Is Percentage Improvement in Anteroposterior Pelvic Diameter a Valuable Marker for Successful Drainage Postpyeloplasty in Isolated Pediatric Pelvi-ureteric Junction Obstruction.

Abstract

Pelvic-ureteric junction obstruction (PUJO) causes urine stasis in the renal pelvis and progressive kidney damage. Postpyeloplasty improvement of renal function and urinary drainage is assessed by diuretic isotope renogram and ultrasonography. Renograms are expensive and have radiation exposure. This study explores whether ultrasound parameters such as percentage improvement in anteroposterior pelvic diameter (PI-APD) is a valuable markers for successful pediatric pyeloplasties. The aim of this study was to identify patients who would benefit from ultrasound monitoring of PI-APD alone instead of diuretic isotope renal scan for postoperative follow-up of pyeloplasty. This was a retrospective descriptive study. We analyzed 127 pediatric pyeloplasties performed and under follow-up between June 2016 and May 2021. We recorded the postoperative ultrasound and isotope renogram parameters. PI-APD (preoperative AP diameter - postoperative AP diameter)/preoperative AP diameter × 100) was compared with improvement in renogram parameters (differential renal function, Tmax, curve pattern, and retention) to look for a correlation between them. SPSS version 20.5, Chi-square and paired t-test were used for statistical analysis. About 73.2% of patients were males, with most cases detected antenatally (76.4%). The majority was left-sided PUJO (67.7%). The mean age at surgery was 30.8 months. We identified a statistically significant correlation between the ultrasound parameter PI-APD and the renogram parameter Tmax. There is no significant correlation between PI-APD and other renogram parameters. In patients whose ultrasound parameter PI-APD is >40% and renal parenchymal thickness has increased, isotope renograms can be avoided for follow-up of postpyeloplasty patients.