Factors affecting the success of endoscopic treatment of vesicoureteral reflux and comparison of two dextranomer based bulking agents: does bulking substance matter?

INTRODUCTION

Among the interventional treatment modalities for vesicoureteral reflux (VUR), endoscopic subureteric injection seems to be the least invasive method with acceptable outcomes when applied in appropriate patients.

OBJECTIVE

The aim of the presented study is to investigate the parameters which may affect the outcomes of endoscopic injection and to compare the efficacy of two different bulking agents both composed of dextranomer-hyaluronic acid copolymer.

STUDY DESIGN

The data of patients who underwent endoscopic VUR treatment between 2003 and 2012 were retrospectively reviewed. Patients with history of previous open antireflux surgery, more than one failed endoscopic treatment for reflux, VUR caused by posterior urethral valve, duplex system and overt spinal dysraphism were excluded. Surgical technique was the classical STING method. One of the two dextranomer-hyaluronic acid copolymer agents was used (Deflux in 109 and Dexell in 131 patients). Both agents were composed of similar amounts of hyaluronic acid gel (15 mg in Deflux versus 17 mg in Dexell) but different sized dextranomer microspheres (80-250 μm in Deflux and 80-120 μm in Dexell). During the follow-up, ultrasonography was performed with 3-month interval, antibiotic prophylaxis was continued until the control voiding cystourethrography (VCUG) was taken. Patient based success was defined as the disappearance of reflux on control VCUG performed 3-6 months after the operation.

RESULTS

Data were available for 240 patients. Mean age and mean postoperative follow-up were 78 ± 41 months and 19 ± 18 months. The overall success rate was 73.2%. Gender, laterality, grade of VUR, presence of voiding dysfunction, renal scar and preoperative breakthrough infection (BTI) were not found to affect the outcome, whereas age younger than 54 months and previous history of failed endoscopic injection were found to negatively affect the outcome both in univariate and multivariate analysis. The postoperative UTI (5 febrile and 43 nonfebrile) rate was 20%. Both univariate and multivariate analysis showed that postoperative UTI was more common in patients with persisting reflux, with preoperative breakthrough infections and in girls. Patient characteristics, treatment outcome and postoperative UTI rate were similar regarding the used bulking agent. No ureteral obstruction was experienced within the follow-up period.

DISCUSSION

Our success rate for second injection is about 60%, which is significantly lower than for the patients who underwent first injection. We could not find any affecting factor for this difference. Contrary to the literature, our success rates were similar in different reflux grades. We can explain this finding that we value the intraoperative orifice configuration more than the grade which can be accepted as a patient selection bias. The lower success rate in children younger than 54 months can be explained by unstabilized bladder dynamics and higher voiding pressures in this age group, who are still in the toilet-training phase. Despite successful endoscopic treatment, UTI might occur. Postoperative UTI was more common in patients with persisting reflux, preoperative BTI and girls. The similar success rates of both bulking agents proved that dextranomer size does not affect the clinical outcome. Limitations of our study can be counted as follows: 1. the data do not include the number of patients in whom conversion to open surgery was decided intraoperatively because of the unfavorable orifice configuration, 2. our data do not include the injected volume records.

CONCLUSION

Endoscopic treatment of VUR has satisfying outcomes in properly selected cases. Younger age (<54 months) and previous history of failed injection history were found to be related to unfavorable results. Postoperative UTI occurs more frequently in patients with persisting reflux, preoperative breakthrough infection history and girls. The choice of one of the dextranomer-based substances does not affect the surgical outcome and postoperative UTI development.