Effective predictors for surgical decision in antenatal hydronephrosis: a prospective multiparameter analysis.

OBJECTIVE: The majority of antenatal hydronephrosis disappears spontaneously. In our study, we have investigated the effective predictors for surgical decision in antenatal hydronephrosis.

MATERIAL AND METHODS: Forty-four patients found to have renal pelvic anteroposterior (AP) diameter more than 10-mm on antenatal ultrasonograpy were followed after birth. The study groups were divided into two groups: follow-up and surgery group. On follow-up, longitudinal diameter of the kidney, parenchymal thickness of the kidney, AP diameter of renal pelvis, AP diameter of middle calyces on ultrasonograpy, and differential renal function, 20th minute clearance, half-life of radionuclide tracer (T1/2), Tmax, Tmax-T1/2, normalised residual activity (NORA) on diuretic renography were evaluated. Ultrasonograpy and diuretic renography measurements were compared in patients whose hydronephrosis resolve or proceeded to surgery.

RESULTS: Forty-four patients were diagnosed as antenatal hydronephrosis, spontaneous resolution occurred in 23 (52%), and surgery was performed in 21 patients (48%). Mean age at operation was 8.5±6.5 months (3-24 months). Mean AP diameter of renal pelvis was 29.5±14.2 mm for surgery group, 13.6±4.2 mm for follow-up group (p<0.001). Univariate analyses showed significance for all ultrasonographic measurements and only the differential renal function by diuretic renography. Multivariate logistic regression analysis showed significance for AP diameter of renal pelvis (odds ratio 1.37; 95% Cl 1.13-1.66), and differential renal function (odds ratio 1.14; 95% Cl 1.01-1.29).

CONCLUSION: AP diameter of renal pelvis and differential renal function were the most effective parameters for surgical decision. These parameters can be used for appropriate management of antenatal hydronephrosis.