STING versus HIT technique of endoscopic treatment for vesicoureteral reflux: A systematic review and meta-analysis

Aim: Our study aimed to compare the efficacy of two endoscopic techniques used for the correction of vesicoureteral reflux (VUR): subureteral transurethral injection (STING) and hydrodistension implantation technique (HIT).

Methods: A systematic review was conducted using MEDLINE, Google scholar, and Cochrane databases from 1984 to 2015. Meta-analysis of the selected studies was performed to compare the extent of reflux resolution following both techniques.

Results: Six observational studies met the inclusion criteria for content. These comprised 632 ureters treated by STING and 895 ureters treated by HIT procedure. All included studies utilized dextranomer/hyaluronic acid (Deflux) as the bulking agent. The overall resolution of VUR was significantly higher in HIT (82.5%) compared to STING (71.4%) [pooled odds ratio (OR)=0.54; 95% confidence interval (CI) 0.42-0.69; P<0.0001; I²=8%]. A subgroup analysis showed that HIT had better outcomes than STING for both lower grade (I-III) [OR=0.43; 95% CI 0.23-0.82; P=0.01; I²=0%] and high-grade VUR (IV-V) [OR=0.43; 95% CI 0.20-0.91; P=0.03; I²=0%]. However, there was no statistical difference in the requirement of additional injections between STING and HIT groups.

Conclusion: HIT is superior to STING technique for resolution of VUR after Deflux injection. However, more randomized trials with longer follow-up are necessary to demonstrate the benefit of HIT compared to STING procedure.

Level of evidence: Retrospective comparative studies - level III.