A new renal growth parameter for the hydronephrotic kidneys

초록

Introduction and Objectives: Clinical questions to pediatric urologists arise when we observe the hydronephrotic kidneys after operation because we have no definite method to measure the absolute size and change of hydronephrotic kidneys except the relative size such like radio-isotope study. The nomogram of renal length from normal kidneys cannot be used on this kidneys because hydronephrosis elongate the renal length in the center of kidney. The purpose of this study was to determine the normal range of renal representative size for hydronephrotic patients and assess the postoperative growth of hydronephrotic kidneys. Materials and Methods: We reviewed the charts and radiological files(251 Ultrasonography, 223 IVP) of 474 patients(male: 242, female: 232; under 16 years old) with normal kidneys followed at our institution and severance hospital. Patients were excluded from study due to hydronephrosis or hydroureter, solitary kidney, recurrent symptomatic urinary tract infection, vesicoureteral reflux. We designed a new parameter, average parenchymal thickness(APT) of 3 representative parenchymal region(upper, mid, lower) measured by ultrasonography. Results: A renal APT normogram was constructed by plotting patient age against APT, expected means and standard deviations for each age group and fitted by nonlinear regression(95% confidence range) using WinNONLIN program. There was no significant difference between right and left kidneys, between male and female. But the values from IVP was magnified comparing to those from ultrasonography. Conclusions: APT represent not the relative change of hydronephrotic kidney compared to the other normal one, but the absolute state and change of hydronephrotic kidney itself in postoperative period. This nomogram of APT will be of good use in routine practice for pediatric urology performing the operation in hydronephrosis. It is hoped that more practical trials using this parameter will be developed sooner or later.