[The Allium ureteral stent in the management of ureteral stenoses, a retrospective, multicenter study]

Metal ureteral stents for ureteral stricture: 2 years of experience with 246 cases

BACKGROUND

Metal ureteral stents (MUS) has gained popularity as an endoscopic treatment alternative for the management of ureteral strictures. The aim of this study was to evaluate the safety, efficacy, and tolerability of MUS for treating ureteral strictures and to identify any factors that could influence the success of this intervention.

METHODS

This study is a prospective analysis of the efficacy and safety of MUS for treating ureteral strictures in a single-center setting. The study enrolled 246 patients who had been diagnosed with ureteral strictures and had undergone MUS placement between January 2019 and July 2021. The patients were followed-up for a duration of 2 years.

RESULTS

The overall success rate of MUS placement was 71.7%. Furthermore, the success rate of ureteral strictures after kidney transplantation (78.2%) was significantly higher than common ureteral strictures (73.0%) or recurrent ureteral strictures (67.6%). Additionally, postsurgery, there was a considerable reduction in hydronephrosis volume (68.9±96.1 vs. 32.1±48.8 cm 3 ), blood creatinine level (103.7±49.8 vs. 94.4±47.5 mol/l) and urea nitrogen level (6.7±7.2 vs. 5.1±2.4 mmol/l). The study also reported that the rate of adverse events associated with MUS was relatively low, included hematuria (7.9%), pain (6.8%), urinary tract infection (6.4%), and lower urinary tract symptoms (5.3%).

CONCLUSIONS

MUS appear to be a safe and effective treatment option for ureteral strictures, with a high success rate and low complication rate. These results have important implications for the management of ureteral strictures and can help guide clinical decision-making in the selection of treatment options.

Allium® ureteral stent, a new player in the treatment of ureteral stenosis: a prospective cohort study

INTRODUCTION AND OBJECTIVES

Ureteral stricture is a chronic condition that can result in the obstruction of urinary drainage from the affected renal unit, leading to loss of renal function. Treatment methods can be categorized into two main headings: endourological and reconstructive procedures. We aimed to investigate the efficacy and safety of the self-expandable Allium® ureteral stent, which has been used in the minimally invasive treatment of ureteral stenosis in recent years.

MATERIALS AND METHODS

Twenty patients who were applied Allium® ureteral stent between 2017 and 2021 included in the study. The demographic and clinical characteristics of the patients, the details of the treatments applied to the patients, the perioperative and postoperative complications, the treatments applied for the complications and the findings in the follow-up were recorded and evaluated prospectively.

RESULTS

Etiology included urolithiasis in 16 patients (80%), malignancy in 3 patients (15%), and a previous gynecological operation in 1 patient (5%). Stent obstruction was found to be the most common complication in 3 patients (15%). Stent migration was the second most common complication in 2 patients (10%). Our follow-up continues with 15 patients without stent-related complications and stent obstruction. The mean follow-up period was 28 ± 15.7 months.

CONCLUSIONS

Allium ureteral stent is an effective and reliable method in the minimally invasive treatment of ureteral stricture with complications seen at acceptable rates and ease of treatment in the management of complications.

[Long-term efficacy evaluation of coated metal stent implantation for ureteroscopic lithotripsy related refractory ureteral stricture]

OBJECTIVE

To comprehensively evaluate the long-term efficacy and safety of coated metal stent implantation for ureteroscopic lithotripsy related refractory ureteral stricture (URL-rUS).

METHODS

Electronic medical records of 30 patients (31 affected renal units) receiving coated metal stent implantation for URL-rUS from Sept. 2018 to Aug. 2021 at Peking University People' s Hospital were reviewed for analysis. Coated metal stents were implanted in retrograde approach via ureteroscope. Last outpatient follow-up was set as endpoint. Baseline information, stricture characteristics and decompression strategy before coated metal stent implantation were retrospectively collected. Serum creatinine (Scr) concentration and renal pelvis width (RPW) were used as renal function indicators. Peri-operative and long-term complications and according outcomes were recorded. For the patients who had double J tubes implanted for drainage before operation, Ureteral Stent Symptom Questionnaire (USSQ) was applied to evaluate the stent-related discomforts and quality of life (QoL) before and after surgery. Data analysis was conducted with SPSS (version 25.0; SPSS, Chicago, IL, USA).

RESULTS

Totally 30 patients with 31 affected renal units were included. All the patients previously underwent unsuccessful traditional endoscopic balloon dilation or endoureterotomy before receiving coated metal stent implantation. The mean age was (45.5±9.3) years old. The median follow-up time were 14 (6-36) months. All coated metal stents were successfully placed with a median duration of 60 (30-195) min. No severe peri-operative complications occurred. At endpoint, 28 (90.3%) sides of coated metal stents remained unobstructed with a longest indwelling time of 36 months. Causes of failures included stent migration (1 case, 3.2%), encrustation (1 case, 3.2%) and repeated stent related urinary tract infection (1 case, 3.2%). When compared with the baseline, significant reductions were observed in both Scr concentration and RPW at endpoint [(90.7±19.5) mmol/L vs. (83.1±18.5) μmol/L, P < 0.01, for Scr; (2.5±1.3) cm vs. (1.9±0.8) cm, P < 0.01, for RPW], indicating good preservation of renal function and remission of hydronephrosis. For 26 patients with double J stents before operation, significant reduction of USSQ average score (100.4±6.6 vs. 82.1±4.9, P < 0.01) evidenced better life quality preserving ability of coated metal stent versus double J stent.

CONCLUSION

Coated metal stent implantation is a safe and minimally invasive management of ureteral stricture providing a satisfying long-term patency rate, after which the patients' quality of life and renal function could be both improved. This method could serve as a promising alternative long-term maintenance treatment option for patients with URL-US, especially when traditional endoscopic interventions failed.

Analysis of long-term effect of ureteral balloon dilatation combined with internal and external drainage tube in the treatment of benign ureteral stricture

Purpose

There are few reports about balloon dilatation combined with internal and external drainage tube in the treatment of ureteral stricture under interventional therapy. The aim of the study is to explore the safety, effectiveness and long-term efficacy of this treatment strategy.

Materials and methods

It is a retrospective and observational study. From October 2013 to October 2016, 42 patients with benign lower ureteral stricture received interventional treatment. Balloon dilatation combined with internal and external drainage tube implantation were used. There were 25 male patients and 17 female patients. There were 7 cases (16.7%) with congenital ureteral stricture, 12 cases (28.6%) with inflammation, 15 cases (35.7%) with ureteral stricture after lithotomy or lithotripsy, and 8 cases (19.0%) with ureteral stricture after pelvic or abdominal surgery. After the drainage tube was removed, B ultrasound, enhanced CTU or IVP of urinary system were reexamined every six months. The follow-up time was 12–60 months.

Results

The age was 52.9 ± 11.6 years. The length of ureteral stricture was 1.1 ± 0.5 cm. 42 patients completed interventional treatment, the technical success rate was 100%, no ureteral perforation, rupture or other complications were identified. Preoperative urea nitrogen 9.2 ± 2.3 mmol/L and creatinine 175.8 ± 82.8umol/L. Urea nitrogen and creatinine were 3.8–9.1 mmol/L and 45.2–189.6 umol/L when removing the drainage tube. There were significant differences in the levels of urea nitrogen and creatinine before and after tube removal (P < 0.05). The ureteral patency rate was 100% at 6 months, 93% at 12 months, 83% at 18 months, 79% at 24 months, 76% at 30 months and 73% at 36–60 months. The overall success rate was 73%. Multivariate Cox regression analysis showed that stenosis length was a risk factor for postoperative patency (P < 0.05).

Conclusion

Balloon dilatation combined with internal and external drainage tube implantation in the treatment of benign lower ureteral stricture is safe and effective.

Initial Experience of Self-Expanding Metal Ureteral Stent in Recurrent Ureteral Stricture After Ureteroplasty

Background: The aim of this prospective study was to assess the safety and effectiveness of self-expanding metal ureteral stent (MUS) for the treatment of recurrent ureteral stricture after ureteroplasty.

Methods: We prospectively included 24 patients who underwent MUS implantation between February 2019 and August 2020. The inclusion criteria for the procedure were recurrent ureteral strictures after ureteroplasty. A paired T test was used to compare continuous variables before and after surgery.

Results: A total of 24 patients were finally included in this study. The stricture site was most common on the proximal ureter 19 (79.2%), followed by distal ureter 4 (16.7%) and middle ureter 1 (4.2%). The median length of ureteral stricture is 2.5 (range 1–18) cm. The median operative time was 51.5 min, and the median hospital stay time after surgery was 3 days. Post-operative complication included pain 1 (4.2%), urinary tract infection 2 (8.3%) and hematuria 2 (8.3%). After a median follow-up of 12 months, 19/24 (83.3%) patients were clinically and radiologically successful. We endoscopically adjusted or exchanged the failed stents. The volume of hydronephrosis (124.7 ± 132.5 vs. 66.4 ± 73.2 cm³, P = 0.015), blood creatinine level (104.5 ± 45.4 vs. 80.1 ± 23.2 μmol/L, P = 0.044) and urea nitrogen level (6.9 ± 2.4 vs. 4.8 ± 1.5 mmol/L, P = 0.003) decreased significantly after a median follow-up of 12 months.

Conclusions: MUS is a safe and effective way to manage recurrent ureteral strictures after ureteroplasty. This technique provides a new choice for the treatment of recurrent stricture.

Self-expanding metal ureteral stent for ureteral stricture: Experience of a large-scale prospective study from a high-volume center - Cross-sectional study

BACKGROUND

The management of ureteral stricture is still a challenge for urologists. The aim of this prospective study was to assess the safety and effectiveness of self-expanding metal ureteral stents (URS) in ureteral strictures.

METHODS

We performed URS placement procedures for ureteral stricture from Jan 2019 to July 2020, and prospectively collect various data before and after the operation. A paired T test was used to compare continuous variables before and after surgery, binary logistic regression analysis was used to identify the independent risk predictors of surgical failure.

RESULTS

A total of 147 patients with 157 renal units received successful placement of URS. The mean operative time was 70.0 min. After a median follow-up time of 15 months, 73.2% (115/157) of stents were kept in situ. The most common complication was hematuria (13, 8.8%), followed by urinary tract infection (11, 7.5%) and pain (8, 5.4%). The volume of hydronephrosis (67.9 ± 34.9 VS 34.9 ± 51.1 cm³, P = 0.0001), serum creatinine level (103.0 ± 54.5 VS 93.8 ± 45.1 μmol/L, P = 0.034) and blood urea nitrogen level (6.6 ± 6.7 VS 5.4 ± 2.4 mmol/L, P = 0.032) decreased significantly at last follow up when compared with baseline. Stricture of the distal ureter was an independent risk factor for stent failure (HR 1.77, 95% CI 1.15, 2.73, P = 0.009).

CONCLUSIONS

URS was found to be safe and effective for ureteral strictures with a limited complications and good long-term results. For those who are not suitable for surgical reconstruction, the URS is an alternative management.

Recommendations of the AFU Infectious Diseases Committee on the prevention, diagnosis and treatment of infections of endo-ureteral equipment

INTRODUCTION

No recent national guidelines exist regarding the management of urinary tract infections (UTIs) in the presence of ureteral stent. This situation could lead to discrepancies in clinical management and less opportunity for a favorable patient's outcome.

METHODS

All available data published on Medline® between 1998 and 2018 were systematically searched and reviewed. All papers assessing adult patients carrying ureteral stent were included for analysis. After studies critical analysis, national guidelines for clinical management were elaborated in order to answer clinical questions.

RESULTS

A total of 451 articles were identified, of which 58 have been included. The prevalence of urinary tract infections in the presence of ureteral stent remains unknown. After 3 months, all endo-ureteral devices were colonized on microbiological study. These patients also presented a positive urine culture in 25 to 70% of the cases, often polymicrobial. Staphylococci, E. coli, Klebsiella, Pseudomonas, Enterococcus and Candida were the commonest micro-organisms responsible for urinary colonization or infection. The risk of UTI on endo-ureteral devices seemed higher the longer it stayed implanted. There is no justification in the literature to recommend a systematic change of endo-ureteral devices following a urinary tract infection.

DISCUSSION

The existing literature is rich but of poor methodological quality, and therefore does not allow to draw robust conclusions. The greatest difficulty faced in this work was to accurately differentiate urinary colonizations from true infections, including clinical symptoms and not only microbiological results.

CONCLUSION

These guidelines propose a standardized management of such common clinical situations. Well-designed studies are needed to upgrade the level of evidence of these guidelines.

A systematic review of long-duration stents for ureteral stricture: which one to choose?

OBJECTIVE

To define which long-term stent would work best in malignant ureteral obstruction (MUO) and benign ureteral obstruction (BUO), focusing on their mechanisms of action, price and insertion approach.

METHODS

A systematic review was developed using the MEDLINE and Scopus databases and in accordance with the PRISMA checklist. There were no language restrictions for the search. Studies describing the use of metallic ureteric stents for MUO and for BUO in humans were included.

RESULTS

We analyzed five types of metallic stents (35 papers) and also the experience with the tumor and extra-anatomical stents. The Resonance, Memokath and Allium ureteral stents were found to be useful in BUO and MUO. The Uventa stent performed well in chronic ureteral obstruction. The Detour bypass stent was a recommended option in those patients who had complete obstruction of the ureter and were unfit for reconstructive surgery. There was no difference with regard to the insertion technique and both antegrade and retrograde approaches were equally successful. Although tumor stents showed a good performance, there were very few published studies on it.

CONCLUSION

Metallic stents are a suitable option for MUO and BUO. When compared to standard double J stents, although they are relatively high priced, they show a financial benefit in the long-term. The Detour bypass stent seems to be an effective alternative for complete ureteral obstruction or patients unfit for surgery. Further prospective randomized studies should be done on the effectiveness of tumor stents versus metallic stents.

[Initial clinical experience and follow-up outcomes of treatment for ureteroileal anastomotic stricture with Allium coated metal ureteral stent]

OBJECTIVE

To summarize the initial clinical experience and follow-up results of the treatment for ureteroileal anastomotic stricture after radical cystectomy with Allium coated metal ureteral stent.

METHODS

From September 2018 to September 2019, 8 patients with ureteroileal anastomotic stricture after radical cystectomy underwent Allium ureteral stent insertion in Peking University People's Hospital and People's Hospital of Daxing District. The preoperative renal pelvis width under ultrasound was collected to evaluate the postoperative hydronephrosis, creatinine and urea nitrogen (BUN) before and after surgery, perioperative infection, and stent-related complications. The serum creatinine and BUN, renal pelvis width under ultrasound, urography and abdominal plain film (KUB) were reviewed at the end of 1, 3, and 6 months and annually postoperatively to observe the stent position and morphology. The long-term stent patency rate, complication rate, renal function and hydronephrosis were followed up and analyzed. The t-test or rank-sum test was used to compare the measurement data of the matched sample from the preoperative to the last follow-up.

RESULTS

In the study, 6 cases (7 sides) were ureteral ileal conduit stricture, and 2 cases (3 sides) ureteral orthotopic neobladder stricture. Before surgery, 5 patients underwent long-term indwelling of a single J ureteral stent, with an average indwelling time of (20.6±8.8) months and an average replacement frequency of (3.6±1.3) months/time. The mean width of renal pelvis was (26.5±9.1) mm on preoperative renal ultrasonography. Among them, 6 patients were successfully indwelled with Allium coated metal ureteral stent by retrograde approach, and 2 patients by combination of double-endoscopy and ante-retrograde approach. No surgery-related complications during perioperative period were observed. The mean follow-up period was 9.8 months and Allium stent and ureter remained unobstructed in all the patients at the last follow-up without replacement or removal. Compared with preoperative data, the mean width of renal pelvis and mean blood urea nitrogen (BUN) in the last follow-up period were significantly reduced [(26.5±9.1) mm vs. (13.4±2.5) mm, P=0.008; (11.6±2.3) mmol/L vs. (10.2±2.2) mmol/L, P=0.017], however, there were no significant differences in the average serum creatinine or hemoglobin (P>0.05). Ureteroileal anastomotic re-stricture and other stent-related complications were not observed in all the patients by antegrade urography.

CONCLUSION

Allium coated metal ureteral stent could be used for the treatment for ureteroileal anastomotic stricture, which could maintain relatively long-term patency rate and protect renal function. The indwelling time was longer and it could improve quality of life of patients.

Endoscopic Management of Ureteral Strictures: an Update

PURPOSE OF REVIEW

This review focuses on the role of endoscopic treatment of ureteral stricture disease (USD) in the era of minimally invasive surgery.

RECENT FINDINGS

There is a relative paucity of recent literature regarding the endoscopic treatment of USD. Laser endopyelotomy and balloon dilation are associated with good outcomes in treatment-naïve patients with short (< 2 cm), non-ischemic, benign ureteral strictures with a functional renal unit. If stricture recurs, repetitive dilation and laser endopyleotomy is not recommended, as success rates are low in this scenario. Patients with low-complexity ureteroenteric strictures and transplant strictures may benefit from endoscopic treatment options, although formal reconstruction offers higher rates of success. Formal ureteral reconstruction remains the gold-standard treatment for ureteral stricture disease as it is associated with higher rates of complete resolution. However, in carefully selected patients, endoscopic treatment modalities provide a low-cost, low-morbidity alternative.

Loss of Renal Function After Retrograde Ureteral Placement of an Allium Stent for Severe Ureteral Stricture

Background: Ureteral strictures are a recurrent chronic condition that leads to severe side effects and poor quality of life. Management of ureteral stricture is a great challenge for urologists and no specific guidelines exist. Retrograde Allium^® ureteral stent (AUS) is a newly developed ureteral stent to treat either bulbar urethral or ureteral stenosis.

Case Presentation: We describe a case of a 74-year-old Caucasian adult male presenting with a severe ureteral stricture secondary to an ureteroscopy for stone disease. Treatment with retrograde AUS placement produced a complete loss of renal function after 36 months, probably because of the development of a long achalasic stretch of the ureter.

Conclusions: AUS is a new and promising device for the treatment of ureteral stenosis. However, a lack of standardization of the technique recommends a close instrumental follow-up after the procedure to decide the optimal time for stent removal.

Allium stent for the treatment of a malignant ureteral stenosis: A paradigmatic case

OBJECTIVE

The aim of this study was to present a paradigmatic case where the new-generation Allium URS stent was the optimal choice to treat a malignant ureteral stenosis.

METHODS

We describe in detail all the steps of our surgery, performed on a 69-year-old patient with left hydronephrosis caused by lumbo-aortic nodal metastases compressing the ureter. The patient was intolerant to double-J stent due to strong irritative urinary symptoms. Allium URS stent was positioned under fluoroscopy in replacement of pre-existing double-J stent.

RESULTS

Our approach was successful and irritative urinary symptoms disappeared. At 6 months, the Allium URS was correctly positioned and no hydronephrosis was detected on ultrasound. The stent can be left in place for a maximum of 3 years.

CONCLUSIONS

In complicated scenarios of chronic ureteral stenosis, the new-generation Allium URS can be an interesting option to treat the obstruction while sparing the patient the irritative urinary symptoms and periodic replacements typical of a double-J stent.