Ureteral Stent-Associated Pain: A Review

Outcomes of a non-randomised audit of single pigtail suture stents in urolithiasis management of Asian patients in Singapore

Objective

Double-J (DJ) ureteric stents are commonly placed perioperatively for semirigid or flexible ureteroscopic renal surgery. It is believed that lesser stent material within the bladder mitigates stent-related symptoms. This study aimed to evaluate the J-Fil ureteral stent, a single pigtail suture stent compared with conventional DJ stent in relation to stent symptoms in an Asian population undergoing ureterorenal intervention.

Methods

Based on internal audit committee recommendation approval, the records of 50 patients retrieved, available data of 41 patients who were prospectively enrolled into two groups (Group 1 [J-Fil stent group], n=21 and Group 2 [DJ stent group], n=20) between August 2020 to January 2021, were analysed. Parameters compared were nature of procedure, stone location and size, ease of deployment or removal, and complications. A modified universal stent symptom questionnaire was used to assess morbidity of stent symptoms within 48 h of insertion and at removal.

Results

Both groups had similar median age, distribution in male to female ratio, and stone size. The overall median universal stent symptom questionnaire score at insertion was similar for bladder pain, flank or loin pain, and quality of life between Group 1 and 2; however, at removal Group 1 fared significantly better than Group 2, especially for flank or loin pain and pain at voiding. Both groups had similar ease in insertion with no hospital readmissions.

Conclusion

Our audit favoured the single pigtail suture stent in Asian ureters in mitigating stent-related issues. It showed a good safety profile with easy deployment and removal. It promises a new standard in stenting.

Antireflux Ureteral Stents Prevent Stent-Related Symptoms: A Meta-Analysis of Randomized Controlled Trials

Ureteral stents are widely used in urological care, but they are often associated with adverse stent-related symptoms (SRS), such as painful urination, elevated urinary frequency, and abdominal discomfort. Antireflux ureteral stents have been developed to reduce stent-related pain and reflux by minimizing vesicoureteral reflux (VUR). This systematic review and meta-analysis of randomized controlled trials (RCTs) was undertaken to assess the efficacy of antireflux ureteral stents in mitigating SRS compared to conventional urethral stents. Our study included a total of 269 cases from three RCTs. The meta-analysis showed that antireflux ureteral stents were significantly more effective than standard stents in reducing SRS, including stent-related pain (odds ratio (OR): 4.80, 95% CI: 2.77, 8.31, p <0.00001), severe stent-related pain (OR: 8.35, 95% CI: 2.12, 32.89, p=0.002), flank pain while urinating (OR: 5.98, 95% CI: 3.35, 10.68, p <0.00001), and severe flank pain while urinating (OR: 15.79, 95% CI: 2.91, 85.57, p=0.001). There was no significant difference in the rates of postoperative creatinine abnormality or postoperative hydronephrosis between the two groups. Therefore, antireflux ureteral stents are more effective than standard stents in reducing SRS. This suggests that antireflux ureteral stents should be considered for patients undergoing ureteral stenting.

Epidemiology and risk factors for febrile ureteral stent-associated urinary tract infections: A prospective observational cohort study

OBJECTIVES

We aimed to determine the incidence and risk factors of febrile ureteral stent-associated urinary tract infections (FUSAUTI).

METHODS

Hospitalized adult patients with ureteral stent (US) placement or exchange were prospectively enrolled. Patients with kidney transplantation of less than one year were excluded. Patients were followed until US removal/exchange or six months after inclusion.

RESULTS

Out of 663 patients included in the study, 48 had at least one FUSAUTI (cumulative incidence 7.24%; 95% confidence interval [CI] 5.39-9.48). The incidence rate of FUSAUTI was 9.04 (95% CI 6.67-12.2) per 10,000 US-days. Ten patients (20.8%) experienced sepsis or septic shock. The most frequently isolated microorganisms were Escherichia coli (38%), Enterococcus spp. (14.5%), Candida spp. (9%) and Pseudomonas aeruginosa (9%). In multivariable logistic regression analysis, female gender, an age adjusted Charlson comorbidity index score> 3, an urethral stent placement concomitant with US placement, and a history of urinary tract infection within three months were significantly associated with a higher risk of FUSAUTI.

CONCLUSION

After US placement, 7.24% of patients developed at least one FUSAUTI and, in a quarter of cases, a serious infection. Urethral stent placement was the only modifiable risk factor identified. Future interventional studies are needed to reduce FUSAUTI in these patients.

Indwelling stents cause severe inflammation and fibrosis of the ureter via urothelial-mesenchymal transition

To explore the pathways and mechanisms driving inflammation and fibrosis in stented ureters. In total, six healthy female pigs underwent cystoscopic unilateral ureteral stent insertion (6 Fr). After 14 days indwelling time, ureteral tissue was harvested in three pigs, while the remaining three pigs had their stents removed, and were recovered for 7 days. Three separate pigs served as controls. Tissue from stented and contralateral ureters was analysed histologically to evaluate tissue remodelling and classify the degree of inflammation and fibrosis, while genome, proteome and immunohistochemistry analysis was performed to assess changes at the transcriptional and translational levels. Finally, immunofluorescence was used to characterize the cell composition of the immune response and pathways involved in inflammation and fibrosis. Statistical analysis was performed using GraphPad Prism and RStudio for Welch ANOVA, Kruskal-Wallis and Dunnett's T3 multiple comparison test. Stents cause significant inflammation and fibrosis of ureters. Gene set enrichment analysis confirmed fibrotic changes and tissue proliferation and suggests that epithelial-mesenchymal transition is a driver of fibrosis. Moreover, IL-6/JAK/STAT and TNFα via NF-κB signalling might contribute to chronic inflammation promoting a profibrotic environment. Immunostaining confirmed epithelial-mesenchymal transition in the urothelium and NF-κB expression in ureters stented for 14 days. Tissue alterations do not fully recover after 7 days. Histological evaluation showed that contralateral, unstented ureters are affected by mild inflammation. Our study showed that stenting has a significant impact on the ureter. Chronic inflammation and epithelial-mesenchymal transition are drivers of fibrosis, potentially impairing ureteral functionality in the long term. Furthermore, we observed mild inflammation in contralateral, unstented ureters.

Active stone removal is a safe option for ocotogenarians and nonagenarians with nephrolithiasis

PURPOSE

To assess the contemporary in-hospital management of octogenarians and nonagenarians with renal calculi.

MATERIAL AND METHODS

A multicentric retrospective evaluation of patients aged ≥ 80 years hospitalized with kidney stones between 01/2000 and 12/2019. Stone and patient related data were collected, including stone size and location, geriatric status and comorbidities. Surgical treatment patterns and outcome were assessed.

RESULTS

A total of 299 patients (57% female) with kidney stones were analyzed. Mean age was 84.7 years. Patients were largely multimorbid (ASA ≥ 3 in 70%) and about 25% were classified as frail. Active stone treatment was performed in 65% and 35% were treated with urinary diversion (stent or nephrostomy). Prognostic factors for receiving an active stone treatment were age < 90 years, male sex, stone size and quantity, and performance status. Mean overall survival was 23.7 months and when stratified to treatment mean survival were 21 months after urinary diversion, 28 months after URS, 29 months after PCNL and 45 months after SWL.

CONCLUSION

Age, frailty and performance-status as well as stone size and quantity are predictors for active stone treatment. Octogenarians and nonagenarians, who are considered fit for surgery, tend to live long enough to profit from active stone treatment.

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

Context

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

Objective

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

Evidence acquisition

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

Evidence synthesis

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

Conclusions

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

Patient summary

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

Reduction of pre-procedural anxiety for repeat sessions in extracorporeal shockwave lithotripsy (ESWL) reduces pain intensity: A prospective observational study

Pain control is a major determinant for successful stone clearance in extracorporeal shockwave lithotripsy (ESWL) for urolithiasis. Pain perception during ESWL may be influenced by patient factors like gender, age, body habitus and anxiety level, and stone related factors like size, laterality and location of stone. We investigated in general, the confounding patient and stone factors influencing pain perception during ESWL with importance given to procedural anxiety in first and the subsequent session of ESWL. This was a prospective observational study of all new consecutive patients who underwent ESWL for a period of 1 year at a tertiary Urological Centre. Demographic and stone anthropometry were analyzed. Pre-procedural anxiety was assessed prior to procedure using hospital anxiety and depression score (HADS) and pain was scored using numerical rating scale-11 at baseline, 30-minutes (i.e., during) and 24 hours after ESWL. Univariate and multivariate analysis for confounding factors included HADs were performed for pain perception. A P value < .05 was considered to be statistically significant. For the study duration, 119 patients were recruited and 72 of them returned for a second session. Procedural anxiety was the only independent factor affecting pain score in ESWL for the first session in multivariate analysis. A statistically significant reduction of mean procedural anxiety score from 6.7 ± 4.5 to 3.2 ± 2.7 (P < .05) for the second ESWL session was observed (n = 72). This was in conjunction with statistical reduction of mean pain score 30 minutes after ESWL from 5.2 ± 2.1 to 4.2 ± 2.1 (P < .05). Patients with HADS ≥ 8 had statistically significant higher mean pain score at all 3 intervals in the first ESWL session. This study has shown that pre-procedural anxiety mainly anticipatory, reduces and shows reduction in pain intensity among patients undergoing repeat ESWL. Hence, anxiety reducing methods should be explored in patients undergoing ESWL to avoid unnecessary analgesic use.

The Function Improved of the Newly Designed Magnetic-End Ureteric Stenting Retrieval Device: A Clinical Prospective Randomized and Control Trial in a Multicenter Study

Objective

To demonstrate the advantage of our newly designed magnetic ureteric stenting retrieval device over traditional nonmagnetic ureteric stents and other retrieval devices without cystoscopy intervention on clinical application and cost-related outcomes. Patients and Methods. A total of 333 patients were recruited into two study groups: magnetic-end ureteral stent (Group A) and conventional ureteral stent (Group B). The effects were evaluated by Ureteral Stent Symptom Questionnaire (USSQ) scores, complications of the indwelling stent, visual analog scale (VAS) pain scores at stent removal, and cost-analysis outcomes between the magnetic ureteric stenting retrieval device and traditional double-J ureteral stent (DJUS) removed by cystoscopy.

Results

The VAS of the pain score of patients undergoing magnetic stent removal with the retrieval device was 2 ± 0.97, whereas that of patients undergoing conventional ureteral stent removal with cystoscopy was 5.76 ± 1.53 (p < 0.001). The removal of magnetic stents by a retrieval device proved to be less painful than cystoscopy-mediated stent removal (p < 0.001). Obviously, the total cost for the magnetic stent removal was much lower than the conventional ureteral stent removal, although the magnetic stent costs more than the conventional ureteral stent. The improved magnetic stent used in our study showed a remarkable cost saving of 705/111 USD Chinese Yuan (CNY) per patient when compared with the conventional ureteral stent.

Conclusion

We reported the integrated design features of the improved magnetic stent in the world, which was granted a patent in China. USSQ scores and rate of complications in the magnetic stent were as equally acceptable as a conventional stent. Furthermore, successful stent insertion rate reached 100% by both the antegrade and retrograde approaches, and no failure case of magnetic stent removal was reported in our study.

Transperitoneal laparoscopic ureteropyeloplasty of retrocaval ureter: Single surgeon experience and review of literature

INTRODUCTION

Retrocaval ureter (RCU) is a rare congenital abnormality, secondary to anomalous development of inferior vena cava (IVC) presenting as ipsilateral obstruction needing surgical intervention. The aim of this article is to present surgical techniques and outcome of transperitoneal laparoscopic ureteropyeloplasty in patients with RCU treated by a single surgeon at a tertiary care center and with review of literature.

MATERIAL AND METHODS

We conducted a retrospective, institutional review board approved chart review of patients who underwent transperitoneal laparoscopic ureteropyeloplasty for RCU at our unit between January 2010 and December 2020. A total of 10 patients were identified. Preoperative evaluation involved a computed tomography-intravenous urography in addition to the conventional evaluation. All the patients underwent dismembered transperitoneal laparoscopic ureteropyeloplasty over a Double J stent. Data analyzed included the demographic profile, operative time difficulty if any, postoperative, intraoperative complications and functional outcome.

RESULTS

All cases were completed laparoscopically and no open conversion was required. Average operating time was 96.6 minutes ± 8.16. Average blood loss was 71 ± 14.49 mL with an analgesia requirement of 115 ± 33.74 mg. One patient developed postoperative urinary leak and responded to percutaneous nephrostomy drainage. Patients were followed up for 3 to 12 months with a serial ultrasound and a follow-up diethylene-triamine-penta-acetic acid renal scan at 3 months to rule out any anastomotic site obstruction.

CONCLUSION

Transperitoneal laparoscopic ureteropyeloplasty for RCU was associated with minimal morbidity and good outcomes.

The efficacy and safety of mirabegron in treating ureteral stent-related symptoms: A systematic review and meta-analysis

OBJECTIVES

This meta-analysis aimed to assess the efficacy and safety of mirabegron in treating ureteral stent-related symptoms.

METHODS

MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched to identify randomized controlled trials (RCT) of mirabegron in treating ureteral stent-related symptoms. We conducted a systematic review and meta-analysis based on the eligible RCT.

RESULTS

Five RCT including 546 patients and comparing mirabegron with placebo or blank control were involved in the present research. Regarding efficacy, mirabegron was superior to controls in urinary symptom score (P = .0006) and general health score (P < .0001) of the Ureteral Stent Symptom Questionnaire, total International Prostate Symptom Score (P < .00001), quality of life (P < .0001), analgesic use (P = .008), and readmission or visit to hospital due to discomfort (P = .001). Safety assessments including adverse events (P = .40) suggested that mirabegron was well tolerated.

CONCLUSIONS

The present meta-analysis shows that mirabegron is an effective and safe treatment for relieving ureteral stent-related symptoms with a low occurrence of adverse events.

Assessment of encrustation and physicochemical properties of poly(lactide-glycolide) - Papaverine hydrochloride coating on ureteral double-J stents after long-term flow of artificial urine

Implantation of ureteral stents is associated with inconvenience for the patient, which is related to the natural ability of the ureter to contract. The most frequently used solution is the systemic administration of a diastolic drug, which has a relaxing effect on smooth muscle cells and decreases inconvenience. Current interdisciplinary research aimed at reducing the complications after the implantation of ureteral stents used in the treatment of upper urinary tracts with regard to infection, initiation of encrustation, and fragmentation of stents, and patient pain has not been resolved. This study presents the results of research regarding the impact of a biodegradable coating with the active substance on the physical and chemical properties of ureteral stents used in the treatment of the upper urinary tract. The surface of polyurethane double-J stents was coated with poly(lactide-glycolide) (PLGA) 85/15 loaded with papaverine hydrochloride (PAP) with diastolic properties. The coating for ureteral stents has been designed for short-term implantation. The effect of the coating on the process of encrustation and PAP release by the dynamic in vitro model with artificial urine (AU) up to 30 days was evaluated. The influence of AU on the physical and chemical properties of ureteral stents was determined. As part of the study, surface structure and topography researches; chemical composition analyses using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and wetting; and surface roughness studies of both PUR stents and coated stents were carried out. The proposed biodegradable PLGA+PAP coating is characterized by controlled drug release, while optimal physicochemical properties does not increase the encrustation process.

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

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

Assessment of the Grades of Vesicoureteral Reflux in Stented Ureters: An Experimental Study

INTRODUCTION

The aim of this experimental study is to assess, in a porcine model, the onset and grades of vesicoureteral reflux associated with ureteral stents.

METHODS

Twenty-four female porcine models were used. A 4.7-Fr ureteral stent was placed in all right ureters and kept in place for 6 weeks. Follow-ups were performed on weeks 1, 3, 6, and 12. Ultrasonography, cystoscopy, and fluoroscopy were used to analyze grade of hydronephrosis, presence and grade of vesicoureteral reflux, bacteriuria, and macroscopic changes of the ureteral orifices. Vesicoureteral reflux was classified using a modification of the International Reflux Study Committee grades.

RESULTS

91.7% animals present vesicoureteral reflux, 89.5% grade IA, 3.5% grade IB, and 7% grade II. There is a significant increase in reflux during follow-ups at 3 and 6 weeks, whereas 6 weeks after removal, 26.3% of the ureters still present vesicoureteral reflux. Hydronephrosis and macroscopic changes of the ureteral orifice increase significantly with stenting, but there is no significant association between them and vesicoureteral reflux; the relationship between bacteriuria and the presence of vesicoureteral reflux is not significant either.

CONCLUSION

Vesicoureteral reflux caused by ureteral stents in an animal model is mostly low grade and mainly affects the distal ureter.

Iatrogenic Ureteral Injury Treatment with Biodegradable Antireflux Heparin-Coated Ureteral Stent-Animal Model Comparative Study

Objective: The aim is to assess the effectiveness of a biodegradable antireflux ureteral stent with heparin coating in a comparative study (BraidStent^®-H) in an animal model for the treatment of iatrogenic ureteral perforation. Materials and Methods: A total of 24 female pigs underwent initial endoscopic, nephrosonographic, and contrast fluoroscopy assessment of the urinary tract. Afterward, unilateral iatrogenic perforation in proximal ureter model was performed. Then the animals were randomly assigned to Group-I, in which a double-pigtail stent was placed for 6 weeks, or Group-II, in which a BraidStent-H a biodegradable heparin-coated stent was placed. Follow-up assessments were performed at 1 and 6 weeks and 5 months. Results: In terms of therapeutic effectiveness, complete resolution was observed in 95.8% of Group-I animals and 87.5% in Group-II. No animals in Group-II showed vesicoureteral reflux (VUR) during the study; statistical significance was observed at 1 and 6 weeks versus Group-I. All stents in Group-II degraded without producing obstructive fragments and allowed distal ureteral peristalsis. Heparin coating was not efficient to reduce asymptomatic bacteriuria between groups. Pathologic assessment did not show any significance in the global score, but did in the "fibrosis in muscular layer" parameter, at the ureteral perforation healing area; Group-II showed higher healing quality. Conclusions: The biodegradable intraureteral BraidStent^®-H is highly effective for the minimally invasive treatment of ureteral perforation, since it displays controlled and predictable degradation, avoiding the development of VUR as well as irritation of the bladder trigone. Unfortunately, heparin coating was not effective in avoiding stent-associated bacteriuria.

A ten-year, single institution experience with percutaneous nephrostomy during pregnancy

PURPOSE

To evaluate the safety and efficacy of percutaneous nephrostomy (PCN) in pregnancy.

MATERIALS AND METHODS

PCN tubes were placed during 52 pregnancies in 49 patients from 2008 to 2018. The medical records during pregnancies were retrospectively reviewed for imaging findings, procedural parameters, outcomes of delivery, and complications.

RESULTS

The mean gestational age on percutaneous nephrostomy placement was 27 weeks (range, 8-36 weeks). PCN catheters were placed for the following indications: 1) flank or lower abdominal pain (42%), 2) obstructing calculi (37%), 3) pyelonephritis (20%), and 4) obstructing endometrioma (2%). Prior to PCN, retrograde ureteric stenting was performed in 17 of 49 patients (34%) and attempted but failed in 4 patients (8%). Nephrostomy drainage relieved pain completely or significantly in all 12 patients without prior ureteral stenting, but in only 4 of 10 with retrograde ureteric stents. In one patient in whom the ureteral stent had been removed, PCN relieved her flank pain. The mean number of PCN catheter exchanges was 1.6, ranging from 0 to 9, with a mean time interval of 21.3 days between exchanges. There were 29 difficult exchanges due to encrustation in 15 patients with a mean of 20.5 days between exchanges.

CONCLUSIONS

PCN drainage is a safe and effective treatment for managing symptomatic hydronephrosis in pregnant patients but is less effective in treating pain when retrograde ureteral stents are in place. Rapid encrustation, seen more commonly in pregnancy, tends to recur in the same patients and requires more frequent exchanges than the general population.

Management of stent-related symptoms with the use of α-blockers: A meta-analysis

Objectives: To assess the effectiveness of α-blockers at reducing stent-related morbidity compared to placebo using the Ureteric Symptom Score questionnaire (USSQ) at particular time points as originally set by the developers of the USSQ. Materials and methods: We conducted the study following the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) guidelines. Eligible articles were identified by a search of the Medical Literature Analysis and Retrieval System Online (MEDLINE) database for the period from 1 January 2006 to 30 November 2018. The search strategy included specific keywords and only articles in English were considered eligible. A meta-analysis of randomised controlled trials was done according to methodological quality, placebo-control use, and USSQ completion at the time points of 1 and 4 weeks after insertion, and 4 weeks after stent removal. The mean differences with 95% confidence intervals were calculated for outcomes, with a P < 0.05 considered statistically significant. Results: In all, eight papers were included for analysis. At 1 week after stent insertion, α-blockers were associated with a significant decrease in the USSQ Urinary Index score (UIS), Pain Index score, General Health Index score (GHIS), Sex Index score, and Work Index score (WIS). At 4 weeks after stent insertion, α-blockers were associated with a significant decrease in the UIS, GHIS and WIS only, whilst at 4 weeks after stent removal, α-blockers were associated with a significant decrease in the UIS and GHIS. Conclusions: The oral administration of α-blockers or their combinations have been shown to relieve stent morbidity, especially during the early period of stenting. The use of selective agents can therefore be considered; however, there is still the need for uniformly designed multi-centre randomised studies. Abbreviations: MD: mean difference; QoL: quality of life; RCT: randomised controlled trial; SRS: stent-related symptoms; USSQ: Ureteric Symptom Score questionnaire.

Freeze-casting porous chitosan ureteral stents for improved drainage

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

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.

Evaluation of pain perception associated with use of the magnetic-end ureteric double-J stent for short-term ureteric stenting

PURPOSE

To investigate the morbidity, complication rate, and pain perception during removal of a novel ureteric stent with a magnetic end using a-traumatic retrieval catheter.

METHODS

Between November 2013 and July 2015, 151 consecutive patients who underwent semirigid ureterorenoscopy (URS) for stone removal were prospectively enrolled. Stent removal was performed under local anesthesia using a special magnetic-end stent remover 1 week following URS. At follow-up, we obtained patients' medical history, urine culture result, renal ultrasonogram, and visual analog scale (VAS) score regarding stent irritation (VAS 1) and pain during removal (VAS 2).

RESULTS

Pain perception during stent removal was significantly less painful in patients with a magnet stent than in those with a regular stent (p < 0.001). Stent irritation was slightly higher in patients with an indwelling magnet stent than in those with a regular stent (p < 0.001). No significant differences in stent irritations were found in patients who had a magnetic stent for 4 weeks after laparoscopic pyeloplasty (p = 0.20). Patients with a magnetic stent experienced significantly less pain during removal with a median VAS 2 score of 2.5 and a mean VAS 2 score of 2.58 [standard deviation (SD) ± 0.90] than those without a magnetic stent a median VAS 2 of 6 and a mean VAS 2 of 5.88 (SD ± 1.43). The stent length correlated with stent irritation (p = 0.05), and it significantly correlated with pain during removal (p < 0.001).

CONCLUSION

The magnetic-end ureteric double-J stent is a safe option associated with less pain, particularly for male patients requiring short-term ureteric stenting.

Intraoperative Radiographic Determination of Ureteral Length as a Method of Determining Ideal Stent Length

INTRODUCTION

Accurate determination of ureteral length (UL) and appropriate stent length remains a challenge. The objective of this study was to describe an intraoperative technique to measure UL and determine appropriate stent length, and to compare this technique with other methods of determining appropriate stent length.

METHODS

Patients undergoing ureteroscopy requiring postoperative stenting and who had a preoperative CT were prospectively identified. Gender, age, height, body mass index, L1 to L5 lumbar height on CT, and surgeon's estimate of UL were recorded. UL was measured using four methods: direct measurement with a ureteral catheter, ureteropelvic junction (UPJ) to ureterovesical junction distance on axial and coronal CT, and using a novel intraoperative radiographic technique. Radiographic measurement was performed using a radiographic nipple marker affixed to the skin over the ureteral orifice (UO) and an angiographic catheter with radiopaque markings at 1 cm intervals. UL was the distance from the UPJ to the marker at the UO measured using the catheter markers. Correlation between direct measurement and the recorded variables and methods of ureteral measurement were calculated. Stent length was chosen based on radiographic measurement. Stents were deemed of appropriate length if they showed a proximal coil in the renal pelvis and a distal coil in the bladder without crossing midline.

RESULTS

Twenty-five ureters from 23 patients were included. Radiographically measured UL was strongly correlated with direct measurement. (r = 0.873, p < 0.01). Coronal and axial CT ULs were significantly associated with direct measurement (p < 0.05). Height, lumbar height, and surgeon's estimate of UL were not. Stents were deemed of appropriate length in 23/25 cases (92%).

CONCLUSIONS

This new method for radiographic UL measurement is strongly correlated with directly measured UL. A length of stent chosen based on radiographic UL resulted in an appropriate stent length.