The use of polyacrylate-polyalcohol copolymer hydrogel in the endoscopic treatment of primary vesicoureteral reflux in children

Comparison of polyacrylate polyalcohol copolymer (PPC) and dextranomer/hyaluronic acid (Dx/HA) for treatment of vesicoureteral reflux. A systematic review and meta-analysis

PURPOSE

Our study aimed to compare the efficacy of polyacrylate polyalcohol copolymer and Dextranomer-Hyaluronic Acid for endoscopic treatment of vesicoureteral reflux.

MATERIAL AND METHODS

MEDLINE, EMBASE, Scopus, Web of science, Ovid, Cochrane databases, Google scholar have been searched for studies published until January 2022 in any language. Studies that compared the success rate for endoscopic treatment of vesicoureteral reflux in children with two bulking agents, namely, "polyacrylate polyalcohol copolymer." and "Dextranomer-Hyaluronic Acid" were included for this analysis.

RESULTS

Nine studies were included in data synthesis for this meta-analysis. Pooled data with a total of 763 ureters in PPC group and 718 ureters in Dx/HA group indicated that ureters in PPC group were more likely to undergo complete reflux resolution than Dx/HA (OR 3.80, 95% CI: 2.71; 5.31). Among subgroup of patients with high grade reflux, PPC injection had more resolution rate compared to Dx/HA patients (OR: 2.92, 95% CI: 1.19-7.16). In total, 95.81% of the PPC group and 86.52% of the Dx/HA group experienced success after the third injection. However a concerning complication of endoscopic treatment which is ureterovesical junction obstruction (UVJO) was more prevalent in PPC group. So the possible benefits arising from endoscopic treatment with PPC could be offset by the costs of re-implantation surgery or stenting in the case of UVJO.

CONCLUSION

These data indicate that PPC injection for vesicoureteral reflux treatment was associated with a higher success rate, but concerningly, UVJO incidence was higher in the PPC group which might negate the possible benefits of PPC injection However, due to the lack of studies with long-term follow-up, we couldn't reach a definitive conclusion about the superiority of one of the bulking agents over the other.

Risk factors for obstructive complications after endoscopic correction of vesico-ureteral reflux using polyacrylate polyalcohol copolymer

Use of polyacrylate-polyalcohol copolymer (PPC) after endoscopic correction (EC) of vesico-ureteral reflux (VUR) is highly effective but is associated with a higher risk of obstructive complications (OC) compared with other implants. We undertook a STROBE compliant retrospective investigation and studied the OC risk factors to increase the practical safety of PPC.Overall, 798 patients (464 [58.1%] girls and 334 [41.9%]) boys) from 5 hospitals in whom PPC was routinely used were evaluated retrospectively. The patients were subdivided into 2 groups. Group I consisted of 754 (94.5%) children (449 [59.5%] girls and 305 [40.5%] boys) without OC. Median age was 41 months [Q1: 18.0; Q3: 81.0]. Group II comprised 44 (5.5%) patients (29 [65.9%] boys and 15 [34.1%] girls) experiencing OC, and their median age was 21.5 months [Q1: 12.0; Q3: 43.0]. Clinical and renal ultrasound examinations were carried out 1 day and 1 month after EC, and then every 6 months after EC. At the follow-up examination approximately 6 months after EC, voiding cysto-urethrography (VCUG) was performed. All patients with OC underwent diuretic renography.OC occurred in 44 (5.5%) of 798 children, in some cases as late as 60 months after endoscopic injection of the bulking agent PPC for correction of VUR. Univariate analysis revealed that younger age (P < .001), higher grade of VUR (P < .001), male gender (P < .001), second injection (P = .003), and EC injection using hydrodistension implantation technique (HIT; P < .001) represented significant risk factors. At multivariate analysis, only male gender (P = .0078), younger age (P = .0044), HIT technique (P < .0001), and second injection (P = .04) represented significant risk factors for the occurrence of OC.We identified young age, male gender, high reflux grade, HIT technique, and second endoscopic injections as factors associated with the risk of OC after EC of VUR using PPC as a bulking agent. Thus, patients who have undergone EC with PPC must be monitored sonographically for occurrence of OC for at least 60 months after the intervention.

The promise of regenerative medicine in the treatment of urogenital disorders

Polymers and scaffolds are the most significant tools in regenerative medicine. Urogenital disorders are an important group of diseases that greatly affect the patient's life expectancy and quality. Reconstruction of urogenital defects is one of the current challenges in regenerative medicine. Regenerative medicine, as well as tissue engineering, may offer suitable approaches, while the tools needed are appropriate materials and cells. Autologous urothelial cells obtained from biopsy, bone marrow-derived stem cells, adipose stem cells and urine-derived stem cells that expressed mesenchymal cell markers are the cells that mainly used. In addition, two main types of biomaterials mainly exist; synthetic polymers and composite scaffolds that are biodegradable polymers with controllable properties and naturally derived biomaterials such as extracellular matrix components and acellular tissue matrices. In this review, we present and evaluate the most appropriate and suitable scaffolds (naturally derived and synthetic polymers) and cells applied in urogenital reconstruction.

Changing bulking agent may require change in injection volume for endoscopic treatment of vesicoureteral reflux

Introduction:

Various bulking agents were utilized for endoscopic correction of VUR. A study reviewing multi-institutional data showed that the amount of injection material has increased over time with the purpose of improving success rates, which also resulted in costs. We noticed an opposite trend in our center since we started using a new bulking agent. The aim of this study was to evaluate evolution of our practice with different bulking agents.

Patients and Methods:

Records of VUR patients who underwent subureteric injection with polyacrylate polyalcohol copolymer (PPC) and dextronomere hyaluronic acide (DxHA) between 2005 and 2014 were reviewed. Variation of different parameters throughout the study period was evaluated along with the success rate. Success was defined as complete resolution of reflux.

Results:

A total of 260 patients with 384 refluxing units were included. The success rate was higher in PPC group compared to DxHA group. There was no statistically significant difference between years regarding distribution of VUR grade, body weight, patient height, and age in PPC group. Despite significant reduction in injection volume, success rate did not decrease through the years with PPC.

Conclusion:

Different bulking agents may require different injection volumes to achieve the same success rate in endoscopic treatment of vesicoureteral reflux. Habits gained with previous experience using other materials should be revised while using a new agent.

Idiosyncratic reaction after injection of polyacrylate - polyalcohol copolymer

Context:

Polyacrylate-polyalcohol copolymer is a synthetic product, non-biodegradable, with low rate of therapeutic failure and lower incidence of reactions at the site of injection, when compared to biodegradable agents. We report an unprecedent, exuberant and persistent inflammatory reaction following injection of that substance.

Patient:

a 17 years-old patient with vesico-ureteral reflux and complete pyelocaliceal right duplication was submitted to treatment with polyacrylate-polyalcohol copolymer (STING technique). In the seventh day of post-operatory, she presented intense dysuria and hypogastric pain, without laboratory exams alterations; a symptomatic treatment was started. After two months, the symptoms persisted and an ultrasound detected thickening of bladder wall close to the uretero-vesical junction. After that exam, a cystostopic biopsy showed epithelial hyperplasia with increased edema of lamina propria, suggesting an adverse reaction to the polymer. After four months, there was complete remission, but the reflux persisted with the same grade.

Hypothesis:

This is an unprecedent reaction following injection of this copolymer. The presence of characteristics such as absence of infection, temporal relation between treatment and beginning of symptoms, and detection of epithelial hyperplasia at the local of injection reinforce the hypothesis of association of the substance and adverse reaction. In that patient, important complains motivated early investigation of urinary tract, that confirmed those aspects. Maybe if that reaction had occurred in patients with lower capacity of expression (such as in infants) it would be unnoticed.

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 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.

Comparison of results of endoscopic correction of vesicoureteral reflux in children using two bulking substances: Dextranomer/hyaluronic acid copolymer (Deflux) versus polyacrylate-polyalcohol copolymer (Vantris)

BACKGROUND

Endoscopic correction of vesicoureteral reflux (VUR) in children offers minimally invasive management and is widely used as a first-line procedure for all grades of reflux. However, there is debate about which tissue-augmenting substance is the best to use. The aim of this study was to evaluate the efficacy of two bulking substances, Deflux (Dx/HA) and Vantris (PPC), for endoscopic treatment of VUR in children.

METHODS

From 2009 to 2012, 65 children (50 girls and 15 boys) aged 1.45-9.9 years (mean 4.85 ± 2.52) underwent endoscopic correction of VUR using Deflux. VUR was unilateral in 31 patients and bilateral in 34 patients, comprising 108 renal refluxing units (RRUs) grades: II in 52, III in 47, IV in 7, and V in 2. From 2012, 68 children (43 girls and 25 boys) aged 0.6-17.9 years (mean 4.89 ± 3.46) were treated with Vantris. VUR was unilateral in 33 and bilateral in 35 patients, comprising 109 RRUs grades: II in 48, III in 29, IV in 13, and V in 19. Voiding cystourethrogram was done 3 months after procedure.

RESULTS

All patients completed follow-up (summary Table). With Deflux, reflux resolved in almost 93% of RRUs after two procedures (in 63% after first injection), with Vantris, VUR was corrected in the same percentage after one procedure.

DISCUSSION

The success rate with Deflux ranges between 68% and 92% (only 50-70% after single injection). The reported possibility of reflux recurrence after successful Deflux treatment, and the need for repeated injection led to introduction of the new substance Vantris. The results of a multi-centre survey published in 2014 showed that reflux is corrected in more than 90% of cases after single PPC injection. Our results with PPC confirm a high level of reflux resolution.

CONCLUSIONS

Our data show that Vantris injection is a safe and effective procedure for treating all grades of VUR with good clinical outcome, and provides a higher and almost complete level of reflux resolution after first injection compared with Deflux.

The outcomes of two different bulking agents (dextranomer hyaluronic acid copolymer and polyacrylate-polyalcohol copolymer) in the treatment of primary vesico-ureteral reflux

PURPOSE

Subureteral injection of bulking agents in the endoscopic treatment of vesicoureteral reflux is widely accepted therapy with high success rates. Although the grade of vesicoureteric reflux and experience of surgeon is the mainstay of this success, the characteristics of augmenting substances may have an effect particularly in the long term. In this retrospective study, we aimed to evaluate the clinical outcomes of the endoscopic treatment of vesicoureteric reflux (VUR) with two different bulking agents: Dextranomer/hyaluronic acid copolymer (Dx/HA) and Polyacrylate polyalcohol copolymer (PPC).

MATERIALS AND METHODS

A total 80 patients (49 girls and 31 boys) aged 1-12 years (mean age 5.3 years) underwent endoscopic subureteral injection for correction of VUR last six years. The patients were assigned to two groups: subureteral injections of Dx/HA (45 patients and 57 ureters) and PPC (35 patients and 45 ureters). VUR was grade II in 27 ureters, grade III in 35, grade IV in 22 and grade V in 18 ureters.

RESULTS

VUR was resolved in 38 (66.6%) of 57 ureters and this equates to VUR correction in 33 (73.3%) of the 45 patients in Dx/HA group. In PPC group, overall success rate was 88.8% (of 40 in 45 ureters). Thus, Thus, this equates to VUR correction in 31 (88.5%) of the 35 patients.

CONCLUSIONS

Our short term data show that two different bulking agent injections provide a high level of reflux resolution and this study revealed that success rate of PPC was significantly higher than Dx/HA with less material.