sulfadiazine	Yes No	6	26	126	DJ stent placement after URS lithotripsy	<18 yr	Day of stent removal	Mean 3.1 ± 1.2 wk	Yes	RCT	Some concerns	No	No evidence for differences on stent-related symptoms.
Gadzhiev (2020) [27]	Cook Black silicone Rüschc polyurethane	Unknown Unknown	6	26	50	DJ stent placement for acute renal colic due to ureteral stone	<18 yr, >60 yr, active UTI, urogenital tumor	D1, D14, D28	D28	No	PCS	Moderate	Nod	Silicone stents were associated with lower body pain intensity on VASP at 2 wk before and immediately before stent removal vs polyurethane stents.
Wiseman (2020) [23]	Coloplast ImaJin Hydro Bostonb Percuflex Plus	Yes Yes	6	26	113 (141 included)	DJ stent placement after fURS for renal stones (5–25mm)	Acute colic pain, UT malformation, urogenital tumor, indwelling DJ stent, untreated UTI	D2, D7, D20 and D35	D20	Yes	RCT	Low	Yes	Silicone stents were associated with significantly less patient discomfort and better QoL compared to Percuflex. There was a 25% reduction in USSQ pain score (at D20) in favor of silicone. Urinary symptoms (relevant USSQ domain) were significantly lower in the silicone group at D2, D7, and D20, with the largest difference evident at D20.

D = diameter; RS = retrospective study; PCS = prospective cohort study; RCT = randomized controlled trial; SCCS = self-controlled case series; RSCCS = retrospective SCCS; USSQ = Ureteral Stent Symptom Questionnaire; RoB = risk of bias; DJ = double J; IF = industry funding; NA = not available; NOS = Newcastle-Ottawa Quality Assessment Scale; SWL = shockwave lithotripsy; URS = ureteroscopy; UT = urinary tract; UTI = UT infection; LUTS = lower urinary tract symptoms; NCD = noncalculus disease; fURS = flexible URS; PCNL = percutaneous nephrolithotomy; SRS = stent-related symptoms; VASP = Visual Analog Scale for Pain; QoL = quality of life.

^aPorges S.A.

^bMicrovasive, Boston Scientific.

^cTeleflex.

^dThe first author (Gadzhiev) is a paid consultant for Cook Medical.