Hydronephrosis; Obstruction, UreterTSTENTNCT05992363
Tandem Polyurethane Stents Compared to Single Silicone Stent for Malignant Ureteral Obstruction
A study testing ureteral stent\s insertion in people with Hydronephrosis; Obstruction, Ureter and Renal Failure, run by Rabin Medical Center at 2 sites in Israel.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Hydronephrosis; Obstruction, Ureter, Renal Failure, Malignancy
- What is being tested?
- ureteral stent\s insertion
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 106 participants
- Where
- 2 sitesIsrael
- Study dates
- 20 Dec 2023to Dec 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- patient with malignant ureteral obstruction
Who cannot join
- ureteral obstruction of other causes
- Language comprehension or other limitation in giving informed consent
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Israel2 sites, 2 recruiting
- Recruiting
Rabin Medical Center
Petah Tikva, 49414
Michael Frumer, MD, +972542686959, mic1039@gmail.com
- Recruiting
Sheba medical center
Ramat Gan
Ari Luder, MD, +972527812580, ariluder@yahoo.com
About this study
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:
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- Conditions
- Hydronephrosis; Obstruction, Ureter, Renal Failure, Malignancy, Ureter Obstruction, Ureter Stricture
- Being tested
- ureteral stent\s insertion
- Medical subject headings
- Hydronephrosis, Bites and Stings, Renal Insufficiency, Neoplasms, Ureteral Obstruction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ureteral stent\s insertionDevice
ureteral stent\s insertion in the operating room
| Study group | Role | What they receive |
|---|---|---|
| single silicone stent | Active comparator | patients with malignant ureteral obstruction that was treated by single large-caliber 8-12Fr silicone stent Receives: Device: ureteral stent\s insertion |
| Tandem polyurethane stents | Active comparator | patients with malignant ureteral obstruction that was treated by tandem 6 Fr Percuflex™ stents Receives: Device: ureteral stent\s insertion |
What is being measured
The primary outcome is the main question the study is designed to answer.
stent failure rate
Failure will be defined when two of the following three appear: renal colic, rise in serum creatinine, hydronephrosis
Measured: 1 year
Secondary outcomes (2)
quality of life score
using the Ureteral stent symptom questionnaire (USSQ) score
Measured: 1 year
overall survival
overall survival
Measured: 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Aug 2023
- Study start20 Dec 2023
- Primary completionDec 2026 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hydronephrosis; Obstruction, UreterStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- RCT
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 106 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Rabin Medical Center
- Sponsor type
- University, hospital or other
- Collaborators
- Sheba Medical Center
- Responsible party
- Principal investigator, Michael Frumer, Rabin Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05992363
- Sponsor's protocol ID
- 0100-23-RMC
- Acronym
- TSTENT
- Status last verified
- Jul 2025
- First submitted
- 8 Aug 2023
- Last updated
- 24 Jul 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Tandem Polyurethane Stents Compared to Single Silicone Stent for Malignant Ureteral Obstruction
- ClinicalTrials.gov ID
- NCT05992363
- Acronym / sponsor ID
- TSTENT / 0100-23-RMC
- Conditions
- Hydronephrosis; Obstruction, Ureter, Renal Failure, Malignancy, Ureter Obstruction, Ureter Stricture
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 106 participants (estimated)
- Lead sponsor
- Rabin Medical CenterUniversity, hospital or other
- Collaborators
- Sheba Medical Center
- Study start
- 20 Dec 2023 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 15 Aug 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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:
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
- 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
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- RCT
| Arm | Type | Receives |
|---|---|---|
| single silicone stent | Active comparator | Device: ureteral stent\s insertionpatients with malignant ureteral obstruction that was treated by single large-caliber 8-12Fr silicone stent |
| Tandem polyurethane stents | Active comparator | Device: ureteral stent\s insertionpatients with malignant ureteral obstruction that was treated by tandem 6 Fr Percuflex™ stents |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- patient with malignant ureteral obstruction
Key exclusion criteria (2 listed)
- ureteral obstruction of other causes
- Language comprehension or other limitation in giving informed consent
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ureteral stent\s insertionureteral stent\s insertion in the operating room | Device | Tandem polyurethane stents, single silicone stent |
Primary outcome
stent failure rate
Time frame: 1 year
Failure will be defined when two of the following three appear: renal colic, rise in serum creatinine, hydronephrosis
2 secondary outcomes
quality of life score
Time frame: 1 year
overall survival
Time frame: 1 year
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Jul 2025.
- Individual participant dataSharing planned: No
Related trials for Hydronephrosis; Obstruction, Ureter
Not yet recruiting
Safety and Efficacy of Ultrasound-Guided Percutaneous Nephrostomy in Oncology Patients
Obstructive Uropathy, Hydronephrosis
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing ureteral stent\s insertion in people with Hydronephrosis; Obstruction, Ureter and Renal Failure, run by Rabin Medical Center at 2 sites in Israel.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 24 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Israel. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
stent failure rate (time frame: 1 year). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Jul 2025.