Related Experiment Video
Updated: Jan 30, 2026
Real-Time Void Spot Assay
Published on: February 10, 2023
Intrarenal reflux, an overlooked entity - retrospective analysis of 1,166 voiding cysturethrographies in children
Karl O Schneider1, Katarina Lindemeyer2, Birgit Kammer3
1Department of Pediatric Radiology, Klinikum der Universität München, Lindwurmstr. 4, 80337, Munich, Germany. Karl.Schneider@med.uni-muenchen.de.
Insights
Intrarenal reflux occurs in 11% of patients with vesico-uretero-renal reflux, primarily in younger children and with higher reflux grades. This finding is crucial for understanding renal scarring risk.
Area of Science:
- Pediatric Nephrology
- Urology
- Radiology
Background:
- Intrarenal reflux is a known risk factor for renal scarring and hypertension.
- Detection of intrarenal reflux via fluoroscopy is equipment and technique dependent.
Purpose of the Study:
- To determine the prevalence of intrarenal reflux.
- To investigate associations between intrarenal reflux and patient age, gender, vesico-uretero-renal reflux grade, and affected renal segments.
Main Methods:
- Retrospective analysis of 1,166 voiding cysturethrographies in patients aged 1 day to 19 years.
- Standardized digital pulsed fluoroscopy technique used to detect vesico-uretero-renal reflux.
- Radiographs with reflux were assessed for intrarenal reflux occurrence, timing, and grade.
Main Results:
- Intrarenal reflux was identified in 11% (41/373) of patients with vesico-uretero-renal reflux.
- Affected patients were exclusively under 9 years old (mean age 1.6 years).
- Intrarenal reflux was most common in grade IV vesico-uretero-renal reflux (59.6%) and independent of gender.
Conclusions:
- Intrarenal reflux affects 11% of patients with vesico-uretero-renal reflux.
- It is predominantly seen in younger children (under 4 years) and with higher reflux grades (IV).
- Findings aid in risk stratification for renal damage.
Background:
The significance of intrarenal reflux as a risk factor for renal scarring and hypertension has been discussed. Fluoroscopic detection of intrarenal reflux depends on the equipment, the training of the radiologists and the timing of spot film acquisition.
Objective:
To evaluate the prevalence of intrarenal reflux and its association with age, gender, grade of vesico-uretero-renal reflux and the renal segments affected.
Materials And Methods:
We retrospectively analysed 1,166 voiding cysturethrographies. Patients' ages ranged from 1 day old to 19 years old. Vesico-uretero-renal reflux was detected in 209 female and 164 male patients using a standardised technique with digital pulsed fluoroscopy. The point in time and grade of reflux were documented with spot films. All radiographs showing reflux were assessed for the occurrence of intrarenal reflux.
Results:
Intrarenal reflux was detected in 41 of 373 (11%) patients with vesico-uretero-renal reflux. Unilateral intrarenal reflux was found in 30 patients and bilateral in 11. The left kidney was more frequently affected than the right (31 versus 21). Only patients younger than 9 years of age were affected (mean age: 1.6 years, median: 0.8 years). Intrarenal reflux was independent of gender and was most frequently observed in grade IV reflux (59.6%) and less often in grade V (23.1%) and grade III (17.3%).
Conclusion:
Intrarenal reflux in this study was detected in 11% of patients with vesico-uretero-renal reflux, predominantly with reflux grade IV and in patients younger than 4 years old.
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