Complications of ureteral stent placement

Natural biopolymers in the fabrication and coating of ureteral stent: An overview

Ureteral stents are indwelling medical devices that are most commonly used in treating different urinary tract complications like ureteral obstruction, kidney stones, and strictures, and allow normal urine flow from the kidney to the bladder. Tremendous work has been done in ureteral stent technology to meet the clinical demands, however, till-date a gold standard material for ureteral stents has not yet been developed. Many materials such as metal, and synthetic polymers have been published, however, the role of natural biopolymers has not yet been summarized and discussed. There is no detailed review published to explain the role of natural biopolymers in ureteral stent technology. This is the first review that explains and summarizes the role of natural polymer in ureter stent technology. In this review alginate and chitosan polymers are discussed in detail in the fabrications and coating of ureteral stents. It was summarized that alginate polymer alone or in combination with other polymers have been successfully used by many researchers for the manufacturing of ureteral stents with satisfactory results in vitro, in vivo, and clinical trials. However, alginate is rarely used to coat the surface of ureteral stent. On the other hand, only two reports are available on chitosan polymers for the manufacturing of ureteral stents, however, chitosan is largely used to coat the existing ureteral stents owing to their good antibacterial characteristics. Coating procedures can inhibit encrustation and biofilm formation. Nevertheless, the lack of antibacterial efficiency and inadequate coating limit their applications, however, natural biopolymers like chitosan showed significant promises in coating. Overall, the renewable nature, abundant, biocompatible, and biodegradable potential of natural polymer can be established with significant aspects as the ideal ureteral stent. To fully utilize the potential of the natural biopolymers in the ureteral stent design or coatings, an in-depth study is required to understand and identify their performance both in vitro and in vivo in the urinary tract.

Comparison of percutaneous antegrade double-J ureteral stent placement: first-hand vs. nephrostomy route approaches

OBJECTIVE

This study aimed to conduct a comparative analysis of procedural efficacy, safety, and patient outcomes between 2 distinct approaches for percutaneous antegrade double-J ureteral stent (DJS) insertion: the first-hand approach and via a nephrostomy route.

METHODS

Electronic records of patients undergoing percutaneous antegrade ureteral DJS placement from January 2016 to 2023 were reviewed. Patients were categorized into 2 groups based on stent placement technique: the first-hand group, involving a single-stage approach without prior percutaneous nephrostomy catheter insertion, and the nephrostomy group, where stent placement occurred through a percutaneous nephrostomy tube. Clinical data, including patient demographics, primary diagnoses, procedural details, complication rates, stent placement success, and post-procedural outcomes, were collected and analysed.

RESULTS

Both approaches demonstrated high technical success rates (93.1%). However, the nephrostomy route group exhibited a comparatively higher fluoroscopy exposure rate (8.2 min) than the first-hand group (6.8 min). Moreover, the complication risk increased by 3.08 times in patients treated with the nephrostomy method (P = .047). Notably, in cases of urinary malignancies, the preference was for placing DJS via nephrostomy.

CONCLUSION

The first-hand approach should be prioritized as the initial choice in suitable cases owing to its reduced fluoroscopy time, lower complication rate, and the single-stage nature of the procedure.

ADVANCES IN KNOWLEDGE

With the exception of cases necessitating urgent drainage, such as post-renal acute renal failure and urosepsis, the first-hand method is the primary approach for inserting DJS. This is primarily due to the significantly shorter radiation time and the single-stage nature of the procedure.

A method for detecting ureteral stent encrustations in medical CT images based on Mask-RCNN and 3D morphological analysis

Objective

To develop and validate a method for detecting ureteral stent encrustations in medical CT images based on Mask-RCNN and 3D morphological analysis.

Method

All 222 cases of ureteral stent data were obtained from the Fifth Affiliated Hospital of Sun Yat-sen University. Firstly, a neural network was used to detect the region of the ureteral stent, and the results of the coarse detection were completed and connected domain filtered based on the continuity of the ureteral stent in 3D space to obtain a 3D segmentation result. Secondly, the segmentation results were analyzed and detected based on the 3D morphology, and the centerline was obtained through thinning the 3D image, fitting and deriving the ureteral stent, and obtaining radial sections. Finally, the abnormal areas of the radial section were detected through polar coordinate transformation to detect the encrustation area of the ureteral stent.

Results

For the detection of ureteral stent encrustations in the ureter, the algorithm's confusion matrix achieved an accuracy of 79.6% in the validation of residual stones/ureteral stent encrustations at 186 locations. Ultimately, the algorithm was validated in 222 cases, achieving a ureteral stent segmentation accuracy of 94.4% and a positive and negative judgment accuracy of 87.3%. The average detection time per case was 12 s.

Conclusion

The proposed medical CT image ureteral stent wall stone detection method based on Mask-RCNN and 3D morphological analysis can effectively assist clinical doctors in diagnosing ureteral stent encrustations.

Migration of double-J ureteral stent in patients with ureteroileal anastomosis stricture undergoing radical cystectomy and orthotopic neobladder: Analysis risk factors of stent migration

The objective was to evaluate the incidence and degree of double-J ureteral stent (DJUS) migration. Additionally, we aimed to investigate the risk factors associated with stent migration in the orthotopic neobladder group. In this retrospective study, 61 consecutive patients were included; 35 patients (45 DJUS placements) underwent radical cystectomy with orthotopic neobladder and 26 patients (35 DJUS placements) underwent urinary bladder without cystectomy between July 2021 and March 2023. All the patients were treated with a DJUS for ureteric strictures. The technical success rate was 100% in each group. The DJUS migration was significantly higher in the orthotopic neobladder group, with 22 of 45 cases (48.9%), compared to the urinary bladder group, which had 4 of 35 cases (11.4%) (P ≤ .001). Among the patients in the orthotopic neobladder group who experienced DJUS migration, stent dysfunction occurred in 18 cases (81.8%), which was statistically significant (P = .003). Multivariate logistic regression analysis revealed that only the size of the DJUS was significantly and positively associated with migration (odds ratio:10.214, P = .010). DJUS migration can easily occur in patients undergoing radical cystectomy and orthotopic neobladder, and smaller stent sizes are associated with a higher incidence of migration.

Complications Subsequent to Urinary Tract Stent Placement: An Overview Focusing on the Imaging of Cancer Patients

Ureteral involvement by a tumor is common, and both partial and complete obstructions can result in symptoms that are distressing and debilitating, especially in cancer patients for whom the resection of the primary tumor is not considered an option. Maintaining ureteric patency in these patients is a challenge. In addition, in cases where a patient has undergone nephroureterectomy due to primary transitional cell cancer, it becomes necessary to decompress the urinary tract to preserve the contralateral kidney from irreversible damage. This is possibly due to ureteral stenting, both retrograde and anterograde, and percutaneous nephrostomy (PCN). Since imaging plays an important role in the routine monitoring of stents, their more and more increasing use requires radiologists to be familiar with these devices, their correct position, their potential complications, and their consequences. The aim of this review is to offer a comprehensive review of the imaging features of some urinary stents and to show the complications encountered in cancer patients as a direct consequence of an invasive diagnostic or therapeutic procedure. Specifically, we focus on ureteral stents and PCN.

Efficacy and Safety of Extracorporeal Shock Wave Lithotripsy (ESWL) in Patients With Infected Ureterohydronephrosis Due to Ureteral Stones Following Double-J Catheter Insertion

INTRODUCTION

Double-J ureteral catheters in patients with ureteral lithiasis undergoing extracorporeal shockwave lithotripsy (ESWL) procedures reduce the efficacy of the procedure or have no effect on the stone-free rate. However, the effect of double-J catheters on the patients in whom they were inserted for infected hydronephrosis is not known. The aim of our study was to evaluate the efficacy and safety of the ESWL procedure in patients with ureteral lithiasis and double-J catheters previously inserted for infected hydronephrosis.

METHOD

We conducted a comparative case-control, match-paired study in a group of patients with ureteral lithiasis treated by ESWL from January 1, 2018, to March 1, 2023, who were divided into two groups according to the presence of the double-J catheter. For each patient with the double-J catheter from the study group, we selected one patient for the control group without the double-J catheter and matched them in terms of size, location of stones, and body mass index (BMI). We analyzed the stone-free rate and complications that occurred in the two groups.

RESULTS

Forty patients with ureteral lithiasis and a double-J catheter inserted for infected hydronephrosis were enrolled in the study group. The control group included 40 patients with ureteral stones without double-J catheters. The patients in the two groups were predominantly men with stones located in the lumbar region and on the right side and with a BMI between 25 and 30 kg/m2. The stones had an average size of 0.9+/-0.12mm and 0.89+/-0.15mm, respectively (p=0.624). There was no statistically significant difference in stone-free rate between the two groups after the first session of ESWL (47.5% vs. 52.5%, p=0.502), the second (70% vs. 75%, p = 0.616), and the third session (85% vs. 87.5%, p=0.761). The rate of complications was similar in both groups (7.5% vs. 5%, p=0.761).

CONCLUSIONS

The presence of double-J catheters inserted in patients with ureteral stones who underwent ESWL for infected hydronephrosis does not affect the stone-free rate of the procedure or the complication rate. The procedure of ESWL in patients with ureteral lithiasis and double-J catheters inserted for infected hydronephrosis is a safe and efficient method that can be recommended as an initial treatment alongside retrograde ureteroscopy.

Placenta accreta spectrum into the parametrium, morbidity differences between upper and lower location

OBJECTIVE

To demonstrate the surgical and morbidity differences between upper and lower parametrial placenta invasion (PPI).

MATERIALS AND METHODS

Forty patients with placenta accreta spectrum (PAS) into the parametrium underwent surgery between 2015 and 2020. Based on the peritoneal reflection, the study compared two types of parametrial placental invasion (PPI), upper or lower. Surgical approach to PAS follows a conservative-resective method. Before delivery, surgical staging by pelvic fascia dissection established a final diagnosis of placental invasion. In upper PPI cases, the team attempted to repair the uterus after resecting all invaded tissues or performing a hysterectomy. In cases of lower PPI, experts performed a hysterectomy in all cases. The team only used proximal vascular (aortic occlusion) control in cases of lower PPI. Surgical dissection for lower PPI started finding the ureter in the pararectal space, ligating all the tissues (placenta and newly formed vessels) to create a tunnel to release the ureter from the placenta and placenta suppletory vessels. Overall, at least three pieces of the invaded area were sent for histological analysis.

RESULTS

Forty patients with PPI were included, 13 in the upper parametrium and 27 in the lower parametrium. MRI indicated PPI in 33/40 patients; in three, the diagnosis was presumed by ultrasound or medical background. The intrasurgical staging categorizes 13 cases of PPI performed and finds diagnosis in seven undetected cases. The expertise team completed a total hysterectomy in 2/13 upper PPI cases and all lower PPI cases (27/27). Hysterectomies in the upper PPI group were performed by extensive damage of the lateral uterine wall or with a tube compromise. Ureteral injury ensued in six cases, corresponding to cases without catheterization or incomplete ureteral identification. All aortic vascular proximal control (aortic balloon, internal aortic compression, or aortic loop) was efficient for controlling bleeding; in contrast, ligature of the internal iliac artery resulted in a useless procedure, resulting in uncontrollable bleeding and maternal death (2/27). All patients had antecedents of placental removal, abortion, curettage after a cesarean section, or repeated D&C.

CONCLUSIONS

Lower PAS parametrial involvement is uncommon but associated with elevated maternal morbidity. Upper and lower PPI has different surgical risks and technical approaches; consequently, an accurate diagnosis is needed. The clinical background of manual placental removal, abortion, and curettage after a cesarean or repeated D&C could be ideally studied to diagnose a possible PPI. For patients with high-risk antecedents or unsure ultrasound, a T2 weight MRI is always recommended. Performing comprehensive surgical staging in PAS allows the efficient diagnosis of PPI before using some procedures.

Analysis of Bacterial Stent Colonization: The Role of Urine and Device Microbiological Cultures

In this study, we explored the incidence of double J (JJ) contamination of patients who underwent an endourological procedure for urinary stones and ureteral stenosis. We developed a prospective study between January 2019 and December 2021. Ninety-seven patients, 54 male and 43 female, were enrolled. Urine culture was taken during four steps: before stent insertion, a sample from selective renal pelvis catheterization, a sample two days after the JJ insertion and finally, after the stent removal procedure. At the time of the stent removal, 1 cm of proximal and distal ends were cut off and placed in the culture for bacterial evaluation. Cohen's kappa coefficient value (k) and concordance rates of microbiological culture results were evaluated. The study group comprised 56% of male patients. Proximal and distal stent cultures were positive in 81 and 78 patients. The concordance rate of microbiological cultures between proximal and distal double J stent is 88% (k 0.6). The most common pathogens isolated from urine and stent cultures were Enterococcus spp. in 52 cases and Klebsiella spp. in 27 cases.

Identifying ureteral stent encrustation using machine learning based on CT radiomics features: a bicentric study

Obstructive

To develop and validate radiomics and machine learning models for identifying encrusted stents and compare their recognition performance with multiple metrics.

Methods

A total of 354 patients with ureteral stent placement were enrolled from two medical institutions and divided into the training cohort (n = 189), internal validation cohort (n = 81) and external validation cohort (n = 84). Based on features selected by Wilcoxon test, Spearman Correlation Analysis and least absolute shrinkage and selection operator (LASSO) regression algorithm, six machine learning models based on radiomics features were established with six classifiers (LR, DT, SVM, RF, XGBoost, KNN). After comparison with those models, the most robust model was selected. Considering its feature importance as radscore, the combined model and a nomogram were constructed by incorporating indwelling time. Accuracy, sensitivity, specificity, area under the curve (AUC), decision curve analysis (DCA) and calibration curve were used to evaluate the recognition performance of models.

Results

1,409 radiomics features were extracted from 641 volumes of interest (VOIs) and 20 significant radiomics features were selected. Considering the superior performance (AUC 0.810, 95%CI, 0.722-0.888) in the external validation cohort, feature importance of XGBoost was used as a radscore, constructing a combined model and a nomogram with indwelling time. The accuracy, sensitivity, specificity and AUC of the combined model were 98, 100, 97.3% and 0.999 for the training cohort, 83.3, 80, 84.5% and 0.867 for the internal cohort and 78.2, 76.3, 78.8% and 0.820 for the external cohort, respectively. DCA indicates the favorable clinical utility of models.

Conclusion

Machine learning model based on radiomics features enables to identify ureteral stent encrustation with high accuracy.

Upper tract heparin instillation for maintenance of ureteral stent patency

PURPOSE

The study aimed to evaluate the efficacy of heparin packing after antegrade ureteral stent placement in the renal pelvis to protect against early dysfunction.

METHOD

From December 2019 to September 2021, 44 double J (DJ) stent placements were performed with heparin packing (heparin packing group). Between February 2008 and March 2014, 250 DJ stent placements without heparin packing were performed (control group). One-week patency and 3-month patency of the two groups were compared. The patency of the DJ stent according to the blood retention grade in the urinary system was also compared by subgroup analysis.

RESULT

The 1-week patency rate in the heparin packing group was significantly higher compared to the control group (88.6% and 65.2%, respectively, p = 0.002). There was no significant difference in the 3-month patency rate between the two groups (72.7% and 60.9%, respectively; p = 0.187). In the subgroup analysis, among the patients with high blood retention grades, the 1-week patency rates of the heparin packing group were significantly higher than that of the control group (100% and 60.9%, respectively; p < 0.001).

CONCLUSION

Heparin packing through the catheter after DJ stent installation aids in DJ stent patency.

Inner surface modification of polyurethane ureteral stents using plasma-enhanced chemical vapor deposition to improve the resistance to encrustation in a pig model

PURPOSE

We developed a ureteral stent with a non-fouling inner surface using plasma micro-surface modification technology. This study aimed to evaluate the safety and efficacy of this stent in animal model.

MATERIALS AND METHODS

Ureteral stents were placed in five Yorkshire pigs. A bare stent was inserted on one side and an inner surface-modified stent was inserted on the other side. Two weeks after stenting, laparotomy was performed to harvest the ureteral stents. The changes in the inner surface were grossly evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In addition, if encrustation was observed, the components were analyzed using Fourier transform infrared spectroscopy. Urine cultures were used for safety assessment.

RESULTS

In all models, urine cultures did not show any bacterial growth before and after stenting, and stent-related complications were not identified. Hard materials were palpable in four bare models. Palpable material was not identified in the modified stent. Calcium oxalate dihydrate/uric acid stones were identified in two bare stents. In the SEM images with EDS, biofilm formation was confirmed in the bare stents. Biofilm formation was significantly less on the inner surface of the modified stent, and the intact surface of the modified stent was larger than that of the bare stent.

CONCLUSIONS

The application of a specialized, plasma-enhanced, chemical vapor deposition technology to the inner surface of ureteral stents was safe and showed resistance to biofilm formation and encrustation.

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.

A case report on the management of neglected and forgotten DJ stent for 15 years with severe encrustation and multiple renal and bladder stones

INTRODUCTION AND IMPORTANCE

The placement of ureteral DJ stents is currently regarded as a common and indispensable urologic tool (Dyer et al., 2002 [1]). However, using them can lead to complications. Infection, stent migration, encrustation, stone formation, and stent fragmentation are some of these complications (Mahmood et al., 2018 [2]). Stent-related complications are inversely associated with time (Lombardo et al., 2022 [3]). In this case report, we present multimodal therapy, which also includes open surgery and endourologic procedures for the removal of severely encrusted DJ stents.

CASE PRESENTATION

A 22-year-old male who underwent nonspecific flank surgery 15 years ago, had a stent placed, and was lost to follow-up. He had severe stent encrustation at the presentation. He also had a solitary bladder stone and many pelvic stones discovered. Initially, cytolithotrity and semirigid ureteroscopy with laser lithotripsy were performed, and the encrusted stent was removed. Subsequently, an open cytolitotomy was done. Followed by an ultrasound-guided PCNL at which time the remaining stones were removed. The patient was followed for eighteen months and has been in better condition.

DISCUSSION

The key risk factor for the development of encrustation has been shown repeatedly to be the duration of stent indwelling time (Lombardo et al., 2022 [3]). In the absence of clear guidelines for the removal of retained stents, this problem has been approached with a variety of treatment modalities (Bidnur et al., 2016 [4]). A stepwise approach with combined endo-urology and open surgery can be used for the management.

CONCLUSION

Forgotten and neglected DJ stentsfor a long time can cause multiple complications. The best treatment is the prevention of this complication with a stent registry and increase awareness among the patients and their attendants.

Effect of phytate on crystallization on ureteral stents and bacterial attachment: an in vitro study

The use of double J ureteral stents can lead to several adverse effects, as urinary infection. Bacteria tend to colonize the stent surface, leading to the formation of bacterial biofilms. The presence of urease-producing bacteria increase the urine pH leading to the incrustation and blockage of the stent. On the other hand, these large crystalline masses function as niduses, allowing the attachment of even more bacteria and decreasing its exposure to antibiotics. The aim of this in vitro study was to assess the effect of phytate on the attachment of bacteria to the catheter surface under conditions that favor crystallization. Catheter sections were incubated in a synthetic urine medium (pH 6.5) in the presence or absence of Pseudomonas aeruginosa and phytate. Amount of calcium deposits was measured using an Arsenazo III colorimetric method and the number of attached bacteria to the stent was determined. Differences were assessed using an ANOVA with a Bonferroni post hoc test. The formation of calcium phosphate deposits (brushite and hydroxyapatite) and oxalate crystals (COM), as were as the amount of bacteria decreased when phytate was present. Thus, phytate successfully decreased bacterial adhesion by inhibiting the formation of crystalline deposits.

Application, Advancement, and Complication of Ureteral Stent and Encrustation: A Major Complication

Three technological aspects have a significant impact on the functioning of an optimal stent. The substance it is made up of, model or design, and coating of the surface are important areas for research. To give recognition of an ideal stent, it summarizes some essential breakthroughs that occurred. Encrustation is a regular problem that can happen when a ureteral stent is implanted in the urinary tract, and it may be dangerous. The part of the paper covers the mechanism of encrustation, stent management, and the most recent technologies created to solve this problem. Encrustation has a complicated and diverse mechanism that includes the time it stays inside, patient-specific risk factors, controlled film production, formation of biofilm, and deposition of minerals. A number of high-tech advancements in stent substances and coverings/coatings could help to reduce the danger of encrustation of stents. It's critical to determine the amount of encrustation of a stent so that therapy options can be tailored properly. For the care of ureteral stents, which are encrusted, we offer a unique therapeutic protocol. The duration of stent indwelling time has been repeatedly established to be a critical risk factor for the evolution of encrustation. The period of stent indwelling time has consistently been established to be a critical risk element for the evolution of encrustation. Patients who are predisposed to bacteriuria and urinary lithiasis are also predisposed to encrustation. Repeated urinary tract infections, diabetes, and chronic kidney failure are among the factors that might escalate urine bacterial load, which can lead to stent encrustation. Due to the prevalence of ureteral stents in urology, it's critical to keep up to date on the best ways to prevent stent encrustation, recognize high-risk patients, and remove them using multimodal techniques.

Jejunal perforation and upward migration of double J stents during the cystoscopic procedure: a case report and review of literature

While double J (DJ) stenting is common worldwide in the urological procedure, it may associate with severe and catastrophic complications. Penetration of the jejunum and upward migration of double J (DJ) stents during cystoscopic DJ stent procedure are rare complications with few reported cases in the literature. We present a 65-year-old male presented with acute renal failure and peritonitis one week after failed cystoscopic removal of DJ stents. Radiographic investigations showed upward migration of the right DJ stent and a total displacement of the left DJ stent to the peritoneal cavity with peritonitis, bladder perforation, and jejunal injuries. The right DJ stent was removed via the ureteroscopic procedure. Then, open abdominal surgery was performed to remove the left DJ stent and repair the injured bladder wall and jejunal segment. In conclusion, synchronous upward DJ stent migration and peritoneal DJ stent malposition with jejunal and bladder injuries are rare and severe complications of the cystoscopic DJ stent procedure. The treatment should be performed depending on the time of diagnosis, nature of the injury, and general clinical conditions of the patient.

Factors Associated with Ureteral Stent Failure in Patients with Malignant Ureteral Obstruction

Introduction: Management of malignant ureteral obstruction (MUO) with ureteral stents remains a clinical challenge, often involving frequent stent exchanges attributable to stent failure or other urological complications. We report our institutional experience with ureteral stents for management of MUO, including analysis of clinical factors associated with stent failure. Methods: We performed a retrospective review of patients treated with indwelling ureteral stents for MUO in nonurothelial malignancies at our tertiary-care institution between 2008 and 2019. Univariate Cox proportional hazards analysis was performed to identify clinical variables associated with stent failure and stent-related complications. Stent failure was defined as need for unplanned stent exchange, placement of percutaneous nephrostomy (PCN), or tandem stents. Results: In our cohort of 78 patients, the median (range) number of stent exchanges was 2 (0-17) during a total stent dwell time of 4.3 (0.1-40.3) months. Thirty-four patients (43.6%) developed a culture-proven urinary tract infection (UTI) during stent dwell time. Thirty-five patients (44.8%) had stent failure. Twenty-two patients (28.2%) underwent unplanned stent exchanges, 23 (29.5%) required PCN after initial stent placement, and 6 (7.7%) required tandem stents. Ten (28.6%) patients with stent failure were treated with upsized stents, which led to resolution in seven patients. Stent failure occurred with 20/44 (45.4%) Percuflex™, 15/27 (55.6%) polyurethane, and 2/3 (66.7%) metal stents. In patients with ≥2 exchanges (N = 45), median time between exchanges was 4.1 (2.0-14.8) months. Bilateral stenting and history of radiation predicted UTI development. Median overall patient survival after initial stent placement was 19.9 months (95% CI 16.5-37.9 months). Conclusions: Ureteral stent failure poses a significant medical burden to patients with MUO. Better methods to minimize stent-related issues and improve patient quality of life are needed. Using a shared decision-making approach, clinicians and patients should consider PCN or tandem stents early in the management of MUO.

Inner surface modification of ureteral stent polyurethane tubes based by plasma-enhanced chemical vapor deposition to reduce encrustation and biofilm formation

Encrustation and/or biofilm formation in ureteral stents are major causes of obstruction and reduce the lifetime of a ureteral stent. In this study, the inner surfaces of polyurethane (PU) tubes (inner and outer diameters of 1.2 and 2.0 mm, respectively) were reformed with Ar, O₂, and C₂H₂ gases using specialized plasma-enhanced chemical vapor deposition techniques for the first time. Then, the modified PU tubes were immersed in urine for 15 days, and the characteristics of the inner surfaces were analyzed. Depending on the modification procedure, the corresponding inner surface exhibited different chemical properties and different rates of encrustation and biofilm formation. For a hydrophilic surface treated with Ar and O₂, encrustation and biofilm formation increased, while for the C₂H₂ coating, the development of encrustation and biofilm reduced by more than five times compared with the untreated bare PU tube. This study demonstrated that inner plasma surface modification of ureteral stents greatly enhances resistance to encrustation and biofilm formation.

A novel telescopic access sheath method to manage encrusted or knotted retained stents

Purpose:

Encrusted and knotted stents may cause serious urologic complications. This study aimed to develop a novel and minimally invasive technique to manage encrusted or knotted retained ureteral stents.

Materials and Methods:

This technique was used in nine patients with retained stents. Through rigid cystoscopy, the stents were pulled out of the urinary meatus. The access sheath was modified by cutting the distal end of its obturator. The modified access sheath was advanced over the retained stents in a telescopic manner to remove the encrusted and/or knotted stents.

Results:

Six patients had encrustations, two had knot formation, and one had both encrustation and knot formation. The encrustations were peeled off in the process. The knots were either undone or pulled through the lumen of the access sheath. The retained stents were removed intact from all patients without any complications.

Conclusion:

The access sheath method described in this article provides a simple alternative for the removal of encrusted or knotted retained stents. However, this technique requires further validation to establish its safety and efficacy.

Evaluation of Selected Properties of Sodium Alginate-Based Hydrogel Material—Mechanical Strength, μDIC Analysis and Degradation

The search for ideal solutions for the treatment of urethral stenosis continues. This includes developing the material, design, while maintaining its optimal and desired properties. This paper presents the results of the research conducted on sodium alginate-based hydrogel material (AHM), which may be used as a material for stents dedicated to the treatment of pathologies occurring in the genitourinary system. In order to determine the selected parameters of the AHM samples, strength and degradation tests, as well as analysis of the micro changes occurring on the surface of the material using a digital image correlation (µDIC) system, were performed. This study shows that the material possessed good mechanical strength parameters, the knowledge of which is particularly important from the point of view of the stent-tissue interaction. The degradation analysis performed showed that the AHM samples degrade in an artificial urine environment, and that the degradation time mainly depends on the chemical composition of the material. The novel µDIC method performed allowed us to characterize the homogeneity of the material structure depending on the cross-linking agent used.

Peritoneal perforation and peritonitis after antegrade double-J stent insertion: A case report and review of the literature

Penetration of peritoneal cavity during antegrade double-J (DJ) stenting is rare. A 52-year-old woman presented with signs of peritonitis for 3 days after left PCNL. Abdominal CT scan revealed a perforation of the peritoneum by the distal coil of DJ stent, which was reinserted into the bladder by ureteroscopy.

Rare complication of ureteral double-J stenting after ureteroscopy: pelvic ectopic renal parenchymal perforation

Scarce data are available on pelvic ectopic renal parenchymal perforation. However, this complication might lead to serious consequences. Clinicians should pay attention to the early identification and treatment of this complication. We herein report the first case of pelvic ectopic renal parenchymal perforation caused by a double-J stent after ureteroscopy. Compared with previously reported cases of renal parenchymal perforation not involving an ectopic kidney, our case involved no renal capsule hematoma and no other serious complications. Our primary management strategy was to review relevant examinations and tests, perform close monitoring, and instruct the patient to stay in bed. The patient recovered smoothly after the ureteral stent was removed 1 month postoperatively.

Is primary ureteroscopy an alternative to emergency stenting in terms of quality and cost?

Introduction

The aim of this article was to investigate quality and cost benefits of managing urolithiasis by primary ureteroscopic procedures (P-URS) during index admission to hospital. With the rise in prevalence of urolithiasis, the focus has shifted to manage these patients during their first admission rather than using temporary measures like emergency stenting (ES) or nephrostomies which are followed by deferred ureteroscopic procedures (D-URS). We compared results of P-URS, D-URS and ES procedures in terms of quality and cost benefits.

Material and methods

Data was collected retrospectively for all P-URS, D-URS and ES procedures performed during year 2019. A total of 85 patients underwent ES while as 138 patients underwent elective URS (26 had P-URS and 112 had D-URS). The quality assessment was based in relation to patient factors including- number of procedures per patient, number of days spent at hospital, number of days off work. Cost analysis included theatre and hospital stay expenses, loss of working days.

Results

This study revealed that the average hospital stay of patients on index admission who had a ES was 1.35 days (Total 3.85) and who had P-URS was 1.78 days (Total 2.78). Overall, additional expenditure in patients who did not undergo primary URS was in the range of 1800-2000€ (excluding loss of work for patients, who needed to return for multiple procedures).

Conclusions

We conclude approach of P-URS and management of stones in index admission is very effective in both improving quality of patients as well as bringing down cost expenditure effectively.

Technical Notes on Fluoroscopy-Guided Removal of Metallic Ureteral Stents

This manuscript describes various techniques for fluoroscopy-guided removal of metallic ureteral stents. Fifteen patients underwent 17 fluoroscopy-guided removal procedures of 22 metallic ureteral stents. The simple or modified snare or retrieval hook technique was primarily used for antegrade access, whereas the loop snare technique was primarily used for retrograde access. Overall 64.7% of the stents were removed using the initial retrieval technique, and 82.4% were removed using an adjunct technique. Procedure-related complications included hematuria in 41.2% of cases and resolved spontaneously in all patients. Fluoroscopy-guided removal of metallic ureteral stents is safe and effective.

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.

Functional Properties of Polyurethane Ureteral Stents with PLGA and Papaverine Hydrochloride Coating

Despite the obvious benefits of using ureteral stents to drain the ureters, there is also a risk of complications from 80-90%. The presence of a foreign body in the human body causes disturbances in its proper functioning. It can lead to biofilm formation on the stent surface, which may favor the development of urinary tract infections or the formation of encrustation, as well as stent fragmentation, complicating its subsequent removal. In this work, the effect of the polymeric coating containing the active substance-papaverine hydrochloride on the functional properties of ureteral stents significant for clinical practice were assessed. Methods: The most commonly clinically used polyurethane ureteral Double-J stent was selected for the study. Using the dip-coating method, the surface of the stent was coated with a poly(D,L-lactide-glycolide) (PLGA) coating containing the papaverine hydrochloride (PAP). In particular, strength properties, retention strength of the stent ends, dynamic frictional force, and the fluoroscopic visibility of the stent during X-ray imaging were determined. Results: The analysis of the test results indicates the usefulness of a biodegradable polymer coating containing the active substance for the modification of the surface of polyurethane ureteral stents. The stents coated with PLGA+PAP coating compared to polyurethane stents are characterized by more favorable strength properties, the smaller value of the dynamic frictional force, without reducing the fluoroscopic visibility.

Intrathoracic ureteric stent migration through a reno-pleural fistula: a case report of rare antegrade ureteric stenting complication

BACKGROUND

Malignant obstruction and associated hydronephrosis is a common complication of advanced cervical cancer. Percutaneous nephrostomy (PCN) followed by antegrade stenting is often required to relieve obstruction as retrograde access fails in considerable proportion of such patients. Reno-pleural fistula is a rare complication of PCN which creates a patent connection between the renal collecting system and the thoracic cavity, and urine accumulation in the pleural space can cause pleural effusion (i.e., urinothorax). Upward or downward migration is a complication of indwelling ureteric stents. Further migration with extrusion outside of the urinary tract is uncommon. Herein we present an unprecedented case in adult of ureteric stent upward migration through a reno-pleural fistula into the thoracic cavity managed by thoracoscopy.

CASE PRESENTATION

A 66-year-old female was diagnosed of advanced stage cervical cancer with suspicious bladder invasion. Given her bilateral hydronephrosis with impaired renal function, she underwent bilateral PCN and subsequent antegrade ureteric stenting. However, she presented with dyspnea, right back pain, and oliguria four days after bilateral PCN catheter removal. Computed tomography reported massive right pleural effusion and an intrathoracic ureteric stent within reno-pleural fistula. Thoracoscopy with thoracostomy was performed to remove the ureteric stent and urine in right pleural space. A week later, urinothorax had resolved and right PCN was performed again. She was discharged after regaining normal renal function with right PCN and a left ureteric stent in place.

CONCLUSIONS

A reno-pleural fistula can serve as a route for ureteric stent migration and that continuous drainage of urine can cause urinothorax once the stent reaches the thoracic cavity. Anytime a supracostal approach is used for PCN, even when using small caliber catheters, clinicians should pay special attention given the risk of pleural injury and subsequent complications.

Potential strategies to prevent encrustations on urinary stents and catheters - thinking outside the box: a European network of multidisciplinary research to improve urinary stents (ENIUS) initiative

Introduction: Urinary stents have been around for the last 4 decades, urinary catheters even longer. They are associated with infections, encrustation, migration, and patient discomfort. Research efforts to improve them have shifted onto molecular and cellular levels. ENIUS brought together translational scientists to improve urinary implants and reduce morbidity.Methods & materials: A working group within the ENIUS network was tasked with assessing future research lines for the improvement of urinary implants.Topics were researched systematically using Embase and PubMed databases. Clinicaltrials.gov was consulted for ongoing trials.Areas covered: Relevant topics were coatings with antibodies, enzymes, biomimetics, bioactive nano-coats, antisense molecules, and engineered tissue. Further, pH sensors, biodegradable metals, bactericidal bacteriophages, nonpathogenic uropathogens, enhanced ureteric peristalsis, electrical charges, and ultrasound to prevent stent encrustations were addressed.Expert opinion: All research lines addressed in this paper seem viable and promising. Some of them have been around for decades but are yet to proceed to clinical application (i.e. tissue engineering). Others are very recent and, at least in urology, still only conceptual (i.e. antisense molecules). Perhaps the most important learning point resulting from this pan-European multidisciplinary effort is that collaboration between all stakeholders is not only fruitful but also truly essential.

Risk of chronic kidney disease in patients with retained ureteral stents

Objective:

Numerous publications describe the management of stent encrustations, but few address long-term risks. The purpose of this study is to analyze the incidence of new chronic kidney disease attributed to retained ureteral stents in a large multi-institutional patient population.

Materials and methods:

A retrospective chart review of stone disease patients with ureteral stent placement was done in the nation-wide Cerner Health Facts database between 10 July 2009 and 7 June 2018. The estimated glomerular filtration rate was calculated using serum creatinine and the Modification of Diet in Renal Disease Study equation. The study focused on patients with stent duration longer than 6 months and an estimated glomerular filtration rate above 60 ml/min/1.73 m2 before stent placement.

Results:

A total of 1234 stent placements were documented in the Cerner database, 108 patients had a normal estimated glomerular filtration rate prior to the retained stent. The median duration of retained stents was 12.1 months (range 6.1 to 77.7 months), and 33 (30.6%) patients developed new onset chronic kidney disease compared to 8.3% in patients with non-retained stents.

Conclusion:

A new onset of chronic kidney disease was observed in 30.6% of patients with retained ureteral stent, emphasizing the importance of patient counseling and preventive measures to ensure patient compliance and follow-up.

Level of evidence:

Not applicable in this multi-institutional cohort study.

Does potassium citrate administration change the type and composition of encrusted material on Double-J stent compared to primary stone?

Purpose

To evaluate the effect of potassium citrate administration on the composition of encrusted material on the ureteral stent after Double-J insertion.

Methods

We designed a randomized clinical trial for our study; 65 patients that underwent transurethral lithotripsy and Double-J stent insertion were included in the study after informed consent and divided into two groups. In the first group (33 patients) potassium citrate was prescribed after surgery till stent removal and the second group (32 patients) followed without prescribing this medication. After stent removal, encrusted materials on removed stents were analyzed then the type and composition of encrusted material compared with the primary stone that was removed.

Results

Our results revealed that the type and composition of primary stone and encrusted stone were similar in patients that do not receive potassium citrate (p-value of 0.073, 0.251 and 0.944 for calcium oxalate, uric acid, and calcium phosphate respectively). In patients that taking potassium citrate rate of calcium oxalate (p-value < 0.001) and uric acid (p-value < 0.001) material on encrusted stent significantly decreased compared with the non-intervention group.

Conclusion

Results of this study revealed that taking of potassium citrate after ureteral stent insertion significantly decreases the formation of calcium oxalate and uric acid encrusted material on Double-J stent so it could be recommended for prevention of stent encrustation in patients that primary stone analysis are calcium oxalate and uric acid stone.

Predictors of antegrade ureteral stenting failure: a single-center experience in patients with malignant and benign ureteral obstruction

OBJECTIVE

To determine the potential predictors of antegrade ureteral stenting (AUS) failure in patients with malignant and benign ureteral obstruction.

METHOD

We retrospectively evaluated 116 AUS procedures performed in 80 patients for ureteral obstruction due to malignant and benign causes. Variables such as etiology for obstruction, ureter shape, previous treatment regimen, history of ileal loop diversion, and presence of percutaneous nephrostomy were recorded. Univariate and multivariate logistic regression methods were used between these variables and stent failure.

RESULTS

Antegrade ureteral stenting was performed as single stage in 24 procedures (n: 24/116, 21%) and performed as a two-step approach after percutaneous nephrostomy in 92 procedures (n: 92/116, 79%). Ureteral stent was successfully deployed in 112 AUS procedures (n: 112/116, 96.5%). In 35 of these successful procedures, the patients were referred to our department due to prior failed retrograde ureteral stenting (RUS). Subsequent stent failure occurred in 40 procedures after a median interval of 39 days. Pre-stenting percutaneous nephrostomy (PN) was a statistically significant risk factor for stent failure (p: 0.041), and age showed an inverse relationship with stent failure (p: 0.008). Complications in early (within the first 30 days after procedure) and late stage occurred in a total of 17 procedures. Early complications included urinary tract infection (n: 11), stent migration (n: 3), and malposition (n: 1). Late complications (after 30 days) were urinary tract infection (n: 1) and stent migration (n: 1).

CONCLUSION

This study suggests that AUS can be performed effectively in both benign and malignant ureteral obstructions including cases with prior failed RUS. Two-step AUS after percutaneous nephrostomy was found to be a significant risk factor for subsequent stent failure in our study cohort.

A rare case of double J stent migration in the kidney

Double-J stents are among the basic and commonly used tools in urology. There are a lot of complications that can occur during DJ placement. We are presenting 62 years old woman, who was admitted in Urology Department with symptoms of left lumbar pain, irradiating towards inguinal area and hematuria. The computed tomography (CT) scan of abdomen and pelvis defined a propagated DJ stent in the left kidney. Lumenis Holmium laser VersaPulse 100 W was used for resection of the double J stent and after that it was removed from the kidney in pieces.

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.

Removal and repositioning of urinary tract implants by use of an endovascular snare system in dogs and cats (2013-2019)

OBJECTIVE

To report the fluoroscopic removal or repositioning of urinary tract implants in dogs and cats by use of an endovascular snare system (ESS) and to report procedural usefulness and complications in dogs and cats.

ANIMALS

3 cats and 14 dogs.

PROCEDURES

A medical records review was performed to identify dogs and cats that underwent removal or repositioning of urinary tract foreign bodies or implants by use of an ESS with fluoroscopic guidance at a veterinary teaching hospital from 2013 to 2019.

RESULTS

Dogs had a median weight of 25 kg (55 lb) with a range of 3.5 to 60.6 kg (7.7 to 133.3 lb), and cats had a median weight of 5 kg (11 lb) with a range of 4.2 to 5.4 kg (9.2 to 11.9 lb). By use of an ESS, 12 patients (2 cats and 10 dogs) underwent transurethral retrieval of retained vesicourethral implants or ureteral stents, 2 dogs underwent transurethral ureteral stent repositioning, 1 cat and 2 dogs underwent transnephric retrieval of ureteral stents, and 1 dog underwent cystoscopic-assisted transureteral ureteral stent retrieval. All procedures were successfully performed, and there were no associated procedural complications.

CONCLUSIONS AND CLINICAL RELEVANCE

Retained vesicourethral implants or ureteral stents were successfully retrieved by use of an ESS in dogs and cats transurethrally or with an open or percutaneous transnephric approach and fluoroscopic guidance. These techniques should be considered as an alternative or adjunct to more invasive methods for implant retrieval or manipulation.

Experimental Assessment of New Generation of Ureteral Stents: Biodegradable and Antireflux Properties

Objective: The aim was to assess a new biodegradable and antireflux intraureteral stent (BraidStent^®) design in a swine model after ureteral laparoscopic operation. Materials and Methods: A total of 24 female pigs underwent initial endoscopic, nephrosonographic, and contrast fluoroscopy assessment of the urinary tract. Afterward, unilateral ureteropelvic junction obstruction was performed by laparoscopic approach. Six weeks later, the animals underwent laparoscopic Anderson-Hynes pyeloplasty, and were randomly assigned to Group-I, in which a double-pigtail ureteral stent was inserted for 6 weeks, or Group-II, in which a BraidStent^®, a biodegradable intraureteral stent design, was placed. Follow-up assessments were performed at 3 and 6 weeks and 5 months. Results: In terms of therapeutic success, complete resolution was observed in 91.6% of Group-I animals and 88.8% in Group-II. No evidence of vesicoureteral reflux (VUR) was observed in Group-II animals and statistical significance in VUR and ureteral orifice damage were observed between groups. BraidStent^® degradation occurred in a controlled manner between 3 and 6 weeks, without obstructive fragments. Distal ureteral peristalsis was maintained in 66.6% and 83.3% in Group-II at 3 and 6 weeks of follow-up, respectively. In Group-II, the positive bacteriuria rate was 41.6% and the migration rate 25%. Pathological assessment showed a significant improvement in ureteral healing in Group-II vs Group-I. Conclusions: The results of this comparative study in a porcine model indicate that the intraureteral BraidStent performed similarly to conventional ureteral stents. It avoids complete ureteral length intubation, the adverse effects associated with conventional ureteral stents, and maintains a high level of distal ureteral peristalsis. Moreover, the BraidStent^® exhibited a predictable and controlled degradation rate and did not cause any obstructive fragments. However, further studies are needed to improve the anchoring system and reduce the risk of bacterial colonization.

Abdominal and pelvic radiographs of medical devices and materials- part 2: neurologic and genitourinary devices and materials

Radiographs of the abdomen and pelvis are routinely obtained as a standard part of clinical care for the abdomen and pelvis. Brisk advances in technology over the last few decades have resulted in a multitude of medical devices and materials. Recognizing and evaluating these devices on abdominal and pelvic radiographs are critical, yet increasingly a difficult endeavor. In addition, multiple devices serving different purposes may have a similar radiographic appearance and position causing confusion for the interpreting radiologist. The role of the radiologist is to not only identify accurately these medical objects, but also to confirm for their accurate placement and to recognize any complications that could affect patient care, management or even be potentially life threatening. An extensive online search of literature showed our review article to be the most comprehensive work on medical devices and materials of the abdomen and pelvis, and in this second part of our two-part series, we discuss in depth about the neurologic and genitourinary devices seen on abdominal and pelvic radiographs.

Ureteral stent complications - experience on 50,000 procedures

Double J stent is an essential tool in urology, being a basic part of many urological procedures. However, some issues related to their use still occur. Our study aimed to evaluate an important number of procedures, the complications of ureteral stents, and their prevention and treatment retrospectively. We evaluate 50,000 procedures performed between 1996 and 2021 on 36,688 patients. According to the stenting duration, the cases were divided into short-term (less than 6 weeks – 34,213 procedures), respectively long-term stenting (more than 6 weeks – 15,757 procedures). The indications of stenting for both groups were noted. The total number of complications was 41,369. We encountered 153 cases (0.3%) of JJ stent malposition, of which 3 cases were into the retroperitoneum, one case with parenchymal perforation and hematoma. Considering the double J migrations, we found proximal migration in 427 cases (0.9%) and distal double J migrations in 352 (0.7%) cases. The obstruction of the ureteral stent, causing inefficient drainage, was encountered in 925 cases, while irritative bladder symptoms occurred in 16,326 cases (32.7%). Hematuria was observed in 5,213 cases, in 7 cases blood transfusion being necessary. Urinary tract infection was diagnosed in 7,436 cases (14.8%). Stent encrustation and calcification occurred in 832 cases, while stent fragmentation was noted in 52 cases. Double J stent complications should be promptly evaluated and treated. Encrustation and stone formation in forgotten stents often lead to serious complications and should be managed with stent removal and combined endourological techniques.

Proximal migration of a 'double J' ureteric stent in a patient with a staghorn calculus

Ureteric stents are widely used for the management of obstructive uropathy and intraoperative identification of the ureters. Despite undergoing numerous modifications since their introduction in 1967, they are frequently associated with complications ranging from irritative symptoms to migration of the stent. Proximal migration of ureteric stents is a relatively uncommon occurrence, with a reported incidence of 1–4.2%; it is usually associated with inappropriate stent length, poor positioning or incorrect deployment of the stent. Here we discuss an interesting case of a patient who unfortunately suffered proximal ureteric stent migration associated with pelvico-ureteric junction obstruction, despite appropriate stent choice, adequate deployment and confirmation of correct positioning. This complication likely occurred secondary to mechanical disruption of the stent caused by the presence of a large staghorn calculus within the renal pelvis.

A comparison between short- and long-term D-J stent in Anderson-Hynes pyeloplasty for pelvi-ureteric junction obstruction

PURPOSE

A double-J (D-J) stent is usually kept in situ during Anderson-Hynes (A-H) pyeloplasty for pelvi-ureteric junction (PUJ) obstruction. The aim of the study is to determine whether early removal of D-J stent is better than long-term stenting.

METHODS

In this prospective comparative study, conducted from January 2018 to April 2019 in Chittagong Medical College Hospital, patients with PUJ obstruction, age less than 12 years, were divided into group A (long-term stenting) and group B (short-term stenting) by simple randomization. Main outcome variables were urinary tract infection (UTI), stent colonization, encrustation, renal cortical thickness, differential renal function (DRF), glomerular filtration rate (GFR), and flow rate in DTPA renogram.

RESULTS

There were 31 patients in each group. Median age was 5 years (IQR: 2.3 to 7 years) and male to female ratio was 2.1:1. Frequency of post-operative UTI and stent colonization were significantly higher in group A than group B (p < 0.001). All the patients of both groups had similar improvement in renal cortical thickness, DRF, GFR, and flow rate. The study was potentially limited by its small sample size and high median age (5 years).

CONCLUSION

Early removal of D-J stent had lower incidence of UTI, stent colonization, encrustation, and stent migration.

Association of acute pyelonephritis with double-J ureteral stenting: a nationwide population-based case control study

OBJECTIVE

Urinary Tract Infections (UTIs) due to ureteral catheters has been frequently seen. The risk factors of this include both timing and those of the female gender. However, the association of Acute Pyelonephritis (APN) with use of ureteral DJ stents has rarely been investigated.

Materials and Methods: This study enrolled a total of 6,459 patients who were being treated with a ureteral catheter over a 10 year period from the nationwide database of Taiwan's National Health Insurance Bureau. From these subjects, episodes of APN were found in a total of 500 patients. Additionally, 2,000 patients without APN were randomly enrolled as a control group in order to analyze the associated factors.

RESULTS

The results indicate that the percentage of those with regards gender, age, duration of implantation, ureteral stent type, hypertension, T2DM, presence of urinary tract infection, benign prostate hyperplasia and pregnancy status were significantly statistically higher in APN patients than non-APN patients. APN did not associate with the use of antibiotics, urolithiasis, chronic kidney disease, malignancy, or uric acid stone in patients with a ureteral catheter.

Conclusion: In conclusion, patients with a ureteral catheter associated with APN should be given close attention with regards to the above risk factors. Early removal of the catheter is the best policy for the prevention of APN.

Placement of ureteral stents in three rabbits for the treatment of obstructive ureterolithiasis

Management of ureteral obstruction with stenting is often associated with a lower rate of complications than ureterotomy in domestic carnivores, but this treatment has not been previously evaluated in rabbits. Three rabbits (7, 6 and 10 years old) were diagnosed with unilateral obstructive ureterolithiasis associated with hydronephrosis and hydroureter on abdominal ultrasound. Decreased overall renal function was confirmed in all three cases. Ureteral stents were placed retrogradely via cystotomy without complication in two cases and anterogradely via nephrostomy in the third case. Survival after stent placement was 30, 3 and 8 months, with encrustation of the stent and re-obstruction occurring 18, 1 and 6 months after stent placement in successive cases. Ureteral stenting can be considered for short-term management of ureterolithiasis in rabbits to improve renal function and maintain quality of life. Ultrasound or radiographic monitoring is recommended to detect encrustation of the stent. Studies comparing ureteral stenting to ureterotomy in rabbits are needed to determine the effectiveness of these techniques.

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

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

When the bowel meets the bladder: Optimal management of colorectal pathology with urological involvement

Fistulae between the gastrointestinal and urinary systems are rare but becoming increasingly more common in current surgical practice. They are a heterogeneous group of pathological entities that are uncommon complications of both benign and malignant processes. As the incidence of complicated diverticular disease and colorectal malignancy increases, so too does the extent of fistulous connections between the gastrointestinal and urinary systems. These complex problems will be more common as a factor of an aging population with increased life expectancy. Diverticular disease is the most commonly encountered aetiology, accounting for up to 80% of cases, followed by colorectal malignancy in up to 20%. A high index of suspicion is required in order to make the diagnosis, with ever improving imaging techniques playing an important role in the diagnostic algorithm. Management strategies vary, with most surgeons now advocating for a single-stage approach to enterovesical fistulae, particularly in the elective setting. Concomitant bladder management techniques are also disputed. Traditionally, open techniques were the standard; however, increased experience and advances in surgical technology have contributed to refined and improved laparoscopic management. Unfortunately, due to the relative rarity of these entities, no randomised studies have been performed to ascertain the most appropriate management strategy. Rectourinary fistulae have dramatically increased in incidence with advances in the non-operative management of prostate cancer. With radiotherapy being a major contributing factor in the development of these complex fistulae, optimum surgical approach and exposure has changed accordingly to optimise their management. Conservative management in the form of diversion therapy is effective in temporising the situation and allowing for the diversion of faecal contents if there is associated soiling, macerated tissues or associated co-morbidities. One may plan for definitive surgical intervention at a later stage. Less contaminated cases with no fibrosis may proceed directly to definitive surgery if the appropriate expertise is available. An abdominal approach with direct repair and omentum interposition between the repaired tissues has been well described. In low lying fistulae, a transperineal approach with the patient in a prone-jack knife position provides optimum exposure and allows for the use of interposition muscle grafts. According to recent literature, it offers a high success rate in complex cases.