Elsevier

Journal of Pediatric Urology

Volume 16, Issue 2, April 2020, Pages 191.e1-191.e6
Journal of Pediatric Urology

The fate of implant after endoscopic injection of dextranomer/hyaluronic acid in vesicoureteral reflux: time to partial reabsorption and stabilization

https://doi.org/10.1016/j.jpurol.2019.12.010Get rights and content

Summary

Background/introduction

Vesicoureteral reflux (VUR) potentially leads to renal damage, scarring, and eventually end-stage renal disease. Endoscopic treatment is well tolerated in children, it has reduced costs, and it effectively prevents urinary tract infections (UTIs), while avoiding long term antibiotics use.

Objective

With the aim to investigate the time needed to reach the stabilization of the dextranomer/hyaluronic acid (Dx/HA) implants and to identify cut-off heights to ensure the success of the procedure, the authors analyzed ultrasonographic (US) intra-operative appearance of the mounds following endoscopic treatment for VUR and repeated the measurements during serial postoperative evaluations. The final clinical goal would be to obtain an alternative parameter that might reduce the need for postoperative voiding cystourethrogram (VCUG).

Study design

The authors selected all children treated for moderate-high grade VUR with renal scarring or repeated UTI under antibiotic prophylaxis and followed with regular time points for at least 1 year (time points 1, 3, 6, and 9 months). Endoscopic injection performed with double-HIT/STING technique was combined with US to determine the intra-operative mound height and to calculate reabsorption rate. Mound height was measured as the maximal vertical diameter of the mound visualized at the ureteral orifice. Based on postoperative VCUG findings, patients were divided in group A (success of the endoscopic treatment) and group B (persistence of reflux).

Results

Thirty patients aged 1–7 years, counting for 47 ureters, completed the protocol and were included in the analysis. Mounds height had a significant difference between A and B at all time points (P < 0.005). However, height did not differ between 6 and 9 months in both groups. Percentage of reduction in A was significant from 1 to 6 months (P < 0.005) but not onward, while in B, it was never significant. Ultimately, both groups had a comparable trend of reabsorption, with a complete stabilization achieved in 6 months and an overall reduction of approximately 22%.

Discussion and conclusion

Following the endoscopic injection of Dx/HA, US mounds height was found to strongly correlate with VCUG, both intra-operatively and for months following the procedure. Compared with the available literature, the authors first report a fixed reabsorption rate, consistent with the results in animal models and a timeframe to achieve stabilization. The possibility to measure those parameters with US renders this approach useful in the clinical setting, and it justifies the reduced use of VCUG in the follow-up of endoscopic injection for VUR.

Summary Table.

Time pointsMean ± SD successMean ± SD
Failure
P-value
Height at T010.60 ± 1.438.62 ± 1.37P < 0.0005
Height at T19.40 ± 1.277.60 ± 1.20P < 0.0005
Height at T38.70 ± 1.136.90 ± 1.13P < 0.0005
Height at T68.40 ± 1.086.73 ± 1.14P < 0.0005
Height at T98.28 ± 1.066.62 ± 1.11P < 0.0005

Introduction

Vesicoureteral reflux (VUR) is a common urological disease, which affects 1% of the pediatric population, and it potentially leads to renal damage, scars, and eventually, end-stage renal disease [1]. Recently, shared goals of treatment are the prevention of urinary tract infections (UTIs), the avoidance of long-term antibiotics use and the reduction of radiation exposure. Endoscopic treatment is well tolerated in children, it has reduced costs compared with other treatment modalities, and it effectively achieves the first two goals [2]. These reasons warrant endoscopic treatment as an emerging treatment of choice for VUR. Despite guidelines recommendations, which still suggest postoperative voiding cystourethrograms (VCUG), many authors nowadays deem VCUG superfluous in favor of an adequate ultrasonographic (US) follow-up [3]. However, few studies exist on implant changes at follow-up and even fewer on the US appearance.

In the present study, the authors evaluated US appearance of mounds in children undergone endoscopic injection of dextranomer/hyaluronic acid (Dx/HA) for VUR treatment. The final aim was the identification of a new parameter, which could be useful to determine the success rate both intra-operatively and during the follow-up to reduce the need for VCUG. Mound heights were recorded during the postoperative visits and compared with intra-operative measures to calculate reabsorption rate. Secondary endpoints were considered the evaluation of the time needed to reach stabilization of implants and cut-off heights to ensure the success of the procedure.

Section snippets

Materials and methods

The authors considered all consecutive patients referred to the authors Urologic Outpatient Clinic between April 2015 and March 2016 for primary VUR. The study included children with recurrent febrile upper UTI and either primary reflux grade 3 to 5 confirmed by pre-operative VCUG or grade 2 in presence of contralateral high-grade reflux; eligible patients under 1 years of age were initially managed conservatively and thereafter re-evaluated. Exclusion criteria were grade 1 VUR, presence of

Results

A total of 30 consecutive patients, 47 ureters, matching the inclusion criteria, underwent Dx/HA injection with IO-US monitoring and attended the planned postoperative assessment. Five patients were excluded from the analysis as they did not attend all the postoperative assessment (Table 1). Of the 30 patients, 16 were females. VUR was unilateral in 13 (27.7%) and bilateral in 34 (72.3%) children. The average age at surgery was 37 ± 23 months, ranging from 14 months to 7 years. Of the 47 renal

Discussion

Management options available for pediatric VUR include watchful waiting, medical treatment with continuous antibiotics prophylaxis and various surgical alternatives [6]. Among those, endoscopic treatment is widely considered an optimal choice compared with ureteroneocystostomy in terms of reduced morbidity (less pain, no scars), shorter hospitalization, reduced costs, and increased patients’ preference.

Owing to inadequate intra-operative indicators and variable success rate, international

Conclusions

The present study demonstrates a strong correlation between mound height and result after endoscopic injection of Dx/HA in children intra-operatively and lasting for months. The authors could furthermore report a total reabsorption of 21–23% of implants and a stabilization of the mound around 6 months after surgery. These results highlight how mound height measured by US could overcome the need for routine VCUG following endoscopic injection for non-complicated VUR.

Ethical approval

The Local Ethics Committee approved the study protocol.

Funding

None declared.

Competing interest

None declared.

References (20)

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