# Does unilateral reflux have a protective effect in posterior urethral valve patients?

## TL;DR

This study examines whether unilateral reflux helps protect kidney function in boys with posterior urethral valves.

## Contribution

The study provides new evidence that unilateral reflux may offer a protective effect on renal outcomes in PUV patients.

## Key findings

- Unilateral VUR patients had similar renal outcomes to those without VUR.
- Bilateral VUR was associated with worse renal outcomes compared to unilateral or no VUR.
- Nadir creatinine levels were identified as independent risk factors for abnormal renal function.

## Abstract

To evaluate the protective role of unilateral reflux on renal function in PUV patients. Various protective mechanisms have been proposed in patients with posterior urethral valves (PUV). The role of unilateral reflux as a protective factor is debated.

A retrospective analysis was conducted on 92 male PUV patients treated between January 1986 and July 2023. Unilateral VUR patients and ipsilateral renal function < 15% were classified as having valve unilateral reflux dysplasia (VURD) syndrome. Data from 92 patients were analyzed using scintigraphy. Renal function was considered abnormal if serum creatinine levels exceeded age-specific norms. Univariate and multivariate analyses assessed various parameters.

The median age at primary surgery was 5 months, with a median follow-up of 35 months. Bilateral VUR patients (55.2%, 16/29) had worse renal outcomes than those with no VUR (25%, 8/32) or unilateral VUR (19.3%, 6/31; (p = 0.016, p = 0.004, respectively). Thirteen of 31 patients with unilateral VUR had VURD. Abnormal renal function distribution was similar between unilateral VUR patients, regardless of VURD status. Nadir creatinine value were independent risk factors for abnormal renal function.

Although some studies suggest unilateral reflux protects the contralateral kidney, others indicate worse outcomes due to dysplasia. Our findings show that renal outcomes in unilateral VUR patients are comparable with those without VUR, implying a protective effect independent of ipsilateral dysplasia. Patients with unilateral VUR exhibit similar outcomes to those without VUR. Nephrectomy should be cautiously considered due to potential protective effects.