Urological Challenges during Pregnancy: Current Status and Future Perspective on Ureteric Stent Encrustation

The management of ureter hydronephrosis and urolithiasis during pregnancy has been changed by the adoption of ureteric stents. Despite their broad use for several other conditions, from emergency to elective settings, their complications cannot be ignored. Being most prevalent during pregnancy, urinary tract infections and stent encrustations are particularly common and can affect either fetal growth or maternal-fetal homeostasis, leading to obstetric complications. The main concern associated with ureteric stents is the indwelling time, which could represent the potential trigger of those complications. However, to ensure the optimal management of a ureteric stent during pregnancy, factors such as the grading of encrustations and the presence, size, and location of stones should be evaluated in pre-operative planning. As a consequence, a multimodal approach, including obstetrics, gynecologists, urologists, and nurses, is essential to ensure a complication-free procedure and successful ureteric stent removal. Finally, future research should focus on utilizing biodegradable and biocompatible materials to reduce and even eliminate the complications related to forgotten stents in order to reduce the financial burden associated with stent replacement and the management of stent-encrustation-related complications.

Development of the self-management scale for urolithiasis patients with indwelling double-J tube

PURPOSE

To develop a specific self-management scale applicable to patients with indwelling double-J tube in urolithiasis, and to test its reliability and validity.

METHODS

The construction and validation of our scale involved three stages. First, an initial version of the questionnaire was formed through literature analysis, group discussions, semi-structured interviews, and the Delphi method. Second, a pre-survey was conducted with 20 urolithiasis patients with indwelling double-J stent placement to test their understanding of the initial questionnaire items and its acceptability. Finally, a formal survey of 234 patients with indwelling double-J tube for urolithiasis was conducted, and the scale was tested for reliability and validity.

RESULTS

After the three stages, a specific self-management scale for urolithiasis patients with indwelling double-J tube was developed, consisting of 30 items across five dimensions with a cumulative contribution rate of 52.541%. The content validity index for item level ranged from 0.8 to 1, and the content validity index for the questionnaire level was 0.93. The correlation between each item and its dimension was > 0.4. The Cronbach's alpha coefficient for the overall questionnaire was 0.910, and the Cronbach's alpha coefficients for each dimension ranged from 0.672 to 0.865. The split-half reliability of the overall questionnaire was 0.864, and the split-half reliabilities for each dimension ranged from 0.659 to 0.827. The test-retest reliability of the overall questionnaire was 0.840, and the test-retest reliabilities for each dimension ranged from 0.674 to 0.818.

CONCLUSION

The specific self-management scale for urolithiasis patients with indwelling double-J tube has good reliability and validity, and it is a reliable and effective tool for evaluating and assessing the self-management level of patients with indwelling double-J tube in urolithiasis.

Does preoperative silodosin administration facilitate ureteral dilatation during flexible ureterorenoscopy? A randomized clinical trial

PURPOSE

To assess whether preoperative administration of silodosin can facilitate the placement of ureteral access sheath (UAS) prior to flexible ureteroscopy (F-URS) and reduce the occurrence of ureteric injury in challenging cases.

METHODS

This prospective randomized clinical trial was carried out on 147 patients diagnosed with upper ureteric stone or stone kidney, non-stented. The patients were randomly divided into two equal groups. Group A (silodosin group) included patients in whom F-URS was done with daily preoperative intake of 8 mg silodosin for 1 week and group B (placebo/control group) included patients in whom F-URS was done with daily preoperative intake of placebo tablets.

RESULTS

In group A, a total of 23 (33.3%) experienced ureteral wall injury following UAS insertion, while in group B, this occurred in 40 patients (59.7%). There was a statistically significant difference in the grade of ureteral wall injury between the two groups (P < 0.001). In the multiple regression analysis, age, operative time and silodosin were found to be significant risk factors for ureteral wall injury (P = 0.007, 0.041 and < 0.001, respectively).

CONCLUSIONS

The administration of silodosin prior to retrograde intrarenal surgery (RIRS) effectively prevented significant ureteral wall damage and reduced initial postoperative discomfort.

Is Stent on a String the New Gold Standard for Postureteroscopy Ureteral Drainage? Evidence from a Systematic Review

Introduction: Ureteral stents are widely used throughout urologic surgery, most commonly following ureteroscope (URS) procedures. This systematic review aims to assess the current evidence concerning stent on string (SOS) placed after URS and compare it with stents without strings (SWOSs). Methods: A systematic review was conducted on several databases using the preferred reporting items for systematic review and meta-analysis (PRISMA) methodology for studies in English language, for patients of all age groups, who had an SOS after URS for stone disease. Results: Of 1210 records identified, a total of 22 studies (20 adult and 2 pediatric studies) were included, with a total of 8382 patients. Of these, 3427 (40.9%) had SOSs inserted and 434 (11%) were in the pediatric age group. Our results show that SOS provides several advantages, and compared with SWOS, they were in situ for less time, with no difference in complications such as urinary tract infection or urinary symptoms. Furthermore, significant cost savings, less pain on removal, and high rates of safe home removal were reported in SOS, with >90% patients reporting that they would be happy to remove their SOSs at home. However, a small risk of stent dislodgment must be considered when making decisions regarding SOS placement after URS. Conclusion: SOS provides an excellent option after URS, especially in those patients with no intraoperative complication, and their placement is done as a routine insertion based on surgeon preference. These stents reduce dwell time, pain, cost, risks, and suffering involved from prolonged stenting, and majority of patients are happy to remove it themselves at home. Although their use seems to be still restricted in the current endourology practices, they are likely to become the new gold standard for routine URS in future, with more shared decision making and patient-reported outcome measures coming into the mainstream.

The Use of Prophylactic Ureteric Stents in Major Abdomino-Pelvic Sarcoma Surgery: Risks, Benefits, and Potential Complications

Here we present two cases of post-operative obstructive renal failure following major abdomino-pelvic sarcoma surgery. In both cases, prophylactic ureteric stents were inserted to aid the identification and protection of the ureters during resection of these complex retroperitoneal masses. In case one, obstructive renal failure occurred following ureteric stent removal on day 0 post-operatively. In case two, obstructive renal failure developed on day 1 post-operatively despite having a ureteric stent in situ. Here we propose that a combination of reflex anuria/ureteric edema and papillary sloughing led to the obstructive renal failure in both cases. Re-insertion of bilateral ureteric stents in case one, and replacement of a right ureteric stent in case two saw prompt excretion of urine and sloughy debris with rapid improvement of renal function. This article presents these cases in detail and further reviews the use of prophylactic ureteric stents in major abdomino-pelvic surgery along with the current guidelines for their usage.

Fluid mechanical performance of ureteral stents: The role of side hole and lumen size

Ureteral stents are indispensable devices in urological practice to maintain and reinstate the drainage of urine in the upper urinary tract. Most ureteral stents feature openings in the stent wall, referred to as side holes (SHs), which are designed to facilitate urine flux in and out of the stent lumen. However, systematic discussions on the role of SH and stent lumen size in regulating flux and shear stress levels are still lacking. In this study, we leveraged both experimental and numerical methods, using microscopic-Particle Image Velocimetry and Computational Fluid Dynamic models, respectively, to explore the influence of varying SH and lumen diameters. Our results showed that by reducing the SH diameter from 1.1 to 0.4 mm the median wall shear stress levels of the SHs near the ureteropelvic junction and ureterovesical junction increased by over 150 % , even though the flux magnitudes through these SH decreased by about 40 % . All other SHs were associated with low flux and low shear stress levels. Reducing the stent lumen diameter significantly impeded the luminal flow and the flux through SHs. By means of zero-dimensional models and scaling relations, we summarized previous findings on the subject and argued that the design of stent inlet/outlet is key in regulating the flow characteristics described above. Finally, we offered some clinically relevant input in terms of choosing the right stent for the right patient.

Economic burden of complicated ureteral stent removal in patients with kidney stone disease in the USA

Aim: To examine the medical costs of simple versus complicated ureteral stent removal. Materials & methods: We included adults with kidney stones undergoing simple or complicated cystoscopy-based stent removal (CBSR) post ureteroscopy from the 2014 to 2018 Merative™ MarketScan^® Commercial Database. The medical costs of patients with complicated and simple CBSR were compared. Results: Among 16,682 patients, 2.8% had complicated CBSR. Medical costs for patients with complicated CBSR were higher than for simple CBSR ($2182 [USD] vs $1162; p < 0.0001). Increased stenting time, increased age, southern US geography and encrusted stent diagnoses were significantly associated with complicated CBSR. Conclusion: Complicated ureteral stent removal doubled the medical costs associated with CBSR. Ureteral stents with anti-encrustation qualities may reduce the need for complicated CBSR and associated costs.

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.

Silodosin for Prevention of Ureteral Injuries Resulting from Insertion of a Ureteral Access Sheath: A Randomized Controlled Trial

BACKGROUND

The ureteral access sheath (UAS) is an ancillary device widely used by urologists, but acute ureter injury may occur following its insertion. Preoperative selective oral α1-blockers can reduce intraureteral pressure, and prevent ureteral wall injury during UAS insertion.

OBJECTIVE

To compare perioperative data of patients who underwent flexible ureterorenoscopy (fURS) with UAS with and without premedication with silodosin.

DESIGN, SETTING, AND PARTICIPANTS

Single-blind, 100 patients from a single institution who underwent retrograde intrarenal surgery for kidney and upper ureter stone removal were prospectively allocated from May 2018 to March 2019.

INTERVENTION

The experimental groups received silodosin for 3 d preoperatively.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint included ureteral injuries after UAS insertion that were assessed according to endoscopic classification. The secondary endpoint was an evaluation of whether premedication with silodosin had any effect on postoperative outcomes.

RESULTS AND LIMITATIONS

A total of 44 and 43 patients were randomly assigned to the control and experimental groups, respectively. Silodosin prevented significant postoperative ureteral injury involving the smooth muscle layer more successfully than in the control group (9.3% vs 27.3%; p = 0.031). There was no significant difference in the overall complication rate as determined by the modified Clavien-Dindo classification system and the computed tomography scan stone-free rate postoperatively. Patients who received silodosin before fURS reported lower pain scores than those in the control group using a visual analog scale (p = 0.009). Limitation included a lack of placebo comparison.

CONCLUSIONS

Our data suggest that preoperative silodosin protects against significant ureteral injury related to UAS insertion during fURS and decreases postoperative pain level. Silodosin premedication might be an effective and safe technique to replace prestenting.

PATIENT SUMMARY

We investigated the preventive effect of an α-blocker against perioperative complication caused by ureteral access sheath inserted during flexible ureterorenoscopy. Taking silodosin before surgery prevented ureter wall injury during surgery and immediately improved postoperative pain.

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.

Survey on ureTEric draiNage post uncomplicaTed ureteroscopy (STENT)

Objectives

To assess the feasibility of conducting a randomised controlled trial (RCT) to assess whether avoiding ureteric drainage is superior to performing ureteric drainage after Uncomplicated Ureteroscopy and/or Flexible Ureterorenoscopy (URS/FURS) treatment of a urinary tract stone in improving patient reported outcome measures (PROMs) and 30‐day unplanned readmission rates. A secondary objective was to understand current practice of urologists regarding ureteric drainage after uncomplicated URS/FURS (UU).

Material and methods

We undertook an online survey of urologists, circulated amongst members of international urological societies and through social media platforms. Uncomplicated URS/FURS was defined as completion of URS/FURS treatment for a urinary tract stone, with the absence of: ureteral trauma, residual fragments requiring further lithotripsy procedures, significant bleeding, perforation, prior urinary tract infection or pregnancy. The ureteric drainage options considered included an indwelling stent, stent on a string or a ureteric catheter. The primary outcome was to determine the proportion of urologists willing to take part in a RCT, randomising patients after UU to a “no ureteric drainage” arm or ureteric drainage arm. Secondary outcomes included determining in their current practice, the proportion of clinicians performing routine ureteric drainage after UU, the reasons for performing ureteric drainage following UU and their preferred optimal duration for ureteric drainage if it is used. The study was reported according to the Checklist for Reporting Results of Internet E‐Surveys (CHERRIES).

Results

Total of 468 respondents from 45 countries took part in the survey, of whom 303 completed the entire survey (65%). The majority agreed that they would be willing to randomise patients (244/303, 81%) in the proposed RCT. Perceived lack of equipoise to randomise was the most common reason for not being willing to participate (59/303, 19%).

92% (308/335) reported that they use ureteric drainage after UU. This was most often due to wanting to prevent possible complications from post‐operative ureteric oedema (77%) or to aid passage of small fragments (43%). Complexity of the case (i.e. impacted stone 90%) and length of the procedure (46%) were the most important intraoperative factors influencing the decision to use ureteric drainage post procedure. If required, the median stated ideal duration of ureteric drainage was 5 days (IQR: 3–7 days) after UU. If having UU personally, 30% would want no stent postoperatively and over half would prefer a stent on a string.

Conclusion

We have highlighted wide variation in practice regarding ureteric drainage after UU. Our results support the feasibility of an RCT evaluating if no ureteric drainage is superior to ureteric drainage in improving PROMs and 30‐day unplanned readmission rates following UU.

Biodegradable and Drug-Eluting Inorganic Composites Based on Mesoporous Zinc Oxide for Urinary Stent Applications

Conventional technologies for ureteral stent fabrication suffer from major inconveniences such as the development of encrustations and bacteria biofilm formation. These drawbacks typically lead to the failure of the device, significant patient discomfort and an additional surgery to remove and replace the stent in the worst cases. This work focuses on the preparation of a new nanocomposite material able to show drug elution properties, biodegradation and eventually potential antibacterial activity. Poly(2-hydroxyethyl methacrylate) or the crosslinked poly(2-hydroxyethyl methacrylate)-co-poly(acrylic acid) hydrogels were prepared by the radical polymerization method and combined with a biodegradable and antibacterial filling agent, i.e., flower-like Zinc Oxide (ZnO) micropowders obtained via the hydrothermal route. The physico-chemical analyses revealed the correct incorporation of ZnO within the hydrogel matrix and its highly mesoporous structure and surface area, ideal for drug incorporation. Two different anti-inflammatory drugs (Ibuprofen and Diclofenac) were loaded within each composite and the release profile was monitored up to two weeks in artificial urine (AU) and even at different pH values in AU to simulate pathological conditions. The addition of mesoporous ZnO micropowders to the hydrogel did not negatively affect the drug loading properties of the hydrogel and it was successfully allowed to mitigate undesirable burst-release effects. Furthermore, the sustained release of the drugs over time was observed at neutral pH, with kinetic constants (k) as low as 0.05 h⁻¹. By exploiting the pH-tunable swelling properties of the hydrogel, an even more sustained release was achieved in acidic and alkaline conditions especially at short release times, with a further reduction of burst effects (k ≈ 0.01–0.02 h⁻¹). The nanocomposite system herein proposed represents a new material formulation for preparing innovative drug eluting stents with intrinsic antibacterial properties.

Strategies to Improve Patient Outcomes and QOL: Current Complications of the Design and Placements of Ureteric Stents

Ureteric stents have played a vital role in relieving urinary obstruction in many urological conditions. Although they are extremely successful, stents have been associated with complications and reduced patients' health-related quality of life (HRQoL). There are many factors that may affect the quality and longevity of stents. In this review, we have highlighted the journey and innovation of ureteric stents through the modern day. A literature review was conducted to identify relevant articles over the last 20 years. There is a plethora of evidence with various indications for the use of ureteral stents and how they affect QoL. There is still ongoing research to develop the ideal stent with reduced encrustation, one that resists infection and is also comfortable for the patients. Stents made from metal alloys, polymers and biodegradable materials have unique properties in their own right but also have certain deficiencies. These have been discussed along with an overview of newly developed stents. Certain pharmacological adjuncts have also been highlighted that may be useful to improve patient's tolerance to stents. In summary, this paper describes the features of the different types of stents and the problems that are frequently encountered, including effect on patients' HRQoL and financial burden to healthcare providers.

A Microfluidic-Based Investigation of Bacterial Attachment in Ureteral Stents

Obstructions of the ureter lumen can originate from intrinsic or extrinsic factors, such as kidney stones, tumours, or strictures. These can affect the physiological flow of urine from the kidneys to the bladder, potentially causing infection, pain, and kidney failure. To overcome these complications, ureteral stents are often deployed clinically in order to temporarily re-establish urinary flow. Despite their clinical benefits, stents are prone to encrustation and biofilm formation that lead to reduced quality of life for patients; however, the mechanisms underlying the formation of crystalline biofilms in stents are not yet fully understood. In this study, we developed microfluidic-based devices replicating the urodynamic field within different configurations of an occluded and stented ureter. We employed computational fluid dynamic simulations to characterise the flow dynamic field within these models and investigated bacterial attachment (Pseudomonas fluorescens) by means of crystal violet staining and fluorescence microscopy. We identified the presence of hydrodynamic cavities in the vicinity of a ureteric occlusion, which were characterised by low levels of wall shear stress (WSS < 40 mPa), and observed that initiation of bacterial attachment occurred in these specific regions of the stented ureter. Notably, the bacterial coverage area was directly proportional to the number of cavities present in the model. Fluorescence microscopy confirmed that the number density of bacteria was greater within cavities (3 bacteria·mm^-2) when compared to side-holes of the stent (1 bacterium·mm^-2) or its luminal surface (0.12·bacteria mm^-2). These findings informed the design of a novel technological solution against bacterial attachment, which reduces the extent of cavity flow and increases wall shear stress over the stent's surface.

Cost analysis of removing pediatric ureteral stents with and without a retrieval string

BACKGROUND

Indwelling ureteral stents are commonly placed in urologic surgeries where optimal urinary drainage is necessary. In the pediatric population, removing a stent without retrieval string (SWOS) requires a secondary operation and additional anesthetic exposure. Although these burdens can be mitigated through the placement of a stent with retrieval string (SWS), fears of complications may prevent widespread adoption of this practice by pediatric urologists.

OBJECTIVE

The authors sought to assess the differential cost of removing SWS and SWOS. It was hypothesized that costs associated with removing SWS are significantly lower than those associated with removing SWOS, without increasing complications.

STUDY DESIGN

A retrospective chart review was performed on pediatric patients undergoing common urologic surgeries with concurrent stent placement at a single tertiary referral center. Charges and healthcare costs surrounding the removal of ureteral stents were evaluated using the institution-specific ratio of cost to charges, by estimating lost wages, and by exploring differences in poststent healthcare-related events that incur additional cost.

RESULTS

A total of 109 patients with a median age of 5 years (range: 6 months-20 years) were reviewed. A total of 29 patients had SWS, and 80 had SWOS. The theoretical cost of SWS removal in clinic was $400.48 compared with $2290.86 ± $119.30 for operative removal of SWOS, with mean difference of $1890.38 (P < 0.01). The mean stent duration of SWOS was 34.0 ± 13.2 days vs. 10.1 ± 4.9 days for SWS (P < 0.01). Subgroup analysis of the ureteral reconstruction group showed no difference in any complications (35% vs 27%, respectively), early dislodgment (7% vs 7%, respectively) or costly healthcare utilization (23% vs 20%, respectively) among patients with SWOS compared with those with SWS. In SWS group with early dislodgment, neither required a secondary procedure.

DISCUSSION

With rising healthcare expenditures, physicians must be able to provide cost-effective treatment while not compromising safety or outcomes. Unlike prior analyses of cost related to the type of the stent used, the present study specifically reviewed costs of removing SWS versus SWOS and evaluated rates of costly complications. The study findings provide a preliminary basis for advocating the more economical use of SWS when indicated. Lack of power and heterogeneity of the groups need to be addressed in future analyses with larger, matched cohorts.

CONCLUSION

Removal of SWS is more cost-effective than that of SWOS while maintaining similar safety outcomes and should be considered in certain pediatric urology cases to decrease healthcare cost. SWS should be preferred for uncomplicated ureteroscopy, but benefits are less certain in ureteral reconstruction; further studies are needed.

Improving Patient Education Materials: A Practical Algorithm from Development to Validation

Objectives

To generate an algorithm for systematic development and validation of written patient information in accordance with well-established and validated psychometric and statistical methods that can be applied to different fields of medicine.

Methods

A literature search was carried out in PubMed and Google Scholar. Methods were selected and combined to an algorithm. Feasibility and practicability is tested by the development of patient education materials on "ureteral stenting".

Results

The algorithm includes 4 study phases. After internal audit expert, readability of the first version is objectified using the Flesch Reading Ease formula. This draft is tested by a few patients performing semi-structured interviews using "The think aloud method" by Someren et al. Content validity is evaluated by a written survey by external consultants in accordance with Lawshe's "Quantitative approach to content validity". The final leaflet is developed at a consensus meeting and validated by patients based on the Consumer Information Rating Form. The new algorithm could be tested by the development of patient education materials on "ureteral stenting" as a test run.

Conclusion

We developed an algorithm for systematic development and validation of written patient information in accordance with well-established, validated psychometric and statistical methods. This algorithm can be applied to arbitrary fields of medicine.

Ureteric stents: Overview of current clinical applications and economic implications

Ureteric stents are one of the most crucial tools used for various clinical conditions in the urological field. Placement of a ureteric stent, for short- or long-term use, remains one of the commonest urological interventional procedures. In the past few decades, ureteral stents have undergone notable technological advancements. However, an ideal stent without significant side-effects is yet to be engineered. Indwelling ureteric stents are often accompanied by physical distress to the patient and clinical complications, such as bacterial adhesion, encrustation, malpositioning, stent fracture and forgotten stent syndrome, that influence patients' health-related quality of life. In the market, different stent types are available, designed to reduce infections, and improve patient symptoms and tolerance. In this review, we have emphasized the recent developments that have taken place in stent design, size, materials and coating. This overview looks at current practices and problems related to stents, along with clinical and economic considerations. Few trial studies have been enumerated in the context of utilization of a ureteral stent symptom questionnaire and various stent models to compare their effects in patients.

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.

Evaluating Efficacy of Antimicrobial and Antifouling Materials for Urinary Tract Medical Devices: Challenges and Recommendations

In Europe, the mean incidence of urinary tract infections in intensive care units is 1.1 per 1000 patient-days. Of these cases, catheter-associated urinary tract infections (CAUTI) account for 98%. In total, CAUTI in hospitals is estimated to give additional health-care costs of £1-2.5 billion in the United Kingdom alone. This is in sharp contrast to the low cost of urinary catheters and emphasizes the need for innovative products that reduce the incidence rate of CAUTI. Ureteral stents and other urinary-tract devices suffer similar problems. Antimicrobial strategies are being developed, however, the evaluation of their efficacy is very challenging. This review aims to provide considerations and recommendations covering all relevant aspects of antimicrobial material testing, including surface characterization, biocompatibility, cytotoxicity, in vitro and in vivo tests, microbial strain selection, and hydrodynamic conditions, all in the perspective of complying to the complex pathology of device-associated urinary tract infection. The recommendations should be on the basis of standard assays to be developed which would enable comparisons of results obtained in different research labs both in industry and in academia, as well as provide industry and academia with tools to assess the antimicrobial properties for urinary tract devices in a reliable way.

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.

Comparison of cost of care for tethered versus non-tethered ureteric stents in the management of uncomplicated upper urinary tract stones

BACKGROUND

Many surgeons use a stent after ureteroscopic lithotripsy (URSL). For short-term stenting purposes, a surgeon has the choice of either a tethered or a non-tethered stent. Stents may be associated with complications that entail an additional cost to their use. There is a paucity of data on the direct healthcare cost of using stent type after either primary or secondary URSL.

METHODS

We retrospectively reviewed medical records for patients who underwent URSL for uncomplicated urolithiasis between January 2013 and December 2013 at two tertiary referral hospitals. Costs data was sourced from the costing department with complete data available for 134 patients. The overall medical care cost was estimated by computing the cost of surgery, stent-related emergency department presentations, re-admissions and stent removal.

RESULTS

A total of 113 patients had tethered stents and 21 had non-tethered stents, with similar age and gender composition between the two groups and complications rates. The mean cost of URSL and stent placement was A$3071.7 ± A$906.8 versus A$3423.8 ± A$808.4 (P = 0.049), mean cost of managing complications was A$309.4 ± A$1744.8 versus A$31.3 ± A$98.9 (P = 0.096), mean cost of out-patient clinic stent removal was A$222.5 ± A$60 versus A$1013.6 ± A$75.4 (P < 0.001) for endoscopic stent removal, overall mean cost of care was A$3603.6 ± A$1896.7 versus A$4468.1 ± A$820.8 (P = 0.042) for tethered and non-tethered stents, respectively.

CONCLUSION

It is cheaper to use a tethered ureteric stent compared with non-tethered stents for short-term stenting after uncomplicated URSL, with a mean cost saving of A$864.5.

[Individualized evidence-based interventional stone treatment : One stone, many question marks?]

The treatment of urolithiasis is still one of the most frequent tasks in the daily urological practice. Driven by the technological developments, patient demands and also personal experiences of urologists, many interventional treatment options have been established. To identify the most suitable treatment option, it is of utmost importance to consider not only stone size and localization but also the individual situation of the patient and the published evidence, which despite all efforts often lags behind the technical and clinical reality.

The German linguistic validation of the Ureteral Stent Symptoms Questionnaire (USSQ)

PURPOSE

We developed and validated the German version of the Ureteral Stent Symptoms Questionnaire (USSQ) for male and female patients with indwelling ureteral stents.

METHODS

The German version of the USSQ was developed following a well-established multistep process. A total of 101 patients with indwelling ureteral stents completed the German USSQ as well as the validated questionnaires International Prostate Symptom Score (IPSS) or International Consultation on Incontinence Questionnaire (ICIQ) and the Short Form Health Survey (SF-36). Patients completed questionnaires at 1 and 2-4 weeks after stent insertion and 4 weeks after stent removal. Statistical analyses were performed to assess the psychometric properties of the questionnaire.

RESULTS

The German version of the USSQ showed good internal consistency (Cronbach's α = .72-.88) and test-retest reliability [intraclass correlation coefficient (ICC) = .81-.92]. Inter-domain associations within the USSQ showed substantial correlations between different USSQ domains, indicating a high conceptual relationship of the domains. Except from urinary symptoms and general quality of life, German USSQ showed good convergent validity with the corresponding validated questionnaires. All USSQ domains showed significant sensitivity to change (p ≤ .001).

CONCLUSION

The new German version of the USSQ proved to be a reliable and robust instrument for the evaluation of ureteral stent-associated morbidity for both male and female patients. It is expected to be a valid outcome measure in the future stent research.