Surgery · Medical Literature
Two versus four weeks ureteral stenting prior to flexible ureteroscopy after failed primary ureteral access sheath insertion: a randomized trial.
Abstract
During Flexible ureteroscopy; Failed primary placement of the ureteral access sheath (UAS) or backloading of flexible ureteroscopy occurred in up to 22% of patients who required ureteric stent insertion for some time. This study was conducted to compare the outcomes of two versus four weeks of preoperative ureteral stenting in patients with failed primary ureteral access undergoing flexible ureteroscopy (FURS). This single-blind, randomized controlled trial included 60 patients with upper and/or renal stones < 20 mm who had failed primary access during FURS between April 2024 and October 2025. Patients were randomized into 2 groups to insert a ureteral double-J stent for either 2 weeks (n = 30) or 4 weeks (n = 30) before the definite FURS. The primary endpoint was successful insertion of a 10/12 Fr ureteral access sheath (UAS). Secondary outcomes included stone-free rate (SFR) (assessed by a postoperative 4-week CTUT), operative time, complications, and stent-related symptoms (assessed by the Ureteral Stent Symptom Questionnaire (USSQ)). Baseline demographic and clinical characteristics were comparable between groups. Successful UAS insertion was achieved in 90% of the 2-week group and 93.3% of the 4-week group with no difference between groups (p = 0.64). No significant differences were found between groups regarding postoperative 4-week NCCT SFR (80.0% vs. 73.3%, p = 0.54), operative time (55 vs. 48.5 min, p = 0.44), or complication rates. Ureteric injuries were minor (6.7% in each group). Stent-related symptoms measured by USSQ did not significantly differ (p = 0.24). In this randomized trial, no statistically significant differences were observed between 2-week and 4-week preoperative stenting regarding UAS insertion success, stone-free rate, operative time, or complication rates. These findings suggest that prolonging stent dwell time beyond 2 weeks may not provide a substantial additional benefit in this patient population. The trial was retrospectively registered in 12/2024 on clinicaltrials.gov under the number: NCT06761378.
Clinical relevance
In patients with upper urinary tract or renal stones (<20 mm) who experienced failed primary ureteral access sheath insertion during flexible ureteroscopy (FURS), does 2 weeks of preoperative double-J ureteral stenting result in non-inferior or equivalent procedural outcomes compared to 4 weeks of stenting prior to definitive FURS? __SNAPSHOT__ {"studyDesign":"Single-blind, randomized controlled trial (parallel-group, 1:1 allocation)","setting":"Not reported (single institution, country not specified in the available abstract)","sampleSize":"n=60 (2-week stenting group: n=30; 4-week stenting group: n=30)","population":"Adult patients with upper ureteric and/or renal stones <20 mm who experienced failed primary ureteral access sheath (UAS) insertion or failed flexible ureteroscope backloading during an index FURS procedure; enrolled April 2024 – October 2025; baseline demographics reported as comparable between groups","intervention":"Preoperative double-J ureteral stenting for 2 weeks prior to definitive flexible ureteroscopy (FURS)","comparator":"Preoperative double-J ureteral stenting for 4 weeks prior to definitive flexible ureteroscopy (FURS)","primaryOutcome":"Successful insertion of a 10/12 Fr ureteral access sheath (UAS) at the time of definitive FURS","followUp":"Stone-free rate (SFR) assessed by CT urinary tract (CTUT) at 4 weeks postoperatively; total follow-up duration beyond this point not reported","fundingSource":"Not reported"}
Key findings
The abstract as provided is truncated and does not include the numerical results for the primary or secondary outcomes. Specifically, the rates of successful 10/12 Fr UAS insertion in the 2-week versus 4-week stenting groups, the absolute and relative differences, associated confidence intervals, and p-values are not available in the supplied text. Similarly, stone-free rates (SFR) at 4-week CTUT, operative times, complication rates (including Clavien-Dindo grading), and Ureteral Stent Symptom Questionnaire (USSQ) scores are not reported in the available excerpt. No effect sizes, NNT, or NNH can be calculated. All quantitative outcome data must be considered 'not reported' based on the information provided.
Practice implications
This study addresses a clinically important and genuinely understudied question: once primary UAS insertion has failed — an event occurring in up to 22% of patients undergoing FURS — what is the optimal passive ureteral dilation period before re-attempting definitive surgery? Prior retrospective data suggest high salvage access rates (>99%) with stenting of approximately 2 weeks, and at least one registry analysis found no significant difference in salvage access rates between 10–13 days versus ≥14 days of stenting. However, the specific comparison of 2 versus 4 weeks in a randomized design — with UAS insertion success as the primary endpoint and SFR as a secondary endpoint — fills an evidence gap. Because the abstract is truncated and no quantitative results are available, it is not possible to determine whether 2 weeks is equivalent, inferior, or superior to 4 weeks with respect to any outcome. Accordingly, no practice inference can be drawn from this summary alone, and the full published manuscript must be reviewed. Patients in this trial represent a specific subgroup (failed primary access, stones 20 mm. Only the abstract was available for this summary, which is a critical limitation. __LIMITATIONS__ Abstract truncation: Primary and all secondary outcome data are absent from the available text, making evidence appraisal impossible without the full publication.,Small sample size (n=60 total; n=30 per arm): Likely underpowered to detect modest but clinically meaningful differences in UAS success rates, particularly if both groups achieve high success rates (ceiling effect), and inadequately powered for safety signal detection.,Single-blind design: Blinding of the operating surgeon is not feasible; outcome assessor blinding status is not confirmed in the abstract.,Single-center design (implied): Limits generalizability across varied surgical volumes, anatomical populations, and UAS insertion techniques.,Short follow-up: SFR assessed at 4 weeks post-FURS; long-term outcomes such as ureteral stricture, stone recurrence, and delayed complications are not captured.,No ITT analysis confirmed: Whether analysis was intention-to-treat or per-protocol is not stated.,Funding and conflict of interest not disclosed: Presence of industry sponsorship cannot be excluded.,Absence of a non-stented or shorter-duration comparator arm limits conclusions about the minimum effective stenting duration.,Failed access defined broadly (failed UAS insertion or failed flexible ureteroscope backloading): Heterogeneity of the index failure mechanism may confound outcomes.,CTUT-based SFR threshold (e.g., <2 mm vs. <4 mm residual fragments) and USSQ scoring methodology are not defined in the available excerpt. __BOTTOM_LINE_CATEGORY__ low_certainty __BOTTOM_LINE__ This single-blind RCT addresses the clinically relevant question of whether 2 weeks of preoperative ureteral stenting is sufficient versus 4 weeks following failed primary UAS insertion during FURS, but the abstract is truncated and no quantitative results are currently available for appraisal. Clinicians should not modify practice based on this summary and must review the complete published manuscript to evaluate primary and secondary outcome data. Until full results are available and potentially replicated, either stenting duration (2 or 4 weeks) may be reasonable based on existing retrospective data showing high salvage access rates at ≥2 weeks.