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RecruitingNCT05992363TSTENTUpdated Jul 24, 2025

Tandem Polyurethane Stents Compared to Single Silicone Stent for Malignant Ureteral Obstruction

An interventional study of ureteral stent\s insertion in Hydronephrosis; Obstruction, Ureter, Renal Failure and Malignancy, sponsored by Rabin Medical Center. Recruiting at 2 sites in Israel. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-07-24.

Sponsored by Rabin Medical Center · Not applicable, Interventional, and Treatment

From the registry’s dates

  • Started Dec 2023; still recruiting 2 years 10 months later.
Phase
Not applicable
Study type
Interventional
Enrollment
106
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

Malignant ureteral obstruction (MUO) is an extrinsic ureteral obstruction caused by malignant diseases. This study aim to compare tandem 6 Fr Percuflex™ stents and single large-caliber 8Fr silicone stent in patients with MUO. The primary endpoint is stent failure rate. The secondary endpoints are patient comfort, quality of life and overall survival.

Read the detailed description

Malignant ureteral obstruction (MUO) is an extrinsic ureteral obstruction caused by malignant diseases. MUO may induce renal failure, which would be a barrier to several therapies including chemotherapy. Indwelling double-pigtail polymeric ureteral stent is a common method to release renal obstruction, but does not necessarily guarantee renal decompression as most studies reported stent failure with a mean of 30% at a mean time of three months [1-3]. Various endoscopic strategies have been proposed to increase time to failure, including tandem polymeric stents, metallic spiral coil stent, self-expanding Nitinol stent and polymeric stents with different lumen diameter and stiffness [4-7]. However, heterogeneity of MUO, low number of patients, unspecified polymer type, retrospective studies and the lack of a standard method to assess stent failure limit robust comparative analysis.

Tandem ureteral stents (TUS) technique uses two polymeric ureteral stents passed simultaneously to better withstand the presumed compressive forces that overcome conventional single stent. This method offers an additional parallel lumen and allows more extraluminal flow between the two stents [6].

In a study on TUS in 39 renal units with MUO, two 6 Fr stents were inserted. Stent failure, defined by flank pain with increasing creatinine level or worsening hydronephrosis during 3 months after stents insertion, was occurred in 4% of cases [7]. This low failure rate compares favorably with the reported rates with single 6Fr polymeric stent or metallic stent. However, stents irritation, defined by profound lower urinary tract symptoms or renal colic in the absence of worsening hydronephrosis or infection, was reported in 29-85% of patients [7,8].

Silicon stent, which is considered biocompatible and soft, has the potential to be less irritative. In a recent systematic review, silicone stents has less stent-related symptoms in comparison to non-silicone polymers and ''hard'' stents. [9]. However, silicone has high susceptibility to compression, which in case of MUO may results in lower drainage efficacy.

This study aim to compare tandem 6 Fr Percuflex™ stents and single large-caliber 8Fr silicone stent in patients with MUO. The primary endpoint is stent failure rate. The secondary endpoints are patient comfort, quality of life and overall survival.

References:

  1. Docimo SG, Dewolf WC. High failure rate of indwelling ureteral stents in patients with extrinsic obstruction: experience at 2 institutions. J Urol. 1989;142(2 Pt 1):277-279. doi:10.1016/s0022-5347(17)38729-3
  2. Vogt B, Blanchet LH. Analysis of Ureteral Tumour Stents for Malignant Ureteral Obstruction: Towards Reshaping an Optimal Stent. Res Rep Urol. 2021;13:773-782. Published 2021 Oct 27. doi:10.2147/RRU.S334277
  3. Chung SY, Stein RJ, Landsittel D, et al. 15-year experience with the management of extrinsic ureteral obstruction with indwelling ureteral stents. J Urol. 2004;172(2):592-595. doi:10.1097/01.ju.0000130510.28768.f5
  4. Patel C, Loughran D, Jones R, Abdulmajed M, Shergill I. The resonance® metallic ureteric stent in the treatment of chronic ureteric obstruction: a safety and efficacy analysis from a contemporary clinical series. BMC Urol. 2017;17(1):16. Published 2017 Mar 10. doi:10.1186/s12894-017-0204-8
  5. Khoo CC, Ho C, Palaniappan V, et al. Single-Center Experience with Three Metallic Ureteral Stents (Allium® URS, Memokath™-051, and Resonance®) for Chronic Ureteral Obstruction. J Endourol. 2021;35(12):1829-1837. doi:10.1089/end.2021.0208
  6. Fromer DL, Shabsigh A, Benson MC, Gupta M. Simultaneous multiple double pigtail stents for malignant ureteral obstruction. Urology. 2002;59(4):594-596. doi:10.1016/s0090-4295(01)01646-7
  7. Elsamra SE, Motato H, Moreira DM, et al. Tandem ureteral stents for the decompression of malignant and benign obstructive uropathy. J Endourol. 2013;27(10):1297-1302. doi:10.1089/end.2013.0281
  8. Shvero A, Haifler M, Mahmud H, Dotan Z, Winkler H, Kleinmann N. Quality of life with tandem ureteral stents compared to percutaneous nephrostomy for malignant ureteral obstruction. Support Care Cancer. 2022;30(11):9541-9548. doi:10.1007/s00520-022-07354-2
  9. Boeykens M, Keller EX, Bosio A, et al. Impact of Ureteral Stent Material on Stent-related Symptoms: A Systematic Review of the Literature. Eur Urol Open Sci. 2022;45:108-117. Published 2022 Oct 19. doi:10.1016/j.euros.2022.09.005
02

Conditions studied

  • Hydronephrosis; Obstruction, Ureter
  • Renal Failure
  • Malignancy
  • Ureter Obstruction
  • Ureter Stricture
03

In context

Hydronephrosis

55 studies on the registry are indexed under Hydronephrosis; 9 are open to participants now.

This study's planned enrollment of 106 is close to the median of 100 across 23 interventional studies indexed under Hydronephrosis.

Browse Hydronephrosis studies →

Lead sponsor

Rabin Medical Center is the lead sponsor of 393 studies on the registry; 30 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • patient with malignant ureteral obstruction

Exclusion criteria

Exclusion Criteria:

  • ureteral obstruction of other causes
  • Language comprehension or other limitation in giving
Terms in these criteria, in plain language(1)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Triple (Participant, Investigator, Outcomes assessor)
Enrollment
106 participants (estimated)

Study arms

  • Active comparator
    single silicone stent

    patients with malignant ureteral obstruction that was treated by single large-caliber 8-12Fr silicone stent

    Device: ureteral stent\s insertion

  • Active comparator
    Tandem polyurethane stents

    patients with malignant ureteral obstruction that was treated by tandem 6 Fr Percuflex™ stents

    Device: ureteral stent\s insertion

Interventions

  • Deviceureteral stent\s insertion

    ureteral stent\\s insertion in the operating room

06

What researchers measure

Primary outcomes

  1. stent failure rate

    Failure will be defined when two of the following three appear: renal colic, rise in serum creatinine, hydronephrosis

    Time frame: 1 year

Secondary outcomes

  1. quality of life score

    using the Ureteral stent symptom questionnaire (USSQ) score

    Time frame: 1 year

  2. overall survival

    overall survival

    Time frame: 1 year

07

Study locations

2 of 2 sites recruiting
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 24, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05992363
Responsible party
Michael Frumer (Urologist, Rabin Medical Center) — Principal investigator
First posted
Aug 15, 2023
Start date
Dec 20, 2023
Primary completion
Dec 2026 (estimated)
Completion
Dec 2027 (estimated)
Last update
Jul 24, 2025

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
Yes
View the source record on ClinicalTrials.gov ↗

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