Hello and welcome to the Stent News, a newsletter where we discuss every three months the most recent and relevant studies in stone disease.

Suscribe now

Dear colleagues and stent enthusiasts,

We are back with the autumn edition of our newsletter. As always, I have selected three recent scientific papers, all published in recent months, to bring you up to date on topics related to ureteral stents.

First, I feature a pilot study suggesting that multimodal preoperative education is a plausible and safe strategy to reduce pain and emergency department visits following ureteral stent placement. 

The second paper demonstrates that 4.7 Fr ureteral stents significantly improve tolerability and quality of life compared to 6 Fr stents following uncomplicated ureterorenoscopy. 

Finally, a systematic review suggests that metallic ureteral stents may offer longer functional duration and reduce the need for periodic exchanges compared to polymeric stents in chronic malignant obstruction, while maintaining a comparable safety and tolerability profile.

I hope you find them interesting!

3'

In a prospective, exploratory randomized controlled trial, the authors evaluated the impact of structured, multimodal preoperative patient education on postoperative pain and unplanned emergency department visits following ureteral stent placement. Although this topic has been previously addressed in the scientific literature, it highlights the importance of this strategy as a simple, safe approach to reducing pain and anxiety in patients with a ureteral stent.

The study evaluates two groups: the intervention group received an in-depth, multimodal educational session (an extended verbal explanation, a short video, and handling of a sample stent), while the control group received standard counseling (a brief explanation and a pamphlet). The study parameters included the Visual Analog Scale (VAS) pain score on postoperative day 1, as well as unplanned emergency department visits within 30 days.

The intervention group demonstrated a lower median VAS score and fewer unplanned emergency department visits (5.3% vs. 24.1%). Due to the small sample size, none of the primary study outcomes reached statistical significance. Complication rates were low and similar between both groups. These preliminary, hypothesis-generating findings suggest that enhanced preoperative education is a low-cost, clinically plausible strategy for reducing stent-related pain and unplanned healthcare utilization, but they do not establish efficacy; confirmation in an adequately powered multicenter trial is required before recommending any change in clinical practice. Unfortunately, as noted, this study suffers from a lack of statistical power. Another weakness inherent to this type of study is the placebo effect, as patients in the intervention group received more time, attention, and empathy from the healthcare team.

3'

In an excellent single-center, double-blind (patient- and evaluator-blinded) randomized controlled trial, the authors evaluated the clinical tolerability of 4.7 Fr versus standard 6 Fr double-J ureteral stents. A total of 119 participants were analyzed following elective flexible or rigid ureterorenoscopy for uncomplicated primary urolithiasis. To minimize confounding and selection bias, strict exclusion criteria were applied: pre-stented status, bilateral stenting, stents crossing the bladder midline, impacted calculi, severe ureteral edema, vaginal vault prolapse, concurrent alpha-blocker/anticholinergic/analgesic therapy, active UTI, neurogenic bladder, urological malignancy, or intraoperative complications. This rigorous patient selection significantly enhances the internal validity of the trial. Postoperative morbidity was measured at 3 weeks using the International Prostate Symptom Score (IPSS) and the Ureteral Stent Symptom Questionnaire (USSQ), with complications graded according to the Modified Clavien-Dindo Classification.

At 3 weeks, mean IPSS scores were comparable between groups. However, patients in the 4.7 Fr cohort reported significantly better overall USSQ scores than the 6 Fr group. Overall, 84% of participants remained complication-free, with similar safety rates between the 4.7 Fr (82.5%) and 6 Fr (85.5%) cohorts. Notably, Clavien-Dindo Grade 3 complications were higher in the 4.7 Fr group (8.8% vs. 3.2%), primarily driven by early stent displacement, although this difference did not reach statistical significance.

These findings support an evolving paradigm in Endourology. While 6 Fr stents have historically served as the standard due to structural stability and low displacement rates, hydrodynamic evidence indicates that urinary transport occurs predominantly extraluminally around the stent rather than intraluminally. Smaller 4.7 Fr stents provide greater clearance within the ureteral lumen, substantially decreasing urothelial shear stress and mechanical irritation without compromising drainage or surgical success.

In summary, 4.7 Fr ureteral stents offer significantly improved patient tolerability and health-related quality of life following uncomplicated intracorporeal lithotripsy. This trial provides clear clinical evidence favoring smaller-caliber stenting to mitigate stent-related symptoms, while cautioning clinicians regarding a potential propensity for stent migration, particularly in markedly dilated renal pelvis.

2'

The authors conducted a systematic review identifying comparative studies on metallic versus polymeric ureteral stents in adults presenting with chronic malignant ureteral obstruction. Given the absence of randomised trials and the heterogeneity of existing comparative data, the relative benefits of metallic versus polymeric ureteric stents in chronic MUO remain unclear. As this topic is a classic and notoriously difficult problem in urological practice, this paper provides valuable clinical insight. Four studies reported stent failure outcomes. Metallic stents demonstrated a trend toward a lower risk of stent failure compared with polymeric stents; however, this did not reach statistical significance. Only two studies reported stent migration rates. One study observed no migration events in either group, while the other reported three migration events among polymeric stents and none among metallic stents. Stent encrustation was reported in only one study, which documented four encrustation events in polymeric stents and none in metallic stents. There was no significant difference in symptom burden between patients receiving metallic versus polymeric stents. Three studies reported the frequency of stent exchanges, with polymeric stents requiring approximately 3 to 7 exchanges per year compared with 1 to 2.2 exchanges per year for metallic stents.

In summary, these findings suggest that metallic ureteral stents provide prolonged functional dwell times and substantially reduce the burden of repeated surgical interventions, while maintaining a safety and tolerability profile comparable to standard polymeric stents. Metallic stenting represents a highly viable strategy in appropriately selected patients with chronic MUO, particularly those for whom frequent reinterventions carry prohibitive morbidity, patients with limited life expectancy, or cases with documented failure of  polymeric stents.