Text Box: THE CLINICAL STUDIES OF RENAL HEMODYNAMICS IN CHILDREN WITH HYDRONEPHROSIS
LI Zhaozhu, ZHOU Xianli, SUN Yan, LIU Aiwu, HAN Fuyou, TAO Wenfang.
Department of Pediatric Surgery, the 2 nd Affiliated Hospital of Harbin Medical University, Harbin, China

Objective: To evaluate the renal function and find obstructive hydronephrosis through studies of renal hemodynamics in children with hydronephrosis. 
Methods: We evaluated the intrarenal hemodynamics in 30 patients with unilateral or bilateral hydronephrosis and in 20 children with normal kidney using duplex Doppler Sonography (SIEMENS SONOLINE Elegra Platform, made in Germany). Before operation peak systolic velocity (PS), end diastolic velocity (ED), mean velocity, pulsatility index, and resistive index of the intrarenal arteral flow were examined in the main renal artery in the renal hilum (MRA), segmental renal artery (SRA) and interlobar renal artery (IRA), respectively. We also investigated postoperative intrarenal hemodynamics in 9 cases on Andeson-Hynes procedure at 1 month, 3 month, and 6 month, respectively. IVU, CT, and ECT were performed in some children. 
Results: Anderson-Hynes procedure was performed in 27 cases and nephrectomy in 3 cases. We found that intrarenal blood velocity decreased gradually (p<0.01), and RI was not changed (p>0.05) among MRA, SRA, and IRA in normal renal units. In the patients with hydronephrosis there were significant differences in intrarenal hemodynamics between the 30 patients and 20 normal children (p<0.05). After operation the results of the intrarenal hemodynamics in 30 patients with hydronephrosis reach normal gradually. PI and RI changed most significance in the first postoperative month. There are negative correlation between the thickness of renal cortex and renal square with hydronephrosis (r= -0.73, p<0.01). 
Conclusions: The mean RI values for kidneys of hydronephrosis and normal kidneys were 0.66±0.11 and 0.54±0.04, respectively. The obstruction may be significant and demands surgical intervention when the RI values reach or more than 0.66±0.11. Higher RI is, more obstruction of hydronephrosis is, less recovery of renal function is. The results can be applied clinically to help justify the indications for surgical intervention and to examine postoperative renal function.
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