Prevention and treatment of symptoms associated with indwelling ureteral stents: A systematic review

Triangular prismatic JJ stent does not cause more discomfort than tubular ones: a randomised controlled trial comparison

OBJECTIVE

To compare the stent-related symptoms (SRS) of three commonly used, readily accessible ureteric JJ stents after uncomplicated flexible ureteroscopic lithotripsy (FURL), in a prospective randomised controlled single-blind parallel-group study, in order to see whether structural difference might influence SRS.

PATIENTS AND METHODS

Patients undergoing FURL were randomised into three groups: the Cook Group received conventional 6 F Cook Universa Soft JJ stents as control, the Kang Yi Bo (KYB) Group received 6 F KYB anti-reflux JJ stents, and the Urovision Group received 7 F Urovision Visiostar ESWL JJ stents. The ureteric stent symptom questionnaire (USSQ) was administered at 1 week, 4 weeks (before stent removal), and 5 weeks (one week after stent removal as baseline evaluation) after stent insertion. Both raw and baseline-adjusted USSQ domain subscores at 1 week and 4 weeks were compared.

RESULTS

A total of 146 patients were included in the analysis. The KYB Group showed significantly lower P6&7 subscore yet higher urinary symptoms score 1 week and 4 weeks after stents insertion than both Cook and Urovision, whilst the Urovision Group achieved similar scores in most domains with Cook.

CONCLUSIONS

Although the KYB anti-reflux JJ stent might prevent vesicoureteral reflux, it induces significantly stronger urinary symptoms, both at 1 week or 4 weeks after stent insertion, with or without baseline correction. Despite the unique triangular prismatic shape, the Urovision Visiostar stent does not cause heavier urinary symptoms or pain compared to the conventional cylinder shape counterparts.

A Prospective, Randomized Controlled Multicenter Trial Comparing the Bard Inlay Optima and the Cook Universa Soft Stent

OBJECTIVE

To determine if the Bard Inlay Optima with its anti-inflammatory pHreecoat stent coating had reduced stent-related symptoms at Week 1 (W1) and Week 3 (W3) post insertion compared to the Cook Universa Soft (CUS) using the validated Ureteral Stent Symptoms Questionnaire (USSQ).

METHODS

A prospective, double-blinded, randomized controlled trial was performed on patients receiving unilateral retrograde double-J stents for urolithiasis or pelviureteric junction obstruction at three public Urology services. One hundred forty patients that met inclusion criteria were randomized in a 1:1 ratio to each stent. Primary endpoints were the mean USSQ index scores for the urinary, pain, general, and sexual health domains at W1 and W3. Secondary endpoints were responses to individual USSQ questions, early stent removal, and postoperative opioid use.

RESULTS

No significant difference was found between the two stents in terms of index scores for all USSQ domains, early stent removal or postoperative opioid use. The CUS had worse symptom scores at W1 relating to self-reported urinary tract infection symptoms (3.1 ± 1.3 vs 2.6 ± 1.3, P = .05). The CUS was also associated with higher rate of representation to hospital at W1 (n = 10, 16% vs n = 1, 2%, P < .001) and W3 (n = 15, 25% vs n = 3, 5%, P < .001). This did not remain significant when adjusted to site of recruitment (W1 P = .27; W3 P = .22).

CONCLUSION

The Bard Inlay Optima's anti-inflammatory pHreecoat stent coating did not translate to any significant difference in overall postoperative symptoms across urinary, pain, general, and sexual health domains.

Comparing the effect of peri-operative antibiotic prophylaxis only with continuous low-dose antibiotic treatment on the incidence of urinary tract infection and stent related-symptoms in patients undergoing Double-J (DJ) stent insertion following transurethral lithotripsy (TUL)

PURPOSE

There are some controversial data about the peri operative use of antibiotics after double-J (DJ) insertion. This study aimed to compare the rates of urinary tract infections (UTI) and stent-related symptoms (SRSs) in patients who received only perioperative antibiotic prophylaxis and those given continuous low-dose antibiotic therapy for the entire stent-indwelling time following transurethral lithotripsy (TUL).

METHODS

In this randomized clinical trial 178 patients received intravenous antibiotic prophylaxis (ciprofloxacin 400 mg) before the TUL and then randomly divided into two groups to either receive no antibiotic treatment after procedure (group A, 90 patients) or to additionally receive a continuous low-dose antibiotic treatment with one ciprofloxacin 500 mg every 12 h for 3 days and then ciprofloxacin 250 mg once daily for the entire stent-indwelling time (group B, 88 patients). The rates of UTIs, SRSs and incidence of drug side-effects were evaluated in groups.

RESULTS

A total of 7 patients had positive urine culture [group A: 4 (4.4%) vs. group B: 3 (3.4%); P = 0.722]. Only 1 patient in group B had febrile UTI in the mean duration of indwelling stent in situ. The rate of SRSs was 92.2% and 89.8% in Group A and B, respectively, with no significant difference (P = 0.609). A total of 4 patients in Group B complained of gastrointestinal side effects of ciprofloxacin.

CONCLUSION

Continuous low-dose antibiotic treatment has no role in reducing the incidence of UTIs and SRSs during the indwelling time of ureteral stents compared with the peri-operative antibiotic prophylaxis only.

Ureteral Stent-Related Symptoms and Pharmacotherapy: A Brief Narrative Review

The purpose of this article is to review the effects of different types of pharmacotherapy on symptoms that affect the quality of a patient's life after stent insertion. A thorough Medline/PubMed nonsystematic review was conducted from 1987 to January 2023, using the terms: "pigtail" OR "ureteral stents" AND "lower urinary tracts symptoms" OR "LUTS" AND "pharmacotherapy" OR "drugs". Relevant studies conducted in humans and reported in English language were included. The available reviews and articles associating the use of drugs with stent-related symptoms (SRS) provide conflicting results. Most of them show a clear benefit of alpha blockers, particularly alfuzosin, on treating urinary SRS, and hence there is a strong recommendation for the use of alpha blockers for the treatment of SRS in the guidelines of the European Association of Urology. Anticholinergics and mirabegron have shown a significant benefit in dealing with irritative bladder symptoms. In contrast, the findings for combination therapies are contradictory, with some studies showing that combination therapy is no superior to monotherapy with regards to most of the subsets of the Ureteral Stent Symptom Questionnaire (USSQ), whereas others present a clear benefit of combination therapies, specifically silodosin and solifenacin, in treating stent-associated lower urinary tract symptoms (LUTS), in comparison with any other type of monotherapy or combination therapy. Many studies suggest that some categories of pharmacotherapy, such as alpha blockers, can alleviate SRS. However, there is conflicting evidence concerning most other types of medical treatment. Randomized trials with the largest number of patients are needed to investigate the effectiveness of novel approaches on SRS.

Does bacterial colonization influence ureteral stent-associated morbidity? A prospective study

Objective

to evaluate the effect of bacterial colonization on ureteral stent-associated morbidity.

Methods

This was a prospective study that took place between February 2019 and March 2022. We examined one hundred fifteen patients for ureteric stents application. On the same day of stent removal, the Arabic version of Ureteral Stent Symptoms Questionnaire (USSQ) was used to assess stent-associated morbidity. The stent-associated morbidity and the specificity and sensitivity of culture in the stent and midstream urine were recorded.

Results

In 15.6% of the patients stent colonization was positive; E. coli was the most common isolated organism. There was no statistically significant difference between sex, age, irrigation fluid volume and duration of operation for stent colonization. However, stent indwelling time was significantly higher in patients with stents with positive cultures. In the colonized stents, there was a statistically significant difference with regards to the total score of USSQ, pain, urinary symptoms, work performance and additional problems of USSQ. Meanwhile, there was no statistically significant difference in the general health and sexual matter.

Conclusions

stent colonization may be a contributing factor in stent-related morbidity. Stent bacterial colonization increases with the time of stent retention. Stent cultures are not needed as the same microorganisms are detected in urine cultures.

Impact of Ureteral Stent Material on Stent-related Symptoms: A Systematic Review of the Literature

Context

Ureteral stents are essential implants that are used on a daily basis. Since their invention, advances in stent design have been directed towards alleviating stent-related symptoms. It remains unclear how the material composition of the stent affects stent-related symptoms.

Objective

To review the literature and define the clinical impact of ureteral stent material on stent-related symptoms.

Evidence acquisition

A literature search of the Embase, MEDLINE (PubMed), and Web of Science databases was conducted on December 17, 2021 to collect articles comparing stent composition materials regarding stent-related symptoms. Thirteen publications met the inclusion criteria, of which only one met the high-quality requirements of the Cochrane Collaboration tool for assessing the risk of bias in randomized trials.

Evidence synthesis

Most trials, including the highest quality trial, seem to support that silicone double-J (DJ) stents reduce stent-related symptoms compared to nonsilicone DJ stents. Regarding physical properties, it seems that “soft” or “flexible” DJ stents reduce stent-related symptoms. However, since there was only one high-quality study with a low risk of bias, it is impossible to draw a definitive conclusion owing to the lack of quality data.

Conclusions

Silicone DJ stents, and by extension “soft” DJ stents, appear to reduce stent-related symptoms compared to nonsilicone polymers and “hard” DJ stents. No definitive conclusion can be drawn owing to a lack of quality evidence. Creating a standard for measuring and reporting physical stent properties should be the first step for further research.

Patient summary

A ureteral stent is a small hollow tube placed inside the ureter to help urine drain from the kidney. We reviewed the literature on the impact of stent material on stent-related symptoms. We found that silicone may reduce stent-related symptoms, but no definitive conclusion can be drawn and further studies are needed.

Incidental findings on prostate MRI: a close look at the field of view in this anatomical region

Magnetic resonance imaging (MRI) has been widely used as an advanced imaging modality to detect prostate cancer and indicate suspicious areas to guide biopsy procedures. The increasing number of prostate examinations with MRI has provided an opportunity to detect incidental lesions, and some might be very significant to elucidate patient symptoms or occult neoplastic process in the early stages. These incidental lesions might be located in the prostate gland, adjacent tissues, or organs around the prostate gland or out of the genitourinary system. The field of view of prostate MRI includes not only the prostate gland but also other critical pelvic organs in this specific anatomical region. Some of these incidental lesions might cause the same symptoms as prostate cancer and might explain the symptoms of the patient, and some might indicate early cancer stages located outside the prostate. Reporting these lesions might be life-saving by initiating early disease treatment. Awareness of the predicted locations of congenital anomalies would also be beneficial for the radiologists to mention these incidental findings.

Advances in ureteral stent technology

PURPOSE OF REVIEW

Ureteral stents are an invaluable tool for urologists but suffer from several drawbacks, including: limited durability due to stent encrustation, significant morbidity from bothersome urinary symptoms, pain and infection, risk of the forgotten stent and costly removal. This review highlights key advances in ureteral stent technology that seek to address these issues.

RECENT FINDINGS

Over the past 2 years clinical trials have brought ureteral stent technology aimed to reduce stent-associated morbidity closer to clinical application. Stent material and changes to stent design show promise in improving patient tolerability without increasing complications. Low-tech innovations such as magnetic and catheter snare removal may quickly reduce costs. Radical advances such as biodegradable stent materials remain in preclinical models but show promise for eliminating the need for stent removal.

SUMMARY

The ideal ureteral stent does not currently exist in clinical practice. This review highlights key studies that have advanced ureteral stent technology in the past 2 years.

Are All Stent Bearers Equal? Ureteral Stent Symptoms in Kidney Transplant Patients: A Case-Control Prospective Study

Purpose: The aim of this study is to conduct a prospective, controlled single-center study to determine the prevalence and types of ureteral stent symptoms in kidney transplant (KTx) recipients and compare them with nontransplant subjects. Materials and Methods: From December 2012 to June 2019, a total of 102 patients having undergone a KTx and Double-J stent (DJS) placement and 88 patients having undergone endourological lithotripsy and DJS placement were enrolled. The Ureteral Stent Symptom Questionnaire (USSQ) was administered to patients with a median of 25 (KTx) and 31 (urolithiasis) days after stent placement. USSQ scores were used to compare symptoms between the two groups. Results: Of the 190 patients enrolled, 88 belonged to the lithotripsy group (control group) and 102 to the KTx recipients' group. Mean score for urinary symptoms was 21.42 for KTx patients vs 27.53 for control patients with statistical significance (p < 0.001, CI -7.792 to -4.433). The visual analog scale, overall bother, pain at voiding, flank pain at voiding, and frequency of painkiller use scores were significantly higher for control patients than for KTx patients (p = 0.024, <0.001, <0.001, <0.001, and 0.014, respectively). Frequency of rest, changes in work duration, work domain score, suspicion of urinary tract infection (UTI), and need for professional assistance scores were significantly lower for KTx patients than the control. There were no significant differences in general health and sexual domains between groups. Conclusions: KTx recipients have significantly fewer urinary symptoms, pain, work-related disturbances, suspected UTIs, and hospitalizations associated with stent placement than urolithiasis patients.

Comparison of stent related symptoms in patients taking mirabegron, solifenacin, or tamsulosin: A double blinded randomized clinical trial

BACKGROUND

The present study aims to assess the efficacy of mirabegron, a novel beta-3 agonist for ameliorating stent related symptoms (SRSs) as compared to tamsulosin and solifenacin.

METHODS

Total of 150 patients undergoing ureteral stent placement following ureteroscopic lithotripsy, percutaneous nephrolithotomy, or laparoscopic/robotic pyeloplasty were randomized in 1:1:1 fashion to receive mirabegron 50 mg (group A), solifenacin 5 mg (group B), and tamsulosin 0.4 mg (group C) OD respectively. Patients were followed at POD10 (I visit), 4 weeks (II visit) after surgery, and 2 weeks post-stent removal. Validated vernacular version of ureteric stent symptoms questionnaire (USSQ) was administered to the patients at each visit.

RESULTS

Out of 150 patients randomized, 123 patients (A; n = 41, B; n = 40, and C; n = 42) completed the study. The groups were comparable in terms of urinary index score of USSQ at I and II visits (p = 0.119 and 0.076, respectively). A lower proportion of patients in group B experiencing bodily pain at II visit (p = 0.039), however, pain scores were comparable. Significantly lower general health index scores were observed in group A at I visit and over 4 weeks (p = 0.007). No significant differences were observed in other domains of USSQ. Age, sex, and surgical procedure undertaken did not significantly impact the scores in various USSQ domains.

CONCLUSION

Mirabegron demonstrates comparable benefit in alleviating SRSs with better general health indices and may be an effective alternative for SRSs, especially when tamsulosin or solifenacin are contra-indicated or poorly tolerated.

Prospective Evaluation of Antibiotic Management in Ureteral Stent and Nephrostomy Interventions

INTRODUCTION

Screening for and treating asymptomatic bacteriuria (ABU) or administering antibiotic prophylaxis is recommended during ureteral stent and nephrostomy interventions. This study investigates the frequency of postinterventional infectious complications to gain insight into the need for antibiotics.

METHODS

Between September 2016 and June 2019, 168 insertions/exchanges of ureteral stents or nephrostomies were recorded in a prospective multicenter study. Patients without a symptomatic UTI did not receive antibiotic treatment/prophylaxis. Asymptomatic patients in whom their urologist already administered an antibiotic treatment served as a comparative group. Follow-up included postinterventional complications within 30 days. Symptoms were assessed by the Acute Cystitis Symptom Score (ACSS) before and after the intervention. Predictors of increasing postinterventional symptoms were analyzed by a multivariable logistic regression model.

RESULTS

One hundred forty-five interventions were eligible. One hundred twenty-two (84.1%) interventions were performed without antibiotic treatment. Preinterventional ABU was detected in 54.4% and sterile urine in 22.8% (22.8% without culture). Postinterventional infectious complications did not differ between patients with versus without antibiotics. Transurethral interventions aggravate symptoms (p = 0.034) but do not increase infectious complications compared to percutaneous interventions. Patients without diabetes mellitus are at higher risk for increasing symptoms.

CONCLUSION

Results indicate that peri-interventional antibiotic treatment may be omitted in patients without symptomatic UTI. Symptoms must be differentiated between infectious and procedure-associated origins.

Impact of differential ureteral stent diameters on clinical outcomes after ureteroscopy intracorporeal lithotripsy: A systematic review and meta-analysis

In this meta-analysis we assessed whether the diameter of ureteral stents (4.7-5-Fr, 6-Fr) has an impact on the rate of occurrence of urinary tract symptoms and complications after successful URS and intracorporeal lithotripsy. A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A rigorous search for relevant studies published in MEDLINE, Embase, and the Cochrane Controlled Trials Register was conducted to find informative randomized controlled trials. The reference lists of relevant articles were also manually searched and reviewed. The protocol was prospectively registered at PROSPERO (CRD42020202164). All statistical evaluations were performed using RevMan software version 5.3.0. Seven articles comprising 547 patients were included in the meta-analysis. After placement of ureteral stents with different diameters for approximately 1 week, we found that ureteral stents with smaller diameters (4.7-5-Fr) were associated with significant improvements in the main domain scores on the Ureteral Stent Symptom Questionnaire, such as urinary symptoms (mean difference -4.47, 95% confidence interval -5.87 to -3.08; P < 0.00001) and body pain (mean difference -2.48, 95% confidence interval -4.37 to -0.59; P = 0.01), but poor outcomes in stent migration compared to ureteral stents with a 6-Fr diameter (odds ratio 3.00, 95% confidence interval 1.06-8.51; P = 0.04). However, there were no significant differences in Ureteral Stent Symptom Questionnaire scores with regard to work performance (mean difference -0.56, 95% confidence interval -2.52 to 1.40; P = 0.58), general health (mean difference -2.29, 95% confidence interval -4.95 to 0.37; P = 0.09), additional problems (mean difference -0.43, 95% confidence interval -1.02 to 0.15; P = 0.15), and complications such as fever (odds ratio 0.75, 95% confidence interval 0.24-2.39; P = 0.63). Ureteral stents with a diameter of 4.7-5-Fr have better outcomes than those with a diameter of 6-Fr, based on the Ureteral Stent Symptom Questionnaire pain and urinary tract symptoms scores. However, they are more prone to migration compared to those with a larger diameter.

Proximal Migration of Ureteral Stent With Ureteric Obstruction After Kidney Transplant

In this case report, we present the rare complication of proximal migration of ureteral stent after kidney transplant, and we describe our approach for its diagnosis and treatment. Although endoscopic management is the treatment of choice for retrieval of migrated stents, we reexplored the transplant in response to erroneous reporting of ureteral stent lying in an extravesicular position on a pelvic computed tomography scan. Subsequent exploration disproved the original interpretation of the image. Proximal stent migration may result from retrograde peristalsis and is generally related to suboptimal stent length.

Preoperative estimate of natural ureteral length based on computed tomography and/or plain radiography

To predict natural ureter lengths based on clinical images. We reviewed our image database of patients who underwent multiphasic computed tomography urography from January 2019 to April 2020. Natural ureteral length (UL_CTU) was measured using a three-dimensional curved multiplanar reformation technique. Patient parameters including age, height, and height of the lumbar spine, the index of ureteral length using kidney/ureter/bladder (KUB) radiographs (C-P and C-PS) and computed tomography (UL_CT) were collected. UL_CTU correlated most strongly with UL_CT. R square and adjusted R square values from multivariate regression were 0.686 and 0.678 (left side) and 0.516 and 0.503 (right side), respectively. UL_CTU could be estimated by the regression model in three different scenarios as follows:

UL_CT + C-P

UL_CTUL = 0.405 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 0.626 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_L – 0.508 cm

UL_CTUR = 0.558 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTR\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 0.218 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_R + 6.533 cm

UL_CT

UL_CTUL = 0.876 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTL\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 6.337 cm

UL_CTUR = 0.710 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× UL_CTR\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 9.625 cm

C-P

UL_CTUL = 0.678 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_L\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 4.836 cm

UL_CTUR = 0.495 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\times$$\end{document}× C-P_R\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+$$\end{document}+ 10.353 cm

We provide equations to predict UL_CTU based on CT, KUB or CT plus KUB for different clinical scenarios. The formula based on CT plus KUB provided the most accurate estimation, while the others had lower validation values but could still meet clinical needs.

Loop-tail stents fail in reducing stent-related symptoms: results of a prospective randomised controlled trial

OBJECTIVE

To compare stent-related symptoms (SRS) of loop-tail (LT) and conventional double J (DJ) stents after uncomplicated flexible ureterorenoscopy (fURS), in a prospective randomised controlled single-blind parallel-group study.

PATIENTS AND METHODS

Patients undergoing fURS were randomised into two groups: the LT Group received LT stents (Polaris™ Loop) and the DJ Group received conventional DJ stents (Vortek^® ). The stent was removed after 4 weeks. The Ureteric Stent Symptom Questionnaire (USSQ) was administered at 2 days, 4 and 8 weeks (baseline evaluation) after stent insertion. The primary endpoint was to compare the Urinary Symptom Index Score of the LT vs DJ groups at 4 weeks after stent insertion. The secondary endpoints were to compare the USSQ domains' subscores at 2 days and 4 weeks after stent insertion, USSQ single answers at 4 weeks, and the 4-week USSQ domains' subscores adjusted for baseline.

RESULTS

A total of 68 patients were randomised (34 LT and 34 DJ). The answers given at 4 weeks were not significantly different between the two groups for the Urinary Symptom Index Score (P = 0.982), Pain Index Score (P = 0.169), visual analogue scale (P = 0.276), and all the other domains of the USSQ. At 4 weeks, the single-answer analysis did not find any differences between the groups; the urinary symptoms were all comparable, as was the requirement for pain painkillers (P = 0.684) and pain during sex (P = 0.496). There were also no significant differences for every single domain score for the responses given at 2 days. The same applied to USSQ subscores at 4 weeks adjusted for the 8-week baseline results, which were also comparable.

CONCLUSIONS

The study found no differences in terms of SRS between the LT and DJ groups, either at 2 days or 4 weeks after stent insertion, with or without baseline correction.

Reduction of stent-associated morbidity by minimizing stent material: a prospective, randomized, single-blind superiority trial assessing a customized 'suture stent'

OBJECTIVES

To compare a customized 'suture stent' with a standard ureteric stent regarding stent-related symptoms, safety and efficacy.

MATERIALS AND METHODS

Patients with urolithiasis located proximal to the iliac vessel crossing, requiring stenting in preparation for secondary ureterorenoscopy (URS) were randomized to standard ureteric stenting or a suture stent. Secondary ureterorenoscopy was performed 2-6 weeks later. The Ureteral Stent Symptoms Questionnaire (USSQ) was completed after 1 week, on the day before URS and 2-6 weeks after stent removal. Stent efficacy and safety were systematically assessed.

RESULTS

A total of 88 patients were included in the analysis. The median (range) suture stent length was 10 (5-25) cm vs 26 cm for standard stents. Operation time was longer for insertion of the suture stent (24.0 vs 14.5 min; P < 0.001). Patients with a suture stent had a significantly lower USSQ urinary symptoms score 1 week after stent insertion, adjusted for baseline symptoms by subtracting scores from the final visit without indwelling stent (mean 7.1 vs 13.7, difference -6.6, 95% confidence interval [CI] -3.4 to -9.8; P < 0.001). Prior to secondary URS (after 2-6 weeks), baseline-adjusted urinary symptoms (mean 4.7 vs 12.2, difference -7.5, 95% CI -4.5 to -10.4; P < 0.001) and pain subscores (11.5 vs 17.6, difference -6.1, 95% CI -0.7 to -11.6; P = 0.004) were significantly lower in the suture stent group. All other USSQ subscores showed no significant differences. Adverse events occurred in 15 patients and were similarly frequent in the two groups. No significant differences were found between the groups regarding ureteric access during secondary URS.

CONCLUSION

Replacement of the distal part of ureteric stents by a suture can reduce stent-associated symptoms without restrictions regarding secondary stone removal or safety.

In Vivo Evaluation of a Novel Pigtail Suture Stent

OBJECTIVE

To compare pressure, dilation, and histology in a porcine model after stenting with a pigtail suture stent (PSS)-where the ureteral and bladder component consists of a suture and a double J (DJ) stent.

METHODS

Twelve pigs were studied with a PSS (4.8F/MiniJFil®) and DJ stent (4.8F/RocaJJ Soft) inserted in both sides, except in one where the DJ was not placed to serve as control. Intrapelvic pressure (IPP) and ureteral pressures were recorded. Five pigs were stented for 7 days, and the next 7 for 13-15 days, where a retrograde study was performed after stent removal. Ureteral histology in 4 and 3 pigs stented for 7- and 13-15 days, respectively, were assessed in a blinded manner.

RESULTS

In total, 11 renal units were stented with PSS and DJ, respectively. There was a rise in IPP and ureteral pressure after stenting. There were no significant differences in post-stenting pressures between DJ and PSS systems. Ureteral dilation occurred in 100% of DJ and 83% of PSS units. PSS suture migration occurred in 3 of 11. Gross edema at the ureteral orifice was greater with the DJ compared to the PSS (82% vs 18%; p = .003). Histology demonstrated greater inflammation at the ureteral orifice in the DJ group (2.3 vs 1; p = .016) when stented for 13-15 days.

CONCLUSION

There was no difference in IPP after stenting with a PSS compared to a DJ stent. When stented for 13-15 days, the PSS resulted in ureteral dilation, but with less edema and inflammation at the ureteral orifice.

Effect of Ureteral Stent Length and Position of Stent Coil in Bladder on Stent-Related Symptoms and Quality of Life of Patients

Introduction: Various standardized questionnaires can evaluate ureteral stent-related symptoms. The present study utilized a validated instrument, Ureteral Stent Symptoms Questionnaire (USSQ), to know the impact of the length of double J stent (DJS) in comparison to ureter length on patients and their quality of living.

Materials and Method: This study is a prospective clinical study conducted in the Department of Urology at a tertiary care center in South India. Patients who underwent DJS after endoscopic ureteral lithotripsy were included in the study. On a computerized tomography scan, the ureteral to stent length ratio (USR) was calculated. USSQ scores at the time of DJS removal and two weeks thereafter were recorded. The distal coil of the stent in the bladder was recorded as grade 1 - not crossing the midline and grade 2 - crossing the midline. Different symptom scores were compared between both grades of bladder coil and for USR of all the patients.

Result: A total of 157 patients were included in the study. Over 46 (29.3%) patients had grade-1 and 111 (70.7%) had grade-2 bladder coil. Totally 93 (59.23%) patients reported pain, while 64 (40.77%) patients had no pain. Grade-2 coil patients had more pain than grade 1 (P=0.01). There was a weak inverse relationship between the USR and urinary symptom (P=0.004), pain symptom (P=0.04), and quality of work (P=0.005).

Conclusion: Stent length or position of the intravesical stent coil does not appear to affect the quality of life except for the pain. Hence, choosing stent length according to ureteral length seems to have a minimal role in decreasing stent-related morbidity.

Korean ureter length: A computed tomography-based study

Purpose

We measured ureter length in healthy Koreans using reformatted computed tomography (UL_CT) and found ways to indirectly estimate ureter length by measuring LL_CT, the length between the ureteropelvic junction and the ureterovesical junction, and standing and sitting height.

Materials and Methods

A total of 508 ureters of 254 healthy patients (median age, 55.0 years; 148 males and 106 females) were included in this retrospective study. UL_CT, LL_CT, and sitting and standing body height were measured.

Results

The mean left and right UL_CT were 25.2±2.2 and 25.0±2.2 cm, respectively. The mean left and right LL_CT were 21.1±1.8 and 20.3±1.9 cm, respectively. Standing and sitting body height were 164.1±8.9 and 88.3±4.3 cm, respectively. Height was significantly correlated with UL_CT, but this relation was not linear (r²=0.064 standing height, 0.062 sitting height). However, LL_CT showed a significant linear correlation with UL_CT (r²=0.485). UL_CT can be estimated indirectly by the following equation: UL_CT=0.823×LL_CT+8.093.

Conclusions

We could measure the ureteral length of healthy Koreans by UL_CT. UL_CT could be estimated indirectly by LL_CT and standing and sitting height. Of these variables, LL_CT provided the most accurate estimate of ureteral length.

Clinical Effectiveness of Single Pigtail Suture Stent on Patient Comfort: A Double-Blind Prospective Randomized Trial

Background: A double-pigtail ureteral stent (DPUS) can cause untoward symptoms, such as urgency, frequency, urinary incontinence, hematuria, and body pain that are bothersome to patient's quality of life (QoL). By reducing the quantity of material in the bladder, it could be reasonable to decrease stent-related symptoms (SRSs). We aimed to evaluate the tolerability of single pigtail suture stent (SPSS) with a validated questionnaire after uncomplicated retrograde semirigid ureteroscopic lithotripsy (URSL). Materials and Methods: A total of 130 patients who underwent ureteral stent placement after URSL for unilateral symptomatic ureteral stones with <15 mm diameter were randomized prospectively into two groups. Polyurethane ureteral stent (6 Fr, 24 or 26 cm) was placed in all patients, which was removed postoperatively with a mean of 14 days. There were 65 patients in both groups. All subjects completed the ureteral stent symptoms questionnaire (USSQ), which explores the SRSs. The questionnaires were conducted on the day of stent removal (at week 2) with the stent in situ and 4 weeks after removal (at week 6, poststent). The severity of SRSs and QoL were compared between the two groups. Results: SPSS was associated with perfect effect on all domains of USSQ, except from sexual and general health index scores. Pain index scores, visual analog scores (VAS), and analgesic requirements in SPSS group were found significantly low compared with those in the DPUS group. The QoL scores were significantly better in patients indwelling SPSS. Conclusion: SPSS is a potentially beneficial option to minimize ureteral SRSs after uncomplicated URSL.

A New Customized Ureteral Stent with Nonrefluxing Silicone End-piece to Alleviate Stent-related Symptoms in Malignant Diseases

OBJECTIVE

To evaluate the stent-related symptoms using a new customized ureteral stent with a nonrefluxing silicone end-piece.

METHODS

By decreasing the amount of material within the bladder, it should be possible to attenuate the stent-related symptoms. To minimize the amount of material, 17 consecutive patients already fitted with a double-pigtail stent for malignant ureteral obstruction agreed to be fitted with a customized stent where the bladder loop was replaced by a nonrefluxing silicone end-piece. The ureteral stent symptom questionnaire was prospectively administered to patients at baseline with double-pigtail stent and Day 15 after customized stent placement.

RESULTS

No difficulty in the placement of the customized stent was encountered. No stent failure, no dislodgment and no calcification were observed 6 months after stenting. The scores for the main domain "Urinary symptoms" (34.4 ± 3.6 vs 23.0 ± 7.0; P = .0004) and the question "Global quality of life" (4.4 ± 2.0 vs 2.4 ± 2.1; P = .01) were significantly decreased by the replacement of the double-pigtail stent by the customized stent.

CONCLUSION

The customized ureteral stent may constitute an improvement in the field of stent-related symptoms and seems fit for use in its current shape. Studies exploring and exploiting new concepts are greatly required to reduce stent-related symptoms in all patients including those with cancer.

Challenges To Attenuate Ureteric Stent-Related Symptoms: Reflections On The Need To Fashion A New Dynamic Stent Design Consequent Upon A Case Report

Double-pigtail stent has been widely used in urology for half a century now, but this device reduces the patient’s quality of life. Moreover, indwelling stent-related symptoms induce additional suffering to the pre-existing bladder disease. Novel concepts to prevent stent-related symptoms are greatly required. It has been suggested that changes in the size, form and stent positioning could ease discomfort. By decreasing the amount of material within the bladder, it should be possible to attenuate the stent-related symptoms. A customized stent has been developed to alleviate bladder symptoms. The major characteristic of this stent was in the replacement of the bladder part of the double-pigtail stent by a nonrefluxing silicone end-piece. Three months after stenting, the patient complained of sudden discomfort in the bladder area. On the X-ray, the end-pieces of the customized stents seemed to have slipped in the bladder. The customized stents were replaced by new ones after truncating and adjusting their lengths to the exact ureteric length and stent-related symptoms were then improved again. In the field of stent-related symptoms, stent mobility needs more attention than its intravesical position. The case hereby reported illustrates the variations of the symptoms which seem related to the stent mobility, the necessary shaping of the stent and, the possible research avenues for an innovative dynamic ureteric stent.

Symptoms Associated With Long-term Double-J Ureteral Stenting and Influence of Biofilms

OBJECTIVE

To assess the symptoms associated with long-term Double-J ureteral stenting including the influence of biofilms on ureteral stents.

METHODS

Patients with long-term (>8 weeks) uni- or bilateral ureteral stents completed the Ureteral Stent Symptoms Questionnaire (USSQ) at the day of stent exchange. Repeated assessment of patients was possible to allow for analysis of intraindividual changes. Assessment of biofilm mass on the stents was performed according to a validated method, its correlation with the USSQ total score was defined as primary outcome. Secondary outcomes included further analyses of stent-associated symptoms and their temporal course.

RESULTS

A total of 87 stent indwelling periods in 35 patients were investigated. Median USSQ total score did not differ significantly between unilateral and bilateral stenting (42 vs 39 points; P = .17). An increasing total stent treatment time up to study inclusion did not correlate with the USSQ total score, but was significantly correlated with less urinary symptoms and a better quality of life. USSQ total score and subscores within individual patients did not significantly increase or decrease over the sequence of stent indwelling periods. Higher total biofilm masses were not associated with higher USSQ total scores or subscores.

CONCLUSION

Long-term Double-J stenting provides a valuable treatment option, if stent-associated symptoms are low during the initial indwelling period. Thus, symptoms remain stable over the long-term course and the majority of patients are satisfied with the treatment. Furthermore, biofilm formation on ureteral stents does not seem to be the relevant driver of symptoms.

Large Hepatic Subcapsular Hematoma Secondary to Double-J Stent Placement

Introduction and Background: Urinary diversion with the endoscopic Double-J stent is a frequent procedure; complications can include irritation, suprapubic or flank pain, vesicoureteral reflux, hematuria, or urinary infection. We report a case of hepatic subcapsular hematoma secondary to Double-J stent placement. Case Presentation: A 28-year-old woman presented with a history of Sjögren's disease, nephrocalcinosis, and chronic kidney disease (CKD). The patient underwent multiple percutaneous and endoscopic procedures during the previous 2 years: right kidney: extracorporeal shock wave lithotripsy (SWL) × 4, ureteroscopic lithotripsy × 2, percutaneous nephrolithotomy (PCNL), and retrograde intrarenal surgery; left kidney: SWL × 2, ureteroscopic lithotripsy × 5, and PCNL. Ultrasound imaging showed severe dilation in the right kidney and moderate dilation in the left kidney. CT scanning without contrast revealed a right pyelourethral dilation caused by a 13 mm ureteral lithiasis; also, cortical atrophy was observed. Urosepsis with exacerbated CKD was diagnosed and bilateral 7F Double-J stents were placed on both sides under general anesthesia. On postoperative day (POD) 8, the patient presented with pain in the right hemithorax and dullness to percussion. CT scans showed a heterogeneous hepatic subcapsular collection, of 15 × 7 × 23 cm, of hematic aspect, displacing vascular structures, and no active bleeding. Treatment was expectant and symptomatic. On POD 16, a new CT scan ruled out progression of the hematoma. The patient was finally discharged on POD 19. Four months later, bilateral semirigid ureteroscopy showed a right ureteral lithiasis of 8 × 7 mm, which was fragmented with a holmium laser. Nineteen months after the first episode, the patient is asymptomatic, with no residual lithiasis or hepatic hematoma. Conclusion: This case shows a very rare complication of Double-J stent placement that could be managed by conservative treatment.

Relation of postoperative pain medication to return for unplanned care after ureteroscopy

To determine whether the US Drug Enforcement Agency (DEA) class of narcotics prescribed to patients after ureteroscopy impacts their rate of return for unplanned care, a retrospective analysis of patients from February 2014 through March 2016 was performed. Data were collected for the first 90 days after surgery. Patients were divided into groups based on the narcotics schedule prescribed after surgery. Results showed that there was no statistical difference in return for unplanned care when comparing the groups based on their prescribed pain medication. Among the 475 patients, 17% returned to the emergency department after ureteroscopy, 12% contacted the clinic due to discomfort/pain, and 8% were readmitted to the hospital within 90 days of surgery. The data indicated that patients who were not prescribed a narcotic after surgery sought unplanned care at a slightly higher rate than those who were. In conclusion, the US DEA class of narcotics prescribed after ureteroscopy did not have a statistically significant impact on the rate of return for unplanned care. These findings may improve opioid stewardship in patients undergoing outpatient ureteroscopy.

Encrustations on ureteral stents from patients without urinary tract infection reveal distinct urotypes and a low bacterial load

BACKGROUND

Current knowledge of the urinary tract microbiome is limited to urine analysis and analysis of biofilms formed on Foley catheters. Bacterial biofilms on ureteral stents have rarely been investigated, and no cultivation-independent data are available on the microbiome of the encrustations on the stents.

RESULTS

The typical encrustations of organic and inorganic urine-derived material, including microbial biofilms formed during 3-6 weeks on ureteral stents in patients treated for kidney and ureteral stones, and without reported urinary tract infection at the time of stent insertion, were analysed. Next-generation sequencing of the 16S rRNA gene V3-V4 region revealed presence of different urotypes, distinct bacterial communities. Analysis of bacterial load was performed by combining quantification of 16S rRNA gene copy numbers by qPCR with microscopy and cultivation-dependent analysis methods, which revealed that ureteral stent biofilms mostly contain low numbers of bacteria. Fluorescence microscopy indicates the presence of extracellular DNA. Bacteria identified in biofilms by microscopy had mostly morphogenic similarities to gram-positive bacteria, in few cases to Lactobacillus and Corynebacterium, while sequencing showed many additional bacterial genera. Weddellite crystals were absent in biofilms of patients with Enterobacterales and Corynebacterium-dominated microbiomes.

CONCLUSIONS

This study provides novel insights into the bacterial burden in ureteral stent encrustations and the urinary tract microbiome. Short-term (3-6 weeks) ureteral stenting is associated with a low load of viable and visible bacteria in ureteral stent encrustations, which may be different from long-term stenting. Patients could be classified according to different urotypes, some of which were dominated by potentially pathogenic species. Facultative pathogens however appear to be a common feature in patients without clinically manifested urinary tract infection.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02845726 . Registered on 30 June 2016-retrospectively registered.

Freeze-casting porous chitosan ureteral stents for improved drainage

As a new strategy for improved urinary drainage, in parallel to the potential for additional functions such as drug release and self-removal, highly porous chitosan stents are manufactured by radial, bi-directional freeze-casting. Inserting the porous stent in to a silicone tube to emulate its placement in the ureter shows that it is shape conforming and remains safely positioned in place, also during flow tests, including those performed in a peristaltic pump. Cyclic compression tests on fully-hydrated porous stents reveal high stent resilience and close to full elastic recovery upon unloading. The drainage performance of the chitosan stent is evaluated, using effective viscosity in addition to volumetric flow and flux; the porous stent's performance is compared to that of the straight portion of a commercial 8 Fr double-J stent which possesses, in its otherwise solid tube wall, regularly spaced holes along its length. Both the porous and the 8 Fr stent show higher effective viscosities, when tested in the silicone tube. The performance of the porous stent improves considerably more (47.5%) than that of the 8 Fr stent (30.6%) upon removal from the tube, illustrating the effectiveness of the radially aligned porosity for drainage. We conclude that the newly-developed porous chitosan ureteral stent merits further in vitro and in vivo assessment of its promise as an alternative and complement to currently available medical devices. STATEMENT OF SIGNIFICANCE: No papers, to date, report on porous ureteral stents, which we propose as a new strategy for improved urinary drainage. The highly porous chitosan stents of our study are manufactured by radial, bi-directional freeze casting. Cyclic compression tests on fully-hydrated porous stents revealed high stent resilience and close to full recovery upon unloading. The drainage performance of the chitosan is evaluated, using effective viscosity in addition to volumetric flow and flux, and compared to that of the straight portion of a commercial 8 Fr double-J stent. The performance of the porous stent improves considerably more (47.5%) than that of the 8 Fr stent (30.6%) upon removal from the tube, illustrating the effectiveness of the radially aligned porosity for drainage. While further studies are required to explore other potential benefits of the porous stent design such as antimicrobial behavior, drug release, and biodegradability, we conclude that the newly-developed porous chitosan ureteral stent has considerable potential as a medical device.

Influence of biofilms on morbidity associated with short-term indwelling ureteral stents: a prospective observational study

PURPOSE

To evaluate the influence of biofilms on morbidity associated with short-term ureteral stenting using contemporary methods of biofilm examination and validated assessment of symptoms.

METHODS

Patients undergoing temporary ureteral stenting for secondary ureterorenoscopy due to urinary calculi were prospectively included. The German Ureteral Stent Symptoms Questionnaire (USSQ) was used to assess stent-associated morbidity. Biofilms were removed from stents using 'pinhole extraction', a novel, validated, abrasion-based technique. Extracted biofilms were analyzed for total mass, bacterial load and mineral components. Correlation between total biofilm mass and USSQ total score was the primary outcome variable analyzed using Spearman correlation. Secondary outcomes included correlations between various biofilm characteristics and symptoms.

RESULTS

94 patients were included in the analysis. Extracted biofilm mass had a median of 37.0 mg (0-310.2 mg) per stent. No correlation between total biofilm mass and USSQ total score was found (Spearman r = 0.012; p = 0.911). Correlations between biofilm characteristics and morbidity were generally weak and not significant. Significant correlations could be found between biofilm mass and hematuria (r = 0.280; p = 0.007), and between the number of bacteria (qPCR) and the USSQ subscore for pain (r = 0.243; p = 0.019) and the intake of analgesics (r = 0.259; p = 0.012).

CONCLUSION

Based on elaborated biofilm examination methods and validated self-reported outcome measures, our findings indicate that biofilms might aggravate some lower urinary tract symptoms but are not the main trigger for stent-associated morbidity in short-term ureteral stenting.

Ureteral stents in urolithiasis

Ever since the ureteral stent design was fitted with a curl on both sides to prevent it from migrating up or down the ureter some 40 years ago, its use has gained tremendous momentum, aiding in the rise and evolution of endourology and has confidently kept its place in modern time urology. Over the past four decades, several designs, coating and biomaterials have been developed, trying to reduce infection, encrustation and other stent related symptoms. As the ideal stent has not yet been discovered, different ways of helping patients with their complaints have been researched. This review will cover these aspects of stent use in urolithiasis.

Ureteral stent obstruction and stent's discomfort are not irreparable damages

Ureteral stent obstruction is a significant cause of morbidity and mortality from renal failure.

Alternative options for decompression include tandem ureteral stents but the amount of material in the bladder may severely impair the quality of life.

Following recurrent stent obstruction, a patient was fitted with tandem ureteral stent on both sides with a new nonrefluxing silicone end piece. After this procedure, renal function was improved with normal serum creatinine. The design of the new stent demonstrates the feasibility of the procedure. This new stent currently under prospective evaluation with tolerance questionnaire has demonstrated quite promising results in 10 patients.

Prediction of Bacteriuria Based on Clinical or Laboratory Parameters in Patients with Indwelling Ureteral Stents Before Ureterorenoscopy Should Not Substitute for Urine Cultures

OBJECTIVES

Urine cultures before secondary ureterorenoscopy (URS) are recommended to exclude bacteriuria, but results are often pending on the day of surgery. We sought to develop predictive models that reliably indicate the absence of bacteriuria in patients with indwelling ureteral stents based on readily available data.

PATIENTS AND METHODS

Records of patients undergoing secondary URS between 2014 and 2017 were assessed retrospectively. Patient characteristics, automated urinary sediment analysis, blood analyses, and results of urine cultures were analyzed using descriptive statistics, receiver operating characteristic curves, logistic regression, and model selection.

RESULTS

Of 462 patients, 101 (21.9%) had positive urine cultures. Urinary leucocytes, nitrite and pH, patient age and sex, and blood C-reactive protein (CRP) levels were associated with bacteriuria in logistic regression (p < 0.05), but did not sharply separate patients with and without bacteriuria. A multiple logistic regression model considering all six parameters and their interactions indicated a low probability of bacteriuria (8%) for 74% of the patients. Alternatively, recursive partitioning indicated low probability of bacteriuria (8%) if four criteria are simultaneously fulfilled (54% of the patients): Male, negative nitrite, urine leucocytes ≤1174/μL, and blood CRP ≤13 mg/L.

CONCLUSIONS

Bacteriuria in patients with indwelling ureteral stents before URS can hardly be predicted based on single clinical or laboratory parameters. Although the combination of relevant predictors allows for exclusion of urinary tract infection with relatively high confidence in most patients, the residual diagnostic uncertainty calls for optimized organizational measures to assure availability of urine cultures before surgery.

Evaluation of a New Design of Antireflux-biodegradable Ureteral Stent in Animal Model

OBJECTIVE

To determine the effects in urinary tract of a new antireflux-biodegradable ureteral stent.

MATERIALS AND METHODS

Thirty six ureters belonging to 24 pigs were used. The study began with endoscopic, nephrosonographic, and fluoroscopic assessments. Three study groups of ureters (n = 12) were then specified. In group I, a biodegradable antireflux ureteral stent (BDG-ARS) was inserted in the right ureter of 12 pigs. Group II comprised the left ureter of the same animals, in which a double-pigtail stent was placed for 6 weeks. Group III ureters, belonging to 12 additional animals, were subjected to a ureteropelvic junction obstruction model that was then treated by endopyelotomy and stenting with BDG-ARS. Follow-ups were performed at 3-6 weeks and at 5 months.

RESULTS

None of the ureters receiving the BDG-ARS showed any evidence of vesicoureteral reflux (VUR). BDG-ARS degradation took place in a controlled and predictable fashion from the third to the sixth weeks, and no obstructive fragments appeared. No differences were found between groups I and II regarding passive ureteral dilation, but significant differences were found regarding VUR and ureteral orifice damage. BDG-ARS always maintained distal ureteral peristalsis. BDG-ARS in group III showed a 50% positive urine culture rate and a 16.6% migration rate in both BDG-ARS groups.

CONCLUSION

BDG-ARS avoided VUR and bladder trigone irritation. In addition, this polymer combination and stent-braided design achieved a consistent biodegradation rate with no obstructive fragments and with uniform degradation between the third and the sixth weeks. Consequently, morbidity associated with ureteral stents might be reduced.