Obstruction of the Ureteropelvic Junction in Children: Functional Evaluation of the Obstructed Kidney Postoperatively Using the 99mTc-DMSA Renal Scan

Hwang, Yun Joong; Woo, Young Nam

Abstract

Ten children were selected out of 21 cases diagnosed as ureteropelvic junction obstruction between March, 1989 and March, 1992. The children were evaluated quantitatively using the renal cortical labeling agent, 99m technetium dimercaptosuccinic acid (Tc-DMSA), before and following pyeloplasty. The preoperative residual renal function and the extent of functional recovery were investigated. The children ranged from 15 months to 13 years old (average 6.8 years) and consisted of 8 boys and 2 girls. The obstruction was on the left in 7 cases and the right in 3. Symptoms on admission included pain in 5 cases, abdominal mass in 3 cases, and fever and chill in 2. The subjects divided into two groups. The first group consisted of children who did not have complications or other coexisting diseases, while the second consisted of who had pyonephrosis or vesicoureteral reflux. All patients underwent dismembered pyeloplasty and the results were satisfactory in all. 1. The preoperative differential renal function by Tc-DMSA renal scintigraphy ranged from 0.5% to 46.0% (mean 19.1%) and increased to 3.5% to 46.9% (mean 28.8%) postoperatively. 2. In five of the seven cases with uncomplicated ureteropelvic junction obstruction, differential renal function increased more than 1096 following pyeloplasty. In the two other cases which showed preserved renal function of up to 4096 preoperatively, noticeable changes not observed. 3. In the three cases with complicated ureteropelvic junction obstruction, (two cases associated with pyonephrosis and one case with vesicoureteral reflux) only slight increased differential renal function. In conclusion, we suggest that severely obstructed kidneys in infants and children spare nephrectomy and encourage pyeloplasty, even in cases of non-visualization on excretory urography in hopes of improving relative renal function.