Renal Calyx to Parenchymal Ratio versus Anteroposterior Pelvic Diameter in Predicting Outcome of Pyeloplasty for Uretero-Pelvic Junction Obstruction

Abstract

Background: After surgical correction of Ureteropelvic junction obstruction (UPJO) follow up is commonly performed by anteroposterior diameter (APD) of renal calyx in ultrasonogram and by GFR and deferential renal function (DRF) renogram. The aim of the study was to find out the accuracy of renal calyx to parenchyma ratio (CPR) and APD to predict outcome after pyeloplasty. Methods: This prospective comparative study was conducted on children age 0 to 12 years with unilateral UPJO. APD and CPR in USG and Glomerular Filtration Rate (GFR), Differential Renal Function (DRF) with graph in renogram was selected as the predictor of surgical outcome of pyeloplasty. All the data were collection in 3 occasions: preoperative, at 3rd month and at 6th month after surgery. Results: Among 20 patients, mean age was 4.72 (± 2.74) years. Difference between preoperative and postoperative 6th month of CPR (ΔCPR) and percentage change of difference between preoperative and postoperative 6th month of CPR(%ΔCPR) strongly predicted successful pyeloplasty with a higher sensitivity (85.7% and 21.4%) respectively. In contrast difference between preoperative and postoperative 6th month of APD (ΔAPD) and percentage change of difference between preoperative and postoperative 6th month of APD (%ΔAPD) predict successful pyeloplasty with a sensitivity of (42.9% vs 78.6%) and difference between preoperative and postoperative 6th month of DRF (Δ DRF) and percentage change of difference between preoperative and postoperative 6th month of DRF (%Δ DRF) predict successful pyeloplasty with a sensitivity of (57.1% vs 57.1%). Conclusion: CPR can predict the surgical outcome of pyloplasty like APD, DRF and GFR; and should be assesses during follow up. Journal of Paediatric Surgeons of Bangladesh (2026) Vol. 17 (2): 4-10