Ureteral Stenting and Urinary Stone Management: A Systematic Review

Comparative study between the use of double J ureteric stents vs bander ureteric stents during robotic-assisted radical cystectomy with intra corporeal ileal conduit urinary diversion

Robotic-assisted radical cystectomy (RARC) is fast becoming the standard of care with comparable oncological outcomes to open surgery for patients with muscle-invasive bladder cancer. Ileal conduit is by far the most popular means of urinary diversion following a cystectomy. Use of stents is common practice to reduce uretero-enteric anastomosis-related complications. In the current study, practice was changed from the use of Double J (DJ) stents to bander stent intraoperatively. The potential advantages of using bander stent are avoiding second surgery for stent removal and easier change under local anaesthetic in the interventional radiology department. To compare the incidence of blocked, slipped stents and rate of ureteroileal anastomotic stricture after RARC with intracorporeal ileal conduit between practices of using DJ stents and bander stents. Retrospective analysis of all the patients undergoing Robotic radical cystectomy and intracorporeal ileal conduit between June 2014 and August 2023 was done. Initially, all intracorporeal anastomosis were covered with DJ stents. The practice was changed to cover the anastomosis with bander stent in November 2020. Number of patients needing re-surgery for blocked, slipped stents and ureteroileal anastomotic stricture were analyzed and compared using Chi-square analysis and Fisher's exact test (P < 0.05). A total of 168 patients underwent RARC with intracorporeal ileal conduit between June 2014 and August 2023 of which 128 patents were diverted with DJ stents and 40 with bander stent. The mean age and the patient demographics between the two groups were comparable. Of the 128 patients who were diverted with DJ stents, 6 (4.7%) had blocked stents, 3 (2.3%) had slipped stents, and 3 (2.3%) developed ureteroileal stricture needing readmission and urgent invasive intervention to exchange the stent or nephrostomy tube, whereas only 1 (2.5%) of the 40 patients with bander stent had blocked stent which was changed under local anaesthetic in the interventional radiology suite with no slipped stents reported and 2 (5%) had ureteroileal stricture who needed nephrostomies. Intraoperative ureteric stenting using bander stent has the potential to reduce the incidence of stent-related complications, such as blockage, slippage, and ureteroileal anastomotic stricture, following RARC with intracorporeal ileal conduit urinary diversion. Additionally, managing bander stent-related complications is less invasive with lower rate of readmission postoperatively compared to managing DJ stent-related ones.

The Saudi urological association guidelines on urolithiasis

Aims

The Saudi Urolithiasis Guidelines are a set of recommendations for diagnosing, evaluating, and treating urolithiasis in the Saudi population. These guidelines are based on the latest evidence and expert consensus to improve patient outcomes and optimize care delivery. They cover the various aspects of urolithiasis, including risk factors, diagnosis, medical and surgical treatments, and prevention strategies. By following these guidelines, health-care professionals can improve care quality for individuals with urolithiasis in Saudi Arabia.

Panel

The Saudi Urolithiasis Guidelines Panel consists of urologists specialized in endourology with expertise in urolithiasis and consultation with a guideline methodologist. All panelists involved in this document have submitted statements disclosing any potential conflicts of interest.

Methods

The Saudi Guidelines on Urolithiasis were developed by relying primarily on established international guidelines to adopt or adapt the most appropriate guidance for the Saudi context. When necessary, the panel modified the phrasing of recommendations from different sources to ensure consistency within the document. To address areas less well covered in existing guidelines, the panel conducted a directed literature search for high quality evidence published in English, including meta analyses, randomized controlled trials, and prospective nonrandomized comparative studies. The panel also searched for locally relevant studies containing information unique to the Saudi Arabian population. The recommendations are formulated with a direction and strength of recommendation based on GRADE terminology and interpretation while relying on existing summaries of evidence from the existing guidelines.

Comparison of immediate versus post-stenting ureteroscopy for ureteral stones treatment

Ureteroscopy is a highly effective treatment for ureteral stones, characterized by a high stone-free rate and a low need for re-treatment. Ureteral stent placement can improve the insertion of the ureteral access sheath and ureteroscope but may be associated with higher morbidity prior to and after ureteroscopy. The study aimed to compare immediate versus post-stenting ureteroscopy for ureteral stone treatment in terms of operative time, intra- and post-operative complications, length of hospital stay, and stone-free rate. This prospective study involved 126 patients with ureteral stones divided into two groups: the post-stenting ureteroscopy group (PS-URS), who underwent primary ureteral stenting by double J followed by delayed ureteroscopy, and the immediate ureteroscopy group (I-URS), who underwent immediate ureteroscopy without previous stenting. Sixty-six patients were included in the PS-URS group and 60 patients in the I-URS group. Results were comparable, with no significant differences between both groups. The mean operative time was 33.77±3.51 minutes for the PS-URS group and 34.60±2.01 minutes for the I-URS group. The average length of hospital stay was 0.84±2.55 days for PS-URS and 0.92±1.96 days for I-URS patients. The stone-free rate was 97% in the PS-URS group and 95% in the I-URS group. The overall complication rate was 4.5% versus 5% in the PS-URS and I-URS groups, respectively, with all complications being minor and managed effectively. Immediate ureteroscopy is a safe and relevant operative approach for ureteral stones, with comparative results for post-stenting delayed ureteroscopy.

2022 Recommendations of the AFU Lithiasis Committee: Ureteroscopy and ureterorenoscopy

Technical advances, including miniaturization, have improved the deflection and optical performance of the ureteroscopes, and the availability of dedicated disposable devices have led to their increasing use for kidney and ureteral stone management. Ureterorenoscopy brings diagnostic evidence through the endoscopic description of stones and renal papillary abnormalities. Currently, intracorporeal lithotripsy during ureterorenoscopy is based on laser sources. Routine ureteral stenting is not necessary before ureterorenoscopy, especially because preoperative stenting for>30 days is considered as an independent risk factor of infection. Ureteral access sheaths allow the easy and repeated access to the upper urinary tract and thus facilitate ureterorenoscopy. Their use improves vision, decreases intrarenal pressure, and possibly reduces the operative time, but they may cause ureteral injury. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendation (CPR) method and the ADAPTE method, depending on whether or not the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU 2022]) and their adaptability to the French context.

Predicting urine culture results in candidates for lithotripsy

Background

Urological guidelines assert that "urine culture should be obtained" before surgical management of ureteral or kidney stones. Thus, many surgeries are delayed by 1-3 days until the results of urine culture are available. During this time, the patient frequently experience pain and possible kidney damage. We investigated the hypothesis that it is possible to predict the results of urine culture in candidates for surgical intervention using parameters that are accessible immediately upon admission.

Materials and methods

A database of 1000 patients who underwent either percutaneous nephrolithotomy (PCNL) or ureteroscopy/retrograde intrarenal surgery was analyzed. Eleven parameters potentially related to urinary infections and accessible to the clinician at the emergency department were correlated with the preoperative urine culture results.

Results

Of the patients, 234 (23.4 %) had positive cultures. On multivariate analysis, only sex, hydronephrosis grade, and history of previous nephrolithotomy were significantly associated with a positive preoperative urine culture. The risk of a positive culture can be easily determined from a simple table or an Excel-based calculator. This risk could be as low as 0.45% for a man without a history of PCNL and no hydronephrosis (4% in a woman with similar parameters) or as high as 79.5% in a man with a history of PCNL and hydronephrosis (85% in a woman with similar parameters).

Conclusions

The risk of preoperative positive urine culture can be predicted using 3 parameters that are accessible upon admission. In low-risk cases, prompt surgical treatment can be provided, eliminating the anticipation time for urine culture results.

Comparison of the Removal Efficiency and Safety of Magnetic Versus Conventional Ureteral Stents: A Systematic Review and Meta-analysis

Context

The incidence of urolithiasis is increasing year by year. Ureteral stents are a popular treatment option for this condition. Efforts to improve the material and structure of stents to increase comfort and reduce complications have led to the introduction of magnetic stents.

Objective

To evaluate differences in removal efficiency and safety for magnetic and conventional stents.

Evidence acquisition

This study was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Data were extracted according to the PRISMA principles. We collected and combined data from randomized controlled trials on magnetic versus conventional stents to evaluate the efficiency of their removal and the associated effects. Data synthesis was performed using RevMan 5.4.1 and heterogeneity was evaluated using I² tests. A sensitivity analysis was also performed. Key metrics included the stent removal time, Visual Analog Scale (VAS) pain scores, and Ureteral Stent Symptom Questionnaire (USSQ) scores for various domains.

Evidence synthesis

Seven studies were included in the review. We found that magnetic stents had a shorter removal time (mean difference [MD] -8.28 min, 95% confidence interval [CI] -15.6 to -0.95; p = 0.03) and their removal was associated with less pain (MD -3.01 points, 95% CI -3.83 to -2.19; p < 0.01) in comparison to conventional stents. USSQ scores for urinary symptoms and sexual matters were higher for magnetic than for conventional stents. There were no other differences between the stent types.

Conclusions

Magnetic ureteral stents have the advantages of a shorter removal time, less pain during removal, and low cost in comparison to conventional stents.

Patient summary

For patients undergoing treatment of urinary stones, a thin tube called a stent is often temporarily inserted in the tube between the kidney and the bladder to allow stones to pass. Magnetic stents can be removed without any need for a second surgical procedure. Our review of studies comparing two types of stents suggests that magnetic stents are superior to conventional stents in terms of efficiency and comfort during removal.

Stents in Veterinary Medicine

Stenting in veterinary medicine has been a rapidly growing method of interventional surgery for several years. This procedure is usually performed in the respiratory and urinary tracts, but there are cases of stenting of blood vessels or gastrointestinal structures. It is based on maintaining the permeability of a given tubular structure, thus allowing the passage of gas or liquid. This procedure is often performed as a first-line treatment in situations where pharmacological agents do not work and as an alternative method, often cheaper than the classically performed ones. There are also cases where stenting is used as a palliative treatment, e.g., to enable defecation in colonic obstruction due to tumour infiltration of the colon wall. Stenting is often a life-saving or comfort-improving procedure for animals, but one should also be aware of possible postoperative complications and be prepared for any adversity. For this reason, this review provides an insight into the current knowledge in veterinary medicine about stenting and the consequences associated with this procedure.

Preventive effect of surface charge on encrustation of biodegradable ureteral stents

Prevention of encrustation on the surface has always been the biggest challenge for urological implants. In the field of ureteral stent design, biodegradability has attracted much attention in recent years, because biodegradable ureteral stents not only avoid secondary intervention, but also prevent encrustation due to surface renewal by degradation process. Furthermore, researches have focus on some surface parameters to provide guidance for the development of stent materials, such as hydrophilicity or surface charge. In this work, we synthesized two types of poly(ester-carbonate)s, poly(L-lactide-co-5-amino-1,3-dioxan-2-one) (P(LA-co-AC)) containing amino, and poly (L-lactide-co-5-methyl-5-carboxyl-1,3-dioxan-2-one) (P(LA-co-MCC)) containing carboxyl. Blending P(LA-co-AC) and P(LA-co-MCC) with poly(L-lactide-co-Ɛ-caprolactone) (PLACL) respectively, two types of ureteral stent materials were prepared. Due to the influence of ions formed by the dissociation of amino and carboxyl, two types of materials show differences in surface charge analyses. We further developed a dynamic urinary extracorporeal circulation (DUEC) system to assess in vitro encrustation of materials with different surface charges. The results of this comparative study identified that the materials with strong negative surface charge were most favorable for use as ureteral stent, and provided a new approach to surmount the problems faced by urological surgery which complied with the future trend of biodegradable ureteral stent design.

Bacterial Colonization Incidence before and after Indwelling Double-J Ureteral Stents

The upper urinary tract stenting allows to restore the ureteral patency in various situations. However, one of the main disadvantages of stenting is bacterial contamination, which can be a source of persistent infections that hardly respond to antibiotic therapy. The aim of this study was to investigate the local spectrum of bacterial pathogens and their susceptibility to antibiotics in order to optimize antibacterial therapy after upper urinary tract stenting. A prospective observational study was conducted in which 140 urine samples were examined (70 before stenting and 70 after stenting). Bacterial growth was detected in 37 patients (52.8%) before stenting and in 43 patients (61.4%) after stenting. E. coli (13 (28.8%)) and Streptococcus spp. (8 (17.6%)) strains were more commonly detected before stenting; P. aeruginosa (15 (31.2%)) and E. coli (8 (16.6%)) were usually revealed after stenting. The proportion of P. aeruginosa strains after stenting grew from 4.4% up to 31.2%. E. coli strains were resistant to ampicillin (92.3% before and 100% after stenting). Three strains of E. coli (23.1%) and six strains of P. aeruginosa (40%) were multidrug-resistant. Determination of the bacterial sensitivity to antibiotics and identification of antibiotic-resistant forms of bacteria is a factor in reducing the risk of complications and optimizing antibiotic therapy during the upper urinary tract stenting.

Silicone vs. Polyurethane Stent: The Final Countdown

Ureteric stents are conventionally used in daily urological practice. There is ongoing debate on the superiority of different stent materials, particularly in terms of patient tolerance. We conducted a literature review to compare silicone stents and stents made of other materials from a patient tolerability perspective. We conclude that silicone stents are better tolerated but further research is required.

A systematic review of magnetic versus conventional ureteric stents for short term ureteric stenting

Ureteric stents play an essential role in urology. However, patients can suffer a range of stent-related symptoms with stent in situ and during removal. Conventional ureteric stents are removed using a flexible cystoscopy, whereas magnetic stents may be rapidly removed with a smaller catheter-like retrieval device. The primary aim of this systematic review was to compare the morbidity including pain associated with conventional versus magnetic ureteric stents. The secondary aim was cost comparison. Searches were performed across databases, including Medline, Scopus, Embase and Cochrane. This review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The search from the 5 databases returned a total of 358 articles. After duplicates were removed as well as the inclusion and exclusion criteria applied, a total of 6 studies were included in the final review. Ureteric Stent Symptoms Questionnaire (USSQ) and Visual Analogue Score (VAS) were used in most of the studies. All the studies reported that magnetic ureteric stents resulted in a reduction in the pain on the removal of magnetic ureteric stents, and no statistically significant difference with indwelling ureteric stents. Furthermore, majority of the studies reported a reduction in the cost associated with magnetic ureteric stents. There is no significant difference in pain from indwelling ureteric stents. There is a reduction in pain with the removal of magnetic ureteric stents compared to conventional removal via cystoscopy and an associated reduction in cost.

Early diagnosis and management of maternal ureterohydronephrosis during pregnancy

Maternal ureterohydronephrosis (UHN) is a common anatomical change during the evolution of pregnancy, diagnosed especially after the 20th week of pregnancy. The aim of the present study was to evaluate the stages of UHN during pregnancy, depending on the gestational age, and to monitor the symptomatology and the adequate management. A total of 58 pregnant women with UHN, hospitalized in the Constanta County Emergency Hospital, were included in the present study, and had nephrological monitoring using ultrasound examination. Right UHN was observed in all cases and left UHN was observed in only 67.24% of the cases. Regarding the gestational age, right UHN grade III was most commonly seen between 27 and 31 weeks of pregnancy (48.6% of total right UHN grade III from the studied group). The data showed that gestational age and grade of UHN had a highly dependent association in the studied group. The majority of our patients (67.24%) were symptomatic, and the most common complaint on presentation was lumbar pain. According to the visual analog scale (VAS) of the lumbar pain, the group could be distributed as follows: 17.24% with severe pain, 36.21% with moderate pain and 13.79% with mild pain. Eight pregnant women (13.79%) from the present study developed UHN due to passage of a ureteral stone, although the majority of the patients experienced complications with urinary tract infection and acute kidney injury. In addition, 97% of the symptomatic UHN responded to conservatory treatment and only 2 patients (3.45%) with severe symptomatic UHN needed ureteral stent insertion. Data analysis was performed using IBM SPSS Statistics 23. The study highlighted the existence of an association between gestational age and UHN grading.

Fluid mechanical modeling of the upper urinary tract

The upper urinary tract (UUT) consists of kidneys and ureters, and is an integral part of the human urogenital system. Yet malfunctioning and complications of the UUT can happen at all stages of life, attributed to reasons such as congenital anomalies, urinary tract infections, urolithiasis and urothelial cancers, all of which require urological interventions and significantly compromise patients' quality of life. Therefore, many models have been developed to address the relevant scientific and clinical challenges of the UUT. Of all approaches, fluid mechanical modeling serves a pivotal role and various methods have been employed to develop physiologically meaningful models. In this article, we provide an overview on the historical evolution of fluid mechanical models of UUT that utilize theoretical, computational, and experimental approaches. Descriptions of the physiological functionality of each component are also given and the mechanical characterizations associated with the UUT are provided. As such, it is our aim to offer a brief summary of the current knowledge of the subject, and provide a comprehensive introduction for engineers, scientists, and clinicians who are interested in the field of fluid mechanical modeling of UUT. This article is categorized under: Cancer > Biomedical Engineering Infectious Diseases > Biomedical Engineering Reproductive System Diseases > Biomedical Engineering.

A randomized trial investigating clinical outcomes and stent-related symptoms after placement of a complete intra-ureteric stent on a string versus conventional stent placement

OBJECTIVE

To compare stent-related symptoms (SRS) associated with conventional ureteric JJ stent (CUS) placement and SRS associated with placement of a modified complete intra-ureteric stent (CIUS) with extraction suture, designed to minimize SRS, using the validated Ureteral Stent Symptom Questionnaire (USSQ).

MATERIALS AND METHODS

We randomized 124 patients who had undergone uncomplicated ureteroscopic lithotripsy into a CIUS and a CUS placement group. USSQ scores were evaluated on postoperative days 1 and 7 (just before stent removal) and 4 weeks after stent removal (control values). Pain scores on a visual analogue scale (VAS) after stent removal were also recorded. Subdomain analysis of all SRS and stent-related complications were also compared.

RESULTS

No significant intergroup differences were found in the domain scores for urinary symptoms (P = 0.74), pain (P = 0.32), general health (P = 0.27), work (P = 0.24), or additional problems (P = 0.29). However, a statistically significant difference was noted in VAS scores (P = 0.015). Analysis of subdomains of USSQ item scores showed the CIUS group had significantly better scores for urge incontinence (1.21 vs 1.00; P ≤ 0.001), discomfort on voiding (2.07 vs 1.50; P ≤ 0.001), difficulties with respect to light physical activity (1.131 vs 1.00; P ≤ 0.001), fatigue (1.84 vs 1.57; P = 0.002), feeling comfortable (3.68 vs 3.16; P = 0.003), need for extra help (1.96 vs 1.00; P ≤ 0.001), and change in duration of work (4.27 vs 1.86; P ≤ 0.001). However, the patients in the CIUS group were sexually inactive for the time during which the stent was indwelling (mean: 7.34 days). There was no difference in complication rates between the two groups.

CONCLUSION

The use of a CIUS with strings after Ureteroscopy decreases SRS.

Is Retrograde Intrarenal Surgery as Safe for Children as It Is for Adults?

INTRODUCTION

The primary aim of this study is to compare the efficacy and safety of retrograde intrarenal surgery (RIRS) among the children and adults with similar stone burdens and locations. Also, the secondary aim of this study is to identify the factors affecting the stone-free rates (SFRs) of RIRS.

METHODS

We retrospectively compared perioperative results, SFRs, and complication rates (CRs) between pediatric (group 1, n: 55) and adult (group 2, n: 220) age groups diagnosed with kidney stones and treated by flexible ureterorenoscopy using the same instruments. Furthermore, multivariate analysis was performed to determine the factors affecting the SFR.

RESULTS

A total of 275 patients (pediatric group: 55; adult group: 220) were included in this study. The mean age of pediatric and adult groups was 7.2 ± 5.3 and 43.9 ± 15.1, respectively. The mean stone size was 13.9 ± 6.6 mm in the pediatric group compared to 14.8 ± 6.7 mm in the adult group (p = 0.35). Stone localizations and number were similar. JJ stenting for passive dilatation and use of UAS were higher in the pediatric group (p = 0.002; p = 0.017). However, postoperative double pigtail stenting rate was higher in the adult group (p < 0.001). Total CR was 13.8% and mostly Clavien I-II, and no difference was observed between the 2 groups (p = 0.541). The SFRs between the groups were similar (pediatric group: 81.8%; adult group: 78.2%; p = 0.554). On multivariate analysis, stone size (p < 0.001) and lower calyx stone (p < 0.001) were the negative predictive factors for SFR.

CONCLUSION

There are small technical differences between pediatric patients and adult patients in our study, but RIRS in children is as safe and efficient as it is in adults.

A randomized prospective study: assessment of transient ureteral stenting by mono-J insertion after primary URS and stone extraction (FaST 3)

To compare the outcome of a short-term insertion of a mono-J catheter for 6 h following ureteroscopic stone removal to a conventional double-J catheter. This single-center academic study (Fast Track Stent study 3) evaluated stenting in 108 patients with urinary calculi after ureterorenoscopy. Patients were prospectively randomized into two study arms before primary ureterorenoscopy: (1) mono-J insertion for 6 h after ureterorenoscopy and (2) double-J insertion for 3-5 days after ureterorenoscopy. Study endpoints were stent-related symptoms assessed by an ureteral stent symptom questionnaire (USSQ) and reintervention rates. Stone sizes and location, age, operation duration, BMI, and gender were recorded. Of 67 patients undergoing ureterorenoscopy, 36 patients were analyzed in the double-J arm and 31 patients in the mono-J arm. Mean operation time was 27.5 ± 1.3 min versus 24.0 ± 1.3 min, and stone size was 5.2 mm versus 4.5 mm for mono-J versus double-J, respectively (p = 0.06 and p = 0.15). FaST 3 was terminated early due to a high reintervention rate of 35.5% for the mono-J group and 16.7% for the double-J group (p = 0.27). One day after ureterorenoscopy, USSQ scores were similar between the study arms (Urinary Index: p = 0.09; Pain Index: p = 0.67). However, after 3-5 weeks, the Pain Index was significantly lower in those patients who had a double-J inserted after ureterorenoscopy (p = 0.04). Short-term insertion of mono-J post-ureterorenoscopy results in similar micturition symptoms and pain one day after ureterorenoscopy compared to double-J insertion. The reintervention rate was non-significant between the treatment groups most likely due to the early termination of the study (p = 0.27). Ethics approval/Trail Registration: No. 18-6435, 2018.

To what extent have key recommendations from the Getting It Right First Time programme for urology in England been implemented?

Objectives:

The Getting It Right First Time programme was set up to reduce unwarranted variation in healthcare practice and outcomes in England. The aim of this study was to investigate early changes in practice in urology based on the recommendations made.

Subjects and methods:

Data were extracted from the Hospital Episodes Statistics database from January 2014 to December 2019. The dates of visits by members of the Getting It Right First Time team were taken as the intervention point. Interrupted time series analysis was used to identify trends pre and post intervention.

Results:

Following the Getting It Right First Time visits, there was evidence of a significant increase in the proportion of patients seen as day cases for transurethral resection of bladder tumour and decreased use of stents and increased use of ureteroscopy or extracorporeal shock wave lithotripsy on first presentation with ureteric stones. However, there was no significant change in waiting times for surgery to treat patients who had an emergency presentation with urinary retention.

Conclusions:

There is evidence that the recommendations made are already having an impact on clinical practice. The reasons why some recommendations appear to be harder to implement requires further investigation.

Level of evidence:

2b

Striking a balance: outcomes of short-term Mono-J placement following ureterorenoscopy

To evaluate factors affecting the outcomes of short-term Mono-J insertion for 6 h following ureteroscopic stone removal. Patients treated with a Mono-J for 6 h after ureterorenoscopy and stone removal were analysed. FaST 1 and 2 (Fast Track Stent Studies), two consecutive single academic centre studies, were conducted between August 2014 and April 2018. In each study, we randomized patients with renal or ureteral calculi to two groups before ureterorenoscopy. FaST 1 compared a Mono-J insertion for 6 h versus Double-J insertion for 3–5 days after ureterorenoscopy. FaST 2 compared a Mono-J insertion to a tubeless procedure in the same clinical setting. All patients were pre-stented for 3–5 days before URS. The study endpoint was stent-related symptoms as assessed by a validated questionnaire (USSQ). Results were stratified by clinical parameters, stone characteristics and operation details. 108 of 156 initially randomized patients undergoing ureterorenoscopy were included. USSQ scores covering the time 3–5 weeks after stone removal showed a significantly reduced urinary symptoms and pain index compared to the scores before ureterorenoscopy. USSQ results before and after stone removal did not correlate with stone size or operation time and did not differ significantly depending on stone localization, the treating endourologist, or ureterorenoscopic device used (p > 0.05). Six patients (5%) required reintervention. Following secondary ureterorenoscopy and ureteral drainage with a Mono-J for 6 h, quality of life is independent of stone size and localization, operation time, the treating endourologist, and the URS device used.

Novel Use of a Modified Triangular Prismatic Double-J Stent for 2- to 3-cm Renal Stones after One-Stage Retrograde Intrarenal Surgery

OBJECTIVES

To initially evaluate the outcomes of the modified triangular prismatic double-J (DJ) stent in the management of 2- to 3-cm renal stones after one-stage retrograde intrarenal surgery (RIRS).

METHODS

Patients with 2- to 3-cm renal stones who underwent one-stage RIRS with indwelling DJ stents were retrospectively evaluated. Eighty-eight patients who were placed the triangular prismatic DJ stents and 64 patients who received standard DJ stents were randomly included. The clinical characteristics and intraoperative and postoperative outcomes of the 2 groups were compared and analyzed.

RESULTS

The 2 groups had similar baseline characteristics. The urinary symptom score and pain score did not differ between groups (p > 0.05). The residual fragments of the 2 groups were similar 1 day after operation (p = 0.134). There was no significant difference in residual fragments in the lower calyx between groups at the time of stent removal (p = 0.834). The patients in the modified group had better spontaneous passage of residual fragments in the nonlower calyx than those in the standard group during the 2 weeks with the stents (p = 0.005). Fewer patients in the modified group had residual fragments (>4 mm) in the nonlower calyx (p = 0.026) and ureter (p = 0.010) than the patients with standard stents at the time of stent removal.

CONCLUSION

The indwelling triangular prismatic DJ stent is a safe and efficient treatment method. Patients with these stents had better spontaneous residual fragment passage than those with the standard DJ stents.

Development and Validation of the Stent Tracking Algorithm Registry for Monitoring and Retrieving Forgotten Ureteral Stents

Purpose: Forgotten ureteral stents are associated with safety issues, increased cost, and medicolegal disputes. Tracking ureteral stents is cumbersome because of the variety in placement periods. We developed and validated an electronic medical record (EMR) system-based algorithm for monitoring patients with ureteral stent placements. Materials and Methods: The Stent Tracking Algorithm Registry (STAR) is automatically activated once the physician enters the stent placement or replacement billing code into the EMR billing system. At 120 days, an overdue notification is generated and sent to the attending physician through an EMR pop-up dashboard and e-mail. The model is automatically deactivated when the stent of the corresponding laterality is removed. To validate the feasibility of STAR, we performed a retrospective review of 2194 patients who received stent placements between November 2006 and September 2019. Results: Among 2194 patients, STAR retrospectively identified 354 (16.1%) patients suspected of harboring forgotten ureteral stents. A total of 12 (0.5%) patients actually had forgotten ureteral stents and were contacted for removal. A total of 124 (5.7%) patients were identified because of the omission of the stent removal billing code, whereas 209 (9.5%) patients were identified because of being lost to follow-up after referral to another health care facility or death. There were no cases in which STAR identified patients whose stents were removed or replaced at an appropriate time frame. Conclusions: STAR provides an efficient interface with which to prevent the occurrence of forgotten ureteral stents. This model can be integrated into any EMR system that utilizes coding algorithms.

The effects of pregabalin, solifenacin and their combination therapy on ureteral double-J stent-related symptoms: A randomized controlled clinical trial

Background:

Many medical therapies have been tested to deal with urinary stent-related symptoms (USRS). Several preventive and pharmaceutical methods have been already used for better compatibility of stents. However, the existing evidence for pharmacological treatment is still controversial. This study aims to evaluate the effects of pregabalin, solifenacin, and combination therapy on ureteral double-J stent-related symptoms following ureteroscopy and transureteral lithotripsy (TUL).

Materials and methods:

In a randomized controlled clinical trial, from November 2017 to March 2019, 256 patients who underwent ureteroscopy were enrolled. Patients were randomly divided into four groups including: group A received pregabalin 75mg BID (twice daily), group B received solifenacin 5mg orally once daily, group C received combination of pregabalin and solifenacin and the group D (control) given no drugs.

Results:

One hundred and fifty-one (58.9%) males and 101 (41.1%) females were enrolled in this study with a mean age of 43.47±7 (p=0.32, p=0.67). USSQ domains score such as urinary symptoms, pain, general condition, work performance, sexual matters and additional problems were significantly differenced during second and fourth week of follow-up among study groups (p <0.0001).

In Tukey's multiple comparison test, urinary symptoms (p=0.735), pain (p=0.954) and sexual matters (p=0.080) in second week and work performance in forth week in group B was not significantly better than group D. Only group C in all indexes of USSQ showed significantly beneficial effects over group D (p <0.0001).

Conclusion:

Combination therapy of pregabalin and solifenacin has a significant effect on stent-related symptoms and is preferred over monotherapy of the respected medications.

Are Technology-Driven Mobile Phone Applications (Apps) the New Currency for Digital Stent Registries and Patient Communication: Prospective Outcomes Using Urostentz App

Background

Forgotten ureteral stents (FUS) and stent-related symptoms (SRS) lead to increased postprocedural emergency department visits and add to the psychological and financial burden of the patients.

Purpose

To review the usage and benefits of ureteral stent tracking and symptom monitoring through a single smartphone-based application (App) platform with 2-way clinician-patient communication. This study also compared the features with other smartphone apps used for stent tracking.

Materials and Methods

100 patients were included in this single-center prospective study conducted between September 2019 and December 2019. Patients who had metallic or long-term indwelling stents, noncomprehensible patients, and those not willing to share their data were excluded from the study.

Results

Of 100 patients, 92 downloaded the Urostentz application, and 72 (78.2%) patients answered the pictorial symptom questionnaire. Symptom score analysis suggested that 62 patients (86.1%) had stent-related symptoms of which 3 required readmission and underwent early stent removal. The mean stent duration was 17.2 + 3.5 days (range: 11-23 days), with 69% of patients having their stent removed on the scheduled date and 25% of patients requesting a change of their appointment via the App.

Conclusion

In this study, there was no case of FUS encountered. The "Urostentz" App is a freely available patient safety stent tracking application that provides a secure and simplified interface, which can significantly reduce the incidence of FUS and provide digital remote assistance in the management of stent-related symptoms.

Retrograde intrarenal surgery: Past, present, and future

With the recent technological advancements in endourology, retrograde intrarenal surgery has become a more popular procedure for treatment of urolithiasis. Furthermore, since the introduction of new laser systems and advanced flexible ureteroscopy with miniaturized ureteroscopes, the treatment indications for retrograde intrarenal surgery have expanded to include not only larger renal stones of >2 cm but also upper urinary tract urothelial carcinoma, ureteral stricture, and idiopathic renal hematuria. Clinicians must keep up with these trends and make good use of these technologies in the rapidly changing field of endourology. Simultaneously, we must consider the risk of various complications including thermal injury due to laser use, ureteral injury caused by the ureteral access sheath, and radiation exposure during retrograde intrarenal surgery with fluoroscopic guidance. This review focuses on the past, present, and future of retrograde intrarenal surgery and provides many topics and clinical options for urologists to consider.

Comparison of the Effects of Four Treatment Techniques Commonly Used in Ureteral Stone Treatment on Patients' Daily Physical Functioning: An Observational Randomized-Controlled Study

Objective: To investigate the effect of four different techniques used in the treatment of ureteral stones on patients' daily physical functioning (PF) and quality of life (QoL). Materials and Methods: Patients who underwent ureterorenoscopy (URS)-with or without Double-J stenting (DJS)-and extracorporeal shock wave lithotripsy (SWL) were divided into four groups: Group I: SWL (n = 29), Group II: URS (n = 43), Group III: URS +4.8F DJS (n = 39), Group IV: URS +6F DJS (n = 42), and Group V: Control (n = 30). Short Form-36 (SF-36) was administered to each participant both preoperatively and 14 days after operation. Based on the SF-36 results, the changes in patients' PF and QoL were evaluated. Results: Ureteral stone treatment was performed in 202 patients. Of these, 153 patients who underwent an effective SWL or URS procedure in the first attempt were included in the study. Success rates in the first session were 53.7% (29/54) and 83.8% (124/148) for SWL and URS, respectively (p < 0.001). All the four groups were similar with regard to age, gender, body mass index, stone size, preoperative PF, and QoL. However, although postoperative PF, role limitations due to physical health, and energy/fatigue scores were similar in Group I, III, and IV, they were significantly higher in Group II. No major complication associated with SWL or URS occurred in any patient. However, in Group 2, DJS was inserted in three (7.7%) patients in the early postoperative period (within the first 48 hours) due to renal colic attacks secondary to ureterovesical junction mucosal edema. Conclusion: URS without DJS seems to be the most advantageous technique in the treatment of ureteral stones in terms of daily PF and QoL. However, it should be noted that patients undergoing URS may require postoperative emergency stenting, although rarely.

Biodegradation and Antimicrobial Properties of Zinc Oxide–Polymer Composite Materials for Urinary Stent Applications

Research advancements in the field of urinary stents have mainly been in the selection of materials and coatings to address commonly faced problems of encrustation and bacterial adhesion. In this study, polylactic acid (PLA) and polypropylene (PP) were evaluated with zinc oxide (ZnO) coating to assess its ability to reduce or eliminate the problems of encrustation and bacteria adhesion. PLA and PP films were prepared via twin screw extrusion. ZnO microparticles were prepared using sol-gel hydrothermal synthesis. The as-prepared ZnO microparticles were combined in the form of a functional coating and deposited on both polymer substrates using a doctor blade technique. The ZnO-coated PP and PLA samples as well as their uncoated counterparts were characterized from the physicochemical standpoints, antibacterial and biodegradation properties. The results demonstrated that both the polymers preserved their mechanical and thermal properties after coating with ZnO, which showed a better adhesion on PLA than on PP. Moreover, the ZnO coating successfully enhanced the antibacterial properties with respect to bare PP/PLA substrates. All the samples were investigated after immersion in simulated body fluid and artificial urine. The ZnO layer was completely degraded following 21 days immersion in artificial urine irrespective of the substrate, with encrustations more evident in PP and ZnO-coated PP films than PLA and ZnO-coated PLA films. Overall, the addition of ZnO coating on PLA displayed better adhesion, antibacterial activity and delayed the deposition of encrustations in comparison to PP substrates.

Non-invasive evaluation of obstruction after ureteroscopic stone removal: Role of renal resistive index assessment

OBJECTIVES

The aim of this study is to evaluate prediction of postoperative ureteral obstruction needing ureteral stent insertion by evaluating the resistive index (RI) values and the grade of hydronephrosis.

MATERIAL AND METHODS

A total of 66 adult patients undergoing stentless endoscopic ureteral stone treatment (URS) between January 2018 and January 2019 were included in this prospective study. Preoperative patient and stone characteristics were noted. All patients were evaluated with renal Doppler ultrasonography study to assess degree of hydronephrosis and RI values. A renal Doppler ultrasonography was repeated at postoperative 1st, 3rd and 7th days. Changes in both RI and hydronephrosis levels before and after the procedures were noted. On the postoperative 7th day, patients were divided into two groups including obstructive and non-obstructive cases according to RI values assessed where a RI value of 0.7 was accepted as the cut-off for obstruction. The preoperative and perioperative characteristics of both groups were evaluated in a comparative manner.

RESULTS

The mean patient age was 43.6 ± 1.72 years. Significant improvements were noted in RI and grade of hydronephrosis after the operation. The grade of hydronephrosis and RI values were found to improve more significantly on postoperative 3rd day when compared to the postoperative 7th day (p < 0.01 and p < 0.01). A significant correlation was detected between the grade of hydronephrosis (>grade 2) and obstructive RI values (> 0.7) in each postoperative visits (p: 0.001). RI values (> 0.7) at postoperative seventh days were correlated with larger mean stone size, increased ureteral wall thickness, increased diameter of the ureter proximal to the stone, and longer duration of the operation. Preoperative high-grade hydronephrosis indicated obstructive RI values at postoperative seventh day (p = 0.001) Conclusion: Changes in RI values on Doppler sonography and the grade of hydronephrosis may be a guiding parameter in assessing postoperative ureteral obstruction.

Advancing Toward 3D Printing of Bioresorbable Shape Memory Polymer Stents

Stents have evolved significantly since their introduction to the medical field in the early 1980s, becoming widely used in percutaneous coronary interventions and following nephrological procedures. However, the current commercially available stents do not degrade and remain in the body forever, leading to problems like restenosis in cardiovascular applications or requiring removal procedures in ureteral applications. Efforts to replace metal with resorbable materials have largely been halted after the commercial failure of and safety concerns elicited by Abbott's Absorb stent in 2017. Industry continues to use common polymers such as poly(l-lactide) (PLLA) and polycaprolactone (PCL) for biomedical products, but due to the weak mechanical properties of these bioresorbable materials in comparison to metals, these devices have struggled to accomplish the goals set, increasing risk of thrombosis. 3D printing stents using bioresorbable and shape memory materials could provide a method of patient-personalized production, remove the need for balloon expansion, and limit stent migration, thus bringing a new age of stent technology. The investigation of a range of 3D-printable and bioresorbable shape-memory polymers can provide solutions to the shortcomings of previously explored bioresorbable stents and revitalize the medical device industry efforts into advancing stent technology.

Biomimetic biodegradable Ag@Au nanoparticle-embedded ureteral stent with a constantly renewable contact-killing antimicrobial surface and antibiofilm and extraction-free properties

Urinary tract infections (UTIs) caused by the contamination of the ureteral stent and the pain associated with secondary stent extractions are worldwide problems in the treatment of urinary tract disorders. Here, we reported a biodegradable, long-term antibacterial, and extraction-free ureteral stent with a constantly renewable contact-killing surface and an antibiofilm function achieved by constructing a hyperbranched poly(amide-amine)-capped Ag shell and Au core nanoparticle (Ag@Au NP)-embedded fiber membrane-structured poly(glycolic acid)/poly(lactic-co-glycolic acid) (PGA/PGLA) ureteral stent. The ureteral stent showed fast contact-killing properties, i.e., 5 min for Escherichia coli and 10 min for Staphylococcus aureus, with an inhibition rate higher than 99%. In addition, gradient degradation of PGA/PGLA endowed the stent with a self-cleaning property and long-term antibacterial function by continuous exfoliation of the stent surface, thereby exposing the inner Ag@Au NPs and eliminating adherent bacteria and proteins. Subsequently, in the 16-day in vitro degradation test, the stent showed durable bactericidal activity, less total release of Ag and Au elements (6.7%, ~8 μg), and low cytotoxicity (with a relative growth rate of >80% of L929 cells). In vivo experiments on a farm pig model showed that the stent exhibited a remarkable antibiofilm property and reduced the level of inflammatory and necrotic cells. After seven days of implantation, the stent showed a gradient degradation behavior and maintained structural integrity without the presence of any large fragments in the urinary system according to the B-ultrasonic examination. The as-developed biodegradable and renewable contact-killing antibacterial strategy was efficient in preparing the ureteral stent with antibiofilm and extraction-free properties to treat stent-induced UTI. Statement of significance This study presents a customized antibiofilm solution for biodegradable implants. Two particularly important aspects of this work are as follows.

Transient stent placement versus tubeless procedure after ureteroscopy retrograde surgery stone extraction (Fast Track Stent study 2): A randomized prospective evaluation

OBJECTIVES

To determine whether in pre-stented patients undergoing ureteroscopic stone removal (ureteroscopy retrograde surgery) a tubeless procedure provides a better outcome compared with short-term (6 h) ureteral stenting using an external ureteral catheter.

METHODS

In this single academic center study (Fast Track Stent study 2), carried out between May 2016 and April 2018, 121 patients with renal or ureteral calculi were initially treated with double-J insertion. Before secondary ureteroscopy retrograde surgery, patients were prospectively randomized into two groups: tubeless versus ureteral catheter insertion for 6 h after ureteroscopy retrograde surgery. Exclusion criteria were acute urinary tract infection, solitary kidney or stone diameter >25 mm. Study end-points were stent-related symptoms assessed by a validated questionnaire (ureteral stent symptom questionnaire), administered both before and 4 weeks after surgery. Numerical ureteral stent symptom questionnaire scores were compared using the Mann-Whitney-U-test. The level of significance was defined as P < 0.05.

RESULTS

Ureteroscopy retrograde surgery procedures carried out by 13 surgeons resulted in >90% stone removal in all patients (n = 121), with a mean operation time of 19.9 versus 18.0 min for ureteral catheter versus tubeless, respectively (P = 0.37). Patient groups did not differ significantly in their ureteral stent symptom questionnaire scores (urinary index P = 0.24; pain index P = 0.35). Patients showed a significant preference for tubeless procedure over ureteral catheter reinsertion (Question GQ P < 0.0001). The reintervention rate was 13.3% for the tubeless procedure (n = 8) and 1.6% for the ureteral catheter group (n = 1), respectively (P = 0.034).

CONCLUSIONS

Short-term ureteral catheter and no stent insertion after ureteroscopy retrograde surgery stone extraction in pre-stented patients result in comparable quality of life. However, the reintervention rate is higher for tubeless procedures.

Urinary tract infection and antibiotic use around ureteral stent insertion for urolithiasis

Urolithiasis is the main indication for a ureteral JJ stent. Our aim was to determine the incidence of urinary tract infections (UTIs) after a JJ stent for urolithiasis, with an emphasis on antibiotic use. Prospective, multicenter, cohort study over a 4-month period including all of the patients with urolithiasis requiring JJ stent insertion. The clinical and microbiological data and therapeutic information were recorded until removal of the JJ stent. Two hundred twenty-three patients at five French private hospitals were included. A urine culture was performed for 187 patients (84%) prior to insertion of a JJ stent, 36 (19%) of which were positive. One hundred thirty patients (58%) received an antibiotic therapy during surgery: 74 (33%) prophylaxis and 56 (25%) empirical antibiotic therapy, comprising 17 different regimens. The rate of prophylaxis varied according to the center, from 0 to 70%. A total of 208 patients were followed-up until removal of the first stent. The rate of UTIs was 6.3% (13/208); 8.1% of the patients who did not receive a prophylaxis had a UTI versus 1.4% of those who did receive a prophylaxis (p = 0.057). Seven empirical antibiotic regimens were used to treat these 13 patients. Another large panel of antibiotic prescriptions was observed at the time of JJ stent removal. The incidence of a UTI after JJ stent insertion for urolithiasis was 6.3%, in part due to a lack of prophylaxis. An unwarranted diversity of antibiotic use was observed at each step of care.

Numerical Analysis of Urine Flow with Multiple Sizes of Double-J Stents

This study investigated which sizes of double-J stents are more effective in achieving an acceptable urine flow through stenotic and stented ureters. Sixty four computational fluid dynamics models of the combinations of two different gauge ureters (4.57 mm and 5.39 mm in diameter) with four different levels of ureteral and four different sizes of double-J stents were developed for the numerical analysis of urine flow in the ureter. Luminal, extraluminal, and total flow rates along the ureter were measured, and the flow patterns around the ports and side holes were investigated. For the 4.57-mm ureter, the total flow rate for each gauge of stent was 23–63 mL/h (5 Fr), 20–47 mL/h (6 Fr), 17–35 mL/h (7 Fr), and 16–26 mL/h (8 Fr) and for the 5.39-mm ureter, the total flow rate for each gauge of stent was 43–147 mL/h (5 Fr), 36–116 mL/h (6 Fr), 29–92 mL/h (7 Fr), and 26–71 mL/h (8 Fr). With a 74% stenosis, all stents allowed a low flow rate, and the differences in flow rates between the stents were small. At the other levels of stenosis, 5 Fr stents allowed greater flow rates than the 8 Fr stents. The luminal flow rate increased just before the area of stenosis and decreased after the stenosis because of the increase and decrease in the luminal flow through the side holes before and after the stenosis. Therefore, a larger double-J stent is not favorable in achieving an acceptable urine flow through the stenotic and stented ureters. The results in this study could not be necessarily correlated with clinical situation because peristalsis, viscosity of the urine and real format of the ureter were not considered in our model. In vivo experiments are necessary for confirmation of our findings. Double J stents are commonly used in the ureteral stenosis or occlusion, especially due to ureter stones which obstruct the flow of urine. Clinicians choose the size of double J stent on the basis of their clinical experience. Here, we tried to know which sizes of double J stents are better for sufficient urine flow. According to various documents that try to determine the optimal shape of double J stents to increase the urine flow through the ureter, mostly bigger stent is recommended to occur maximum urine flow. However, in case of ureter with stenosis or occlusion, the right size of the double J stent may vary depending on the degree of stenosis in the ureter. To find appropriate stent size for the ureter with stenosis, computational fluid dynamics was conducted. This study shows that smaller diameter stents are more appropriate than larger diameter stents depending on the situation.

Semirigid Ureteroscopy: Step by Step

This article aims to demonstrate a step-by-step technique of semirigid ureteroscopy (URS) for the treatment of ureteral stones, urothelial tumors, and ureteral stenosis. Operating room setup, camera settings, access to the bladder, and negotiation of the ureteral orifice, lasertripsy, basketing of the stone fragments, endoscopic treatment of ureteral tumors and ureteral stenosis, flexible URS at the end of semirigid URS, and Double-J stent placement are described step by step.

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.

Development and internal validation of a nomogram to predict perioperative complications after flexible ureteroscopy for renal stones in overnight ureteral catheterization cases

PURPOSE

To identify risk factors by developing and internally validating a nomogram for preventing perioperative complications in overnight ureteral catheterization cases after fURS for kidney stones.

METHODS

We retrospectively examined 309 patients with overnight ureteral catheterization after single fURS procedures for renal stones. fURS procedures were performed based on the fragmentation technique. The ureteral catheter was removed on postoperative day 1. Within this group, patients who experienced perioperative complications (complication group) were compared with those who did not experience complications (non-complication group). The complication group included 77 patients whose Clavien-Dindo classification score was I, II, III, or IV and/or those whose body temperature during hospitalization was over 37.5 °C.

RESULTS

The overall stone volume, stone-free rate, incidence of perioperative complications, and procedure duration were 1.39 mL, 94.8%, 24.9%, and 62 min, respectively. Severe complications of a Clavien-Dindo level III or IV were observed in only four cases (1.3%). Multivariate assessment revealed five independent predictors of perioperative complications after fURS with overnight catheterization: age (p = 0.11), sex (p = 0.067), stone volume (p = 0.33), Hounsfield units (p = 0.16), and narrow ureter (p = 0.018). We developed a nomogram to predict perioperative complications after fURS using these parameters.

CONCLUSIONS

We developed a predictive model for perioperative complications of patients with overnight catheterization after fURS for renal stones. This model could select patients who were at a low risk of complications.

Indications for stent omission after ureteroscopic lithotripsy defined: A single-institution experience with cost analysis

Objectives: To report on our experience with the use of an evidence-based algorithm defining specific indications for stent omission (SO) after ureteroscopic lithotripsy (URSL), as stent placement has been associated with increased cost and morbidity and indications for SO in the setting of uncomplicated ureteroscopy have been proposed but remain vague.

Patients and methods: Indications for SO were defined as per the attached figure, data from URSL procedures performed from January 2016 to September 2017 were collected. For procedures eligible for SO, preoperative and intraoperative factors were recorded including: stone burden, presence of preoperative stent, procedure time, access sheath use, and whether SO was performed. Morbidity data were reviewed including: postoperative events, patient telephone calls for bothersome symptoms, unplanned return visits, and admissions within 30 days.

Results: In all, 250 URSL procedures were performed during the study period, and 106 (42.4%) were eligible for SO. SO was performed in 60 (24.0%) cases reflecting a 56.7% compliance with the algorithm. There were no readmissions or re-operations within 30 days for the SO group. Lower postoperative event rates were noted in the SO group (16.7% vs 34.8%, P = 0.03), unplanned return visits (8.3% vs 17.4%, P = 0.16) and 30-day readmission rates (0.0% vs 6.5%, P = 0.08) were also lower in the SO group, although they did not reach statistical significance. Analysis also demonstrated a protective effect of SO on unplanned return visits (odds ratio 0.43, 95% confidence interval 0.13–1.42, P = 0.17), although this was not statistically significant. No statistically significant associations were noted between postoperative events and stone burden, procedure time, or presence of preoperative stent.

Conclusions: We provide an algorithm defining indications for SO. SO is safe in a significant portion of URSL procedures, and SO appears to decrease postoperative events when performed judiciously.

Abbreviations: IQR: interquartile range; LUTS: lower urinary tract symptoms; OR, odds ratio; SO: stent omission; URSL: ureteroscopic lithotripsy; YAG: yttrium-aluminium-garnet

The Efficacy of Ultra-thin Semi-rigid Ureteroscopy with Holmium Laser Lithotripsy in Pediatric Ureteral Stones: A Single-center Experience

Introduction

The aim of this study was to present our results regarding the feasibility and possible complications of 4.5 Fr semi-rigid ureterorenoscopy (URS) treatments in pediatric patients.

Methods

The files and computer records of a total of 33 pediatric patients (20 males and 13 females), who underwent URS procedures for ureteral stones > 5 mm between January 2013 and June 2017, were retrospectively reviewed. A 4.5 Fr semi-rigid ureteroscope (Ultrathin 4.5/6.5 Fr Ureterorenoscope; Richard Wolf GmbH, Knittlingen, Germany) was used for the URS procedures. For the stone-free rate evaluations, abdominopelvic ultrasound or direct radiography scans were performed one week after the surgery, and low-dose non-contrast computed tomography (CT) was performed during the first month.

Results

The mean age of the patients was 9.8 ± 2.8 (range 4-16) years old, and the mean ureteral stone size was 8.9 ± 1.4 (range 6-13) mm. The mean surgical duration was 45 ± 21.2 (range 30-75) minutes, and the mean hospital stay length was 1.2 (range 1-4) days. Minor complications occurred in five (15.1%) of the patients. The success rates for the first week and first month were 90.9% and 96.9%, respectively.

Conclusion

The endoscopic management of pediatric ureteral stones using a 4.5 Fr ureteroscope seems to be a safe and feasible treatment option with high success and low complication rates.

Reprint - Ureteral stent vs. no ureteral stent for ureteroscopy in the management of renal and ureteral calculi: A Cochrane review

INTRODUCTION

We aimed to assess the effects of postoperative ureteral stent placement after uncomplicated ureteroscopy.

METHODS

We performed a comprehensive search with no restrictions on publication language or status up to February 1, 2019. We only included randomized trials. Two review authors independently examined full-text reports, identified relevant studies, assessed the eligibility of studies for inclusion, extracted data, and assessed risk of bias. We performed statistical analyses using a random-effects model and assessed the certainty of the evidence according to GRADE.

RESULTS

We included 23 studies with 2656 randomized patients. Primary outcomes: It is uncertain whether stenting reduces the number of unplanned return visits (very low certainty of evidence [CoE]). Pain on the day of surgery is probably similar (mean difference [MD] 0.32; 95% confidence interval (CI) -0.13-0.78; moderate CoE). Pain on postoperative days 1-3 may show little to no difference (standardized mean difference [SMD] 0.25; 95% CI -0.32-0.82; low CoE). It is uncertain whether stented patients experience more pain on postoperative days 4-30 (very low CoE). Stenting may result in little to no difference in the need for secondary interventions (risk ratio [RR] 1.15; 95% CI 0.39-3.33; low CoE).

SECONDARY OUTCOMES

We are uncertain whether stenting reduces the need for narcotics and reduces ureteral stricture rates up to 90 days (very low CoE). Rates of hospital admission may be slightly reduced (RR 0.70; 95% CI 0.32-1.55; low CoE). This review was limited to patients in whom ureteroscopy was deemed 'uncomplicated.' In addition, time intervals for the grouping for the reported degree of pain were established post-hoc. The CoE for most outcomes was rated as low or very low for methodological reasons.

CONCLUSIONS

Findings of this review illustrate the tradeoffs of risks and benefits faced by urologists and their patients when it comes to decision-making about stent placement after uncomplicated ureteroscopy for stone disease.

Pyelolithotomy in a Patient with Complete Coraliform Calcification Induced by a Double-J Ureteral Stent

The placement of a double-J ureteral stent enables the treatment of upper urinary tract obstruction. Despite advances, forgetting the stent favors the occurrence of calcification, leading to increased morbidity rates, lawsuits, and a financial burden on the healthcare system. This paper describes a successful pyelolithotomy for the removal of a calcified double-J ureteral stent.

Ureteral stent versus no ureteral stent for ureteroscopy in the management of renal and ureteral calculi

BACKGROUND

Ureteroscopy combined with laser stone fragmentation and basketing is a common approach for managing renal and ureteral stones. This procedure is associated with some degree of ureteral trauma. Ureteral trauma may lead to swelling, ureteral obstruction, and flank pain and may require subsequent interventions such as hospital admission or secondary ureteral stent placement. To prevent such issues, urologists often place temporary ureteral stents prophylactically, but the value of doing so remains unclear.

OBJECTIVES

To assess the effects of postoperative ureteral stent placement after uncomplicated ureteroscopy.

SEARCH METHODS

We performed a comprehensive search using multiple databases (the Cochrane Library, MEDLINE, Embase, Scopus, Google Scholar, and Web of Science), trials registries, other sources of grey literature, and conference proceedings, up to 01 February 2019. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included trials in which researchers randomised participants undergoing uncomplicated ureteroscopy to placement of a ureteral stent versus no ureteral stent.

DATA COLLECTION AND ANALYSIS

Two review authors independently classified studies and abstracted data from the included studies. We performed statistical analyses using a random-effects model. We rated the certainty of evidence (CoE) according to the GRADE approach.

MAIN RESULTS

Primary outcomesStenting may slightly reduce the number of unplanned return visits (16 trials with 1970 participants; very low CoE), but we are very uncertain of this finding.Pain on the day of surgery as measured on a visual analogue scale (scale 0 to 10; higher values reflect more pain) is probably similar (mean difference (MD) 0.32 higher, 95% confidence interval (CI) 0.13 lower to 0.78 higher; 4 trials with 346 participants; moderate CoE). Pain on postoperative days 1 to 3 may show little to no difference (standardised mean difference (SMD) 0.25 higher, 95% CI 0.32 lower to 0.82 higher; 8 trials with 683 participants; low CoE). On postoperative days 4 to 30, stented participants may experience more pain (8 trials with 903 participants; very low CoE), but we are very uncertain of this finding.Stenting may result in little to no difference in the need for secondary interventions (risk ratio (RR) 1.15, 95% CI 0.39 to 3.33; 10 studies with 1435 participants; low CoE); this corresponds to three more interventions per 1000 participants (95% CI 13 fewer to 48 more).Secondary outcomesStenting may reduce the need for narcotics (7 trials with 830 participants; very low CoE), but we are very uncertain of this finding.Rates of urinary tract infection (UTI) up to 90 days are probably not substantially different (RR 0.94, 95% CI 0.59 to 1.51; 10 trials with 1207 participants; moderate CoE); this corresponds to three fewer infections per 1000 participants (95% CI 23 fewer to 29 more).Ureteral stricture rates up to 90 days may be slightly reduced (14 trials with 1625 participants; very low CoE), but we are very uncertain of this finding.Rates of hospital admission may be slightly reduced (RR 0.70, 95% CI 0.32 to 1.55; 13 studies with 1647 participants; low CoE). This corresponds to 15 fewer admissions per 1000 participants (95% CI 33 fewer to 27 more).

AUTHORS' CONCLUSIONS

Findings of this review illustrate the trade-offs of risks and benefits faced by urologists and their patients when it comes to decision-making about stent placement after uncomplicated ureteroscopy for stone disease. We noted that both desirable and undesirable effects were small in absolute terms, with findings based mostly on low and very low CoE. The main issues reducing our confidence in research findings were study limitations (mostly risk of performance and detection bias) and imprecision. We were unable to conduct any of the preplanned subgroup analyses, in particular those based on stone size, stone location, and use of ureteral dilation, which may be important effect modifiers. Given the importance of this question, higher-quality and sufficiently large trials are needed to better inform decision-making.

Reducing deposition of encrustation in ureteric stents by changing the stent architecture: A microfluidic-based investigation

Ureteric stents are clinically deployed to retain ureteral patency in the presence of an obstruction of the ureter lumen. Despite the fact that multiple stent designs have been researched in recent years, encrustation and biofilm-associated infections remain significant complications of ureteral stenting, potentially leading to the functional failure of the stent. It has been suggested that "inactive" side-holes of stents may act as anchoring sites for encrusting crystals, as they are associated with low wall shear stress (WSS) levels. Obstruction of side-holes due to encrustation is particularly detrimental to the function of the stent, since holes provide a path for urine to by-pass the occlusion. Therefore, there is an unmet need to develop novel stents to reduce deposition of encrusting particles at side-holes. In this study, we employed a stent-on-chip microfluidic model of the stented and occluded ureter to investigate the effect of stent architecture on WSS distribution and encrustation over its surface. Variations in the stent geometry encompassed (i) the wall thickness and (ii) the shape of side-holes. Stent thickness was varied in the range 0.3-0.7 mm, while streamlined side-holes of triangular shape were evaluated (with a vertex angle in the range 45°-120°). Reducing the thickness of the stent increased WSS and thus reduced the encrustation rate at side-holes. A further improvement in performance was achieved by using side-holes with a triangular shape; notably, a 45° vertex angle showed superior performance compared to other angles investigated, resulting in a significant increase in WSS within "inactive" side-holes. In conclusion, combining the optimal stent thickness (0.3 mm) and hole vertex angle (45°) resulted in a ∼90% reduction in encrustation rate within side-holes, compared to a standard design. If translated to a full-scale ureteric stent, this optimised architecture has the potential for significantly increasing the stent lifetime while reducing clinical complications.

The Impact of Technique Standardization on Total Operating and Fluoroscopy Times in Simple Endourological Procedures: A Prospective Study

PURPOSE

To present the positive impact of technique standardization on successful outcome, fluoroscopy, and total operating time (TOT) shortening in a prospective study.

METHODS

Six experienced endourologists participated. To assess whether the adaptation of standardized surgical steps improved their methodology with time, 253 patients were prospectively divided in three consecutive 1-month groups. Patients underwent stent placement and exchange and total operating and fluoroscopy times (FTs) were recorded. All surgeons were unaware of their mean recorded results until the end of the study. At the end of the third month, we evaluated if the suggested technique standardization established a decrease for both FT and TOT. Statistical significance was set to p < 0.05.

RESULTS

Total operating and FTs were significantly reduced with time between all groups of patients. For stent placement, TOT showed significant reduction between Groups A and C (p < 0.001), while between other group comparisons did not reach significance. FT showed a significant reduction (p < 0.001) in all group comparisons. For stent exchange, TOT reached significant improvement (p = 0.003) between Groups A and C, whereas between other groups was insignificant. FT improvement was significant between Groups A and C (p < 0.001) and Groups B and C (p < 0.001), but insignificant between Groups A and B.

CONCLUSIONS

Even in experienced hands, the adaptation of technique standardization results in significant decrease of total operating and FTs and it is independent from feedback regarding their time performance.

The use of a string with a stent for self-removal following ureteroscopy: A safe practice to remain

Abstract objectives

To examine the safety and effectiveness of the use of a stent with a string attached after ureteroscopy (URS) for self-removal of the stent by the patient.

Patients and methods

After Institutional Review Board approval, a retrospective chart review was performed concerning patients who underwent URS and received an indwelling stent with or without a string attached to the stent (94 vs 349, respectively). Amongst the string group patients received a single- or a double-arm-stringed stent (31 vs 63, respectively). Statistical analyses included chi-squared and Student’s t-tests.

Results

The string group consisted of 94 procedures, in which 59.6% of the patients were male with a mean (SD) age of 50.0 (16.5) years. In the no-string group, 51.3% of the 349 procedures were performed in males and the mean (SD) age was 54.9 (18.1) years. Complication rates were 12.8% in the string group and 14.0% in the no-string group (P = 0.867). In the string group, 17.0% of the patients returned to the Emergency Department, whilst 15.8% of the no-string patients returned (P = 0.753). The complication rate in the single- and double-arm groups were 12.9% and 12.7%, respectively (P > 0.910). Self-removal of stents was successful in 94.7% of patients (89/94).

Conclusions

The use of a stent with a string after URS appears safe and effective. Few patients had difficulty removing their stents and complication rates were similar in the groups with and without a string attached to their stents. Single- and double-arm-stringed stents have similar complication rates.

How bothersome double-J ureteral stents are after semirigid and flexible ureteroscopy: a prospective single-institution observational study

PURPOSE

To evaluate in details the actual extent of double-J stent-related symptoms after semirigid (URS) and flexible (RIRS) ureteroscopy using a validated questionnaire.

METHODS

We asked to complete the Ureteric Stent Symptoms Questionnaire (USSQ) to all stone patients undergoing URS or RIRS with stent placement from 2010 to 2015. Stent-related symptoms' prevalence, severity, and impact on daily life were analyzed using descriptive statistics and five-order Likert scales. Subgroups analyses were performed.

RESULTS

232 patients completed the USSQ. Stents had a deep impact on urinary symptoms (daily frequency ≥ 1 per hour 59.1%, ≥ 1 nocturnal micturition 90.1%, urgency 86.6%, burning 82.3%) that represented a problem for 88.4% of patients. 83.2% complained of pain, mostly in the kidney (67.9%) or in the bladder area (31.3%), particularly during physical activity (72.9%) and micturition (77.0%). Pain interfered with everyday life in 92.2%. General health, working, and sexual activity were also affected. 62.0% of patients would be dissatisfied (51.6% unhappy or terrible) if further ureteral stenting was proposed in future. Younger patients and females were more affected. Limitations include observational design and lack of baseline evaluation.

CONCLUSIONS

Ureteral stents are responsible for significant urinary symptoms and pain after semirigid and flexible ureteroscopy. They also considerably affect general health, working and sexual activity. Urologists should consider it carefully before stenting, inform patients about stent-related symptoms, and minimize stent indwelling time.