Late ureteral obstruction after endoscopic treatment of vesicoureteral reflux with polyacrylate polyalcohol copolymer

Endoscopic injection of bulking agents in pediatric vesicoureteral reflux: a narrative review of the literature

In the last 20 years, endoscopic injection (EI) has affirmed as a valid alternative to open surgery for management of pediatric vesicoureteral reflux (VUR). This study aimed to investigate and discuss some debated aspects such as indications, bulking agents and comparison, techniques of injection and comparison, predictive factors of success, use in specific situations. EI is minimally invasive, well accepted by patients and families, with short learning curve and low-morbidity profile. It provides reflux resolution rates approaching those of open reimplantation, ranging from 69 to 100%. Obviously, the success rate may be influenced by several factors. Recently, it is adopted as first-line therapy also in high grade reflux or complex anatomy such as duplex, bladder diverticula, ectopic ureters. The two most used materials for injection are Deflux and Vantris. The first is absorbable, easier to inject, has lower risk of obstruction, but can lose efficacy over time. The second is non-absorbable, more difficult to inject, has higher risk of obstruction, but it is potentially more durable. The two main techniques are STING and HIT. To date, the ideal material and technique of injection has not yet clearly established, but the choice remains dependent on surgeon's preference and experience.

A systematic review & meta-analysis comparing outcomes of endoscopic treatment of primary vesico ureteric reflux in children with polyacrylate poly alcohol copolymer versus dextranomer hyaluranic acid

BACKGROUND & AIMS

There are conflicting reports on the efficacy of bulking agents for vesico ureteric reflux (VUR). In this meta-analysis we have compared the outcomes of endoscopic treatment with polyacrylate polyalcohol copolymer (PPC) and dextranomer hyaluronic acid (DxHA).

METHODS

A systematic review of publications between 2010 and 2020 was conducted covering databases like PUBMED, MEDLINE etc. for (endoscopic treatment) AND (VUR) AND (PPC OR DxHA) AND (recurrence OR complications). PRISMA guidelines were followed and only comparative studies were included. Outcomes were early success defined as absence of VUR in voiding cystourethrogram at 3-months followup, urinary tract infections (UTI) and occurrence of vesico-ureteric-junction obstruction (VUJO). Risk of bias was analysed with Robvis tool and odds-ratios were compared with Revman-3.0.

RESULTS

Among nine studies (heterogeneity; I 2 69-79%) all cleared the risk of bias assessment. There was no significant difference in high grade VUR (p = 0.94) between PPC (40%) and DxHA (43%). Success rate after single injection was significantly higher (p = 0.0001) at 86% (477/555) for PPC vs 69% (474/685) for DxHA. UTI rate between PPC (12%) and DxHA (14.6%) was not statistically significant (p = 0.54). VUJO rate between PPC (3.9%) and DxHA (0.8%) was also not significantly different (p = 0.47). Significantly lesser volume (p = 0.02) was used for PPC (0.7 ml) compared to DxHA (0.9 ml).

CONCLUSION

Reflux resolution was significantly higher with PPC than DxHA. Postinjection UTI/VUJO incidence was not significantly different between them. Limitation of this meta-analysis was heterogeneity & small number of articles. Further studies should focus on long-term outcomes and cost-effectiveness.

Is lower urinary tract surgery without upper pole heminephrectomy safe and effective in the long-term treatment of duplex system ureterocele?

Objective:

The study aimed to retrospectively evaluate postoperative results of patients with duplex system ureterocele (DSU) who underwent endoscopic ureterocele incision (UI), lower urinary tract reconstruction (LUTR) or both, and investigate the necessity of upper pole heminephrectomy (UPH) in ureterocele treatment.

Patients and methods:

In total, 44 patients with DSU who were operated on in December 2005 and December 2018 were evaluated for patient characteristics, ureterocele location, differential renal function (DRF), vesicoureteral reflux (VUR), postoperative incontinence, proteinuria, hypertension and urinary tract infection (UTI).

Results:

UI was performed in 27 of 44 cases (61.3%) as the first-line treatment. Ten of them (37%) had no urinary infection or renal function loss at a mean of 3 years (1.5–7 years). LUTR was needed in 17 patients after UI due to VUR in 14 patients and bladder outlet obstruction (BOO) in 3 patients. In total, 34 patients who underwent LUTR, proteinuria or incontinence were not detected in the mean 6 years’ follow-up. Thirty-three patients (97%) had identical renal scans and similar DRF before and after the operation. No patient underwent UPH.

Conclusion:

UI must be considered the first-line treatment in DSU in infancy. In older patients, especially with VUR, LUTR is effective and safe and UPH mostly is not necessary.

Level of evidence:

4

Endoscopic treatment of primary vesicoureteral reflux in children with two different bulking agents, high success and low complication rates: Comparison of Dexell and Vantris

INTRODUCTION AND OBJECTIVES

To compare the results in terms of efficacy and safety of the endoscopic management for vesicoureteral reflux (VUR) in two different standardized primary VUR cohorts treated with Dexell and Vantris.

PATIENTS

128 refluxing renal units (RRU) in 87 patients with primary VUR (64 females, 23 males). Patients with secondary VUR and severe bladder and bowel dysfunction were excluded. A total of 22 continent children with mild bladder-bowel dysfunction underwent bladder-bowel training before the implantation. All procedures were performed in the presence of sterile urine using a conventional subureteral transurethral injection technique.

RESULTS

There were no statistically significant differences between groups in terms of mean age, sex, RRU side, ^99mTc-DMSA uptake, and reflux grade. The overall resolution rates based on the number of RRUs for up to three endoscopic treatments were 80% (56/70) in Dexell group and 94.8% (55/58) in Vantris group (P = .012). No postoperative recurrences or vesicoureteral junction obstructions were seen in any group.

CONCLUSIONS

Dexell and Vantris provided an effective and safe endoscopic VUR treatment in the early and mid-term follow up of children with primary VUR. The effectiveness of these substances, which can produce different mass effects with different particle sizes, in safe VUR resolution, needs further investigations.

Endoscopic Correction of Reflux Utilizing Polyacrylate Polyalcohol Bulking Copolymer (Vantris) as a Tissue Augmenting Substance: Lessons Learned Over the 10 Years of Experience

Objectives: To prove the hypothesis that modifying the endoscopic correction of vesicoureteral reflux (VUR) technique (STING procedure) and sharpening its contraindications, lead to increased success rate and decline in the complication rate. Materials and Methods: All patients that underwent endoscopic correction of VUR utilizing Vantris were divided into two groups according to procedure date; before 2015 and 2015-2019. Indication for treatment included persistent high-grade VUR or breakthrough infections. Contraindications included voiding dysfunction, active infection and since 2015 suspicion for obstructive/refluxing ureterovesical junction (UVJ) presented by "beak" sign on voiding cystourethrography (VCUG). Follow-up regiment included ultrasound and VCUG at predetermined intervals. Results: The first group included 215 (158 girls and 57 boys) children with mean age of 4.8 ± 2.8 years who underwent endoscopic correction between 2009 and 2015 and the second group included 42 children (28 girls and 14 boys) with mean age of 3.9 ± 2.1 years who underwent surgery between 2015 and 2019. In the first group, VUR was unilateral in 74 patients and bilateral in 132 comprising 338 renal refluxing units. In the second group, VUR was unilateral in 14 patients and bilateral in 30 comprising 74 RRUs. In the first group reflux was corrected in 317 (94.9%) RRUs after a single injection, after the second in 7 (2.1%) RRUs. In seven (2.1%) RRUs, reflux downgraded to Grade I-II. Three RRUs (0.9%) failed endoscopic correction and required ureteral reimplantation. Nine (2.7%) RRUs developed UVJ obstruction. In the second group reflux was corrected in 61 (82.4%) RRUs after a single injection, after the second in 12 (16.2%) RRUs. In one (1.4%) RRU, endoscopic correction failed and required ureteral reimplantation. None of the patients developed UVJ obstruction. Reflux correction has led to the significant decrease of febrile urinary tract infection (UTI) in both groups. Conclusions: Our data indicate that endoscopic injection utilizing Vantris is safe and long durable procedure. Although utilizing the proper technique and contraindication criteria, the rates of post procedural VUJ obstruction is null.

Endoscopic treatment of primary vesicoureteral reflux in children with two different bulking agents, high success and low complication rates: comparison of Dexell and Vantris

INTRODUCTION AND OBJECTIVES

To compare the results in terms of efficacy and safety of the endoscopic management for vesicoureteral reflux (VUR) in two different standardized primary VUR cohorts treated with Dexell and Vantris.

PATIENTS

128 refluxing renal units (RRU) in 87 patients with primary VUR (64 females, 23 males). Patients with secondary VUR and severe bladder and bowel dysfunction were excluded. A total of 22 continent children with mild bladder-bowel dysfunction underwent bladder-bowel training before the implantation. All procedures were performed in the presence of sterile urine using a conventional subureteral transurethral injection technique.

RESULTS

There were no statistically significant differences between groups in terms of mean age, sex, RRU side, 99mTc-DMSA uptake, and reflux grade. The overall resolution rates based on the number of RRUs for up to three endoscopic treatments were 80% (56/70) in Dexell group and 94.8% (55/58) in Vantris group (p = 0.012). No postoperative recurrences or vesicoureteral junction obstructions were seen in any group.

CONCLUSIONS

Dexell and Vantris provided an effective and safe endoscopic VUR treatment in the early and mid-term follow up of children with primary VUR. The effectiveness of these substances, which can produce different mass effects with different particle sizes, in safe VUR resolution, needs further investigations.

Endoscopic Injection Treatment of Vesicoureteral Reflux in Children: Meeting with the Factors Involved in the Success Rate

The challenges and controversies in vesicoureteral reflux intervention guidelines resulted in a more individualized treatment planning. Endoscopic injection therapy is now widely used and is considered preferable, but still remains less successful than ureteral reimplantation. Τhe endoscopic vesicoureteral reflux approach should be risk-adapted to current knowledge, so more experience and longer-term follow-up are needed. The precise of preoperative, intraoperative, and postoperative factors that affecting endoscopic injection therapy success rates and outcome have not yet been clearly determined. The aim of this study was to investigate these associated factors. Although the reflux grade is the most well-known factor that can affect the success of the procedure, there is no agreement on which factors are the most influential for the efficacy of endoscopic reflux treatment. So, we carried out a broad review of published papers on this topic, and we presented all the potential predictive variables of endoscopic reflux resolution in children.

Brazilian consensus on vesicoureteral reflux-recommendations for clinical practice

Introduction

Vesicoureteral Reflux (VUR) is characterized by a retrograde flow of urine from the bladder into the ureters and kidneys. It is one of the most common urinary tract anomalies and the major cause of urinary tract infection (UTI) in the first years of life. If not properly diagnosed and treated can lead to recurrent UTI, renal scar and, in severe cases, to end stage renal disease. Despite recent advances in scientific and technological knowledge, evaluation and treatment of VUR is still controversial and there is still considerable heterogeneity in evaluation methods and therapeutic approaches. The aim of the present consensus is to give a practical orientation on how to evaluate and treat VUR.

Methods

The board of Pediatric Urology of the Brazilian Society of Urology joined a group of experts and reviewed all important issues on Vesicoureteral Reflux evaluation and treatment and elaborated a draft of the document. On November 2017 the panel met to review, discuss and write a consensus document.

Results and Discussion

Vesicoureteral Reflux is a common and challenging problem in children. Children presenting with Vesicoureteral Reflux require careful evaluation and treatment to avoid future urinary tract infections and kidney scars. The panel addressed recommendations on up to date choice of diagnosis evaluation and therapies.

What are the predictive factors leading to ureteral obstruction following endoscopic correction of VUR in the pediatric population?

BACKGROUND

It is extremely important to not only address the short-term success following endoscopic correction of vesicoureteral reflux (VUR) but also the long-term efficacy and safety of the tissue augmenting substance utilized for endoscopic correction.

OBJECTIVE

This study retrospectively evaluated all cases of ureterovesical junction (UVJ) obstruction following endoscopic treatment of VUR over the last 5 years utilizing two tissue augmenting substances, with special emphasis on the safety of Vantris^®, and performed clinical and histological review of these patients.

METHODS

The study population comprised 2495 patients who underwent endoscopic correction of VUR utilizing Deflux^® (1790) and Vantris^® (705). Tissue sections were stained with hematoxylin & eosin and trichrome, and examined under a light microscope. Nine primary obstructive megaureters after ureteral re-implantation served as controls.

RESULTS

Nine (0.5%) children (three female and six male) in the Deflux group and nine (1.3%) (five females and four males) in the Vantris group developed UVJ obstruction and required ureteral re-implantation. Obstruction developed during the period ranging 2-49 months (average 16 months) following endoscopic correction. The primary reflux grade was III in seven, IV in six, and V in six children. The mean volume of the injected material in all obstructed patients was 1.2 ± 0.6 cc (mean ± SD). Histopathological analysis revealed a pseudocapsule composed of fibrous tissue and foreign-body giant cells surrounding the Vantris implant in all patients. The distal part of the ureters demonstrated significant ureteral dilatation without ureteral fibrosis. In all patients, additional biopsies from the muscularis propria adjacent to the injection site were examined and showed no significant abnormalities. There was an increased collagen deposition in the juxtavesical segment of the obstructive ureters following Deflux and Vantris injections, and of primary obstructive megaureter. No significant difference was found in the tissue response between Deflux and Vantris patients and controls. Statistical analysis of the nonhomogeneous population demonstrated higher obstruction rates in patients from the Vantris group. However, no statistical difference was demonstrated regarding the obstruction rate in the homogenous group with relation to gender, age and reflux grade group of patients. Moreover, univariate analysis revealed that Grade V reflux, the presence of beak sign on the reviewed pretreatment, and inflamed bladder mucosa upon injection were significant independent risk factors leading to obstruction.

DISCUSSION

This study suggested that the underlining ureteral pathology lead to UVJ obstruction following Vantris injection. There was increased collagen deposition in the juxtavesical segment of the obstructive ureters following Vantris injection. Furthermore, these findings were similar to those discovered in patients who underwent endoscopic correction with Deflux, and in patients who required ureteral reimplantation due to primary obstructive megaureter. Additional biopsies from the muscularis propria adjacent to the injection site showed no significant abnormalities, ironing out the fact that Vantris did not led to adverse tissue reaction following injection. Univariate analysis further ironed out the hypothesis that underlying ureteral pathology was responsible for the increased incidence of UVJ obstruction and demonstrated that Grade V reflux, the presence of beak sign on the reviewed pretreatment VCUG, and inflamed bladder mucosa upon injection were significant independent risk factors leading to obstruction.

CONCLUSION

Data showed that Vantris injection did not lead to any different ureteral fibrosis or inflammatory changes to the tissue augmenting substances utilized in past and present clinical practice, and therefore did not seem to increase the incidence of UVJ obstruction. High reflux grade, presence of obstructive/refluxing megaureter and inflamed bladder mucosa were the only statistically significant and independent predictive factors for UVJ obstruction following endoscopic correction of VUR.

Endoscopic correction of vesicoureteral reflux in children using polyacrylate-polyalcohol copolymer (Vantris): 5-years of prospective follow-up

Introduction

The endoscopic correction of vesicoureteral reflux (VUR) in children is a currently well accepted therapy in many pediatric urology centers. Polyacrylate-polyalcohol copolymer (PPC), namely Vantris^®, is one of the tissue-augmenting substances used for endoscopic reflux therapy. The aim of this study was to evaluate the results with PPC in children.

Material and methods

From 2012 to 2016, 125 children (73 girls and 52 boys) aged 0.6–17.9 years (mean 4.9 ±3.58) were treated with PPC. VUR was unilateral in 64 and bilateral in 61 patients, comprising 197 renal refluxing units (RRUs) grades: II in 72, III in 50, IV in 33 and V in 42. Of these primary reflux was present in 132 RRUs and 65 were complex cases. Voiding cystourethrogram (VCUG) was done 3 months after procedure.

Results

Follow-up was completed in 89.6% of patients (112 children), and 89.8% of RRUs (177 out of 197). Reflux resolved in 86.4% of RRUs after single injection, in 99.4% after second and in 100% after the third. The only significant, but serious complication observed was late ureteral obstruction after PPC injection correcting high grade reflux, which required ureteral re-implantation. This complication was found in 9 out of 112 children (8%), and in 11 out of 177 RRUs (6.2%), 1.1 -2.9 years (mean 2 ±0.7) after the PPC injection. The longest follow-up reaches 4.5 years.

Conclusions

Our data show that the PPC injection is an effective procedure for treating all grades of VUR with high success rate. However, because of the possibility of late ureteral obstruction, which requires ureteroneocystostomy, long-term follow-up is mandatory.

Endoscopic injection therapy

Since the U.S. Food and Drug Administration approved dextranomer/hyaluronic acid copolymer (Deflux) for the treatment of vesicoureteral reflux, endoscopic injection therapy using Deflux has become a popular alternative to open surgery and continuous antibiotic prophylaxis. Endoscopic correction with Deflux is minimally invasive, well tolerated, and provides cure rates approaching those of open surgery (i.e., approximately 80% in several studies). However, in recent years a less stringent approach to evaluating urinary tract infections (UTIs) and concerns about long-term efficacy and complications associated with endoscopic injection have limited the use of this therapy. In addition, there is little evidence supporting the efficacy of endoscopic injection therapy in preventing UTIs and vesicoureteral reflux-related renal scarring. In this report, we reviewed the current literature regarding endoscopic injection therapy and provided an updated overview of this topic.

Endoscopic treatment of grades IV and V vesicoureteral reflux with two bulking substances: Dextranomer hyaluronic acid copolymer versus polyacrylate polyalcohol copolymer in children

PURPOSE

We aimed at evaluating the efficacy and complications of two bulking substances: dextranomer/hyaluronic acid copolymer(Dx/Ha;Dexell®) versus polyacrylate polyalcohol copolymer(PPC;Vantris®) in subureteric injection treatment of children with high grades (grades IV-V) vesicoureteral reflux(VUR).

METHODS

Data of patients undergoing endoscopic treatment of high grade VUR (January 2009-August 2015) were retrospectively investigated. Patients with high grade VUR caused by posterior urethral valve, duplex system, paraureteral diverticula and neurogenic bladder were excluded. Classical subureteric injection method (STING) was used. Seventy-three children (45 girls and 28 boys) who had 88 refluxing renal units (RRUs) with grades IV-V VUR (n=64/n=24) underwent endoscopic treatment using Dx/Ha (n=63 RRUs) and PPC (n=25 RRUs).

RESULTS

Mean age of patients in Dx/Ha and PPC groups were 6 (3) and 6 (3.75) year (p=0.81), and volumes of these substances given were 1.3 (1) and 1 (0.5) mL (p=0.003), respectively. Overall, for the first endoscopic injection, success rate of grades IV-V VUR per RRU was 53.9% with Dx/Ha, compared to 80% in PPC-injected group, (p=0.024). Late ureterovesical junction obstruction developed only in one patient in PPC-injected group. No ureteral obstruction was observed in Dx/Ha-injected group.

CONCLUSIONS

Endoscopic injection of PPC resulted in significantly higher success rate, compared to Dx/Ha in subureteric injection treatment of children with high grade VUR. However, the development of late ureterovesical junction obstruction should also be taken into account in PPC injection.

The comparison of dextranomer/hyaluronic acid and polyacrylate-polyalcohol copolymers in endoscopic treatment of vesicoureteral reflux

BACKGROUND

Dextranomer/hyaluronic acid (Dx/Ha;Dexell®) and polyacrylate-polyalcohol copolymer (PPC;Vantris®) are the popular tissue-augmenting substances using for the endoscopic injections of vesicoureteral reflux (VUR). The aim of the study is to evaluate and compare Dx/Ha and PPC in terms of effectiveness, injection techniques and complications with special emphasis on vesicoureteral junction obstruction (VUJO).

METHODS

A total of 95 patients who underwent endoscopic VUR treatment between 2009 and 2015 were retrospectively reviewed. The patients were divided into two groups: group 1: Patients underwent endoscopic treatment with PPC (n=50 patients, 70 renal refluxing units) group 2: Patients underwent endoscopic treatment with Dx/Ha (n=45 patients, 74 renal refluxing units).

RESULTS

The overall resolution rates based on the number of renal refluxing units studied was 88.6% and 70.3% in group 1 and group 2, respectively. Resolution rates were significantly better in group 1 compared to group 2. VUJO requiring ureteral reimplantation or stent insertion developed in 7 patients in group 1. No VUJO was observed in group 2. VUJO in group 1 was markedly higher than that in group 2.

CONCLUSIONS

Endoscopic treatment of VUR with PPC promises better resolution rates but higher VUJO rates compared to Dx/Ha.