Renal function may not be restored when using decreasing differential function as the criterion for surgery in...

To evaluate the use of decreasing differential function (DF) as an indication for surgery in children with congenital hydronephrosis followed according to a flow chart with repeated renography and ultrasonography.

The hospital records of consecutive children (0-12 years old) who underwent an Anderson-Hynes pyeloplasty between 1993 and 2000 were reviewed. Follow-up was recommended according to a flow chart, with isotope renography and ultrasonography at 1, 3 and 6 months, and at 1 (2), 3 and 5 years of age. The diagnosis and follow-up were often at the referring hospital. The criteria for surgery included a decrease in renographic DF of > 10% of DF, and a DF of < 42%, breakthrough pyelonephritis despite antibiotic prophylaxis, pain or an anterior-posterior pelvic diameter of > 50 mm.

Fifty-two children with unilateral hydronephrosis were included; eight had surgery because of decreasing DF of the hydronephrotic kidney. Seven children had a prenatal diagnosis. Only one of these eight children was managed according to the recommended procedures for follow-up. In two and possibly three children there was significant irreversible kidney damage since the initial renography before surgery. In one child the initial renography was at 15 months and the DF was < 10%. There was a functional improvement after surgery in three children.

Few children undergo surgery for decreasing DF of the hydronephrotic kidney in this study. Failure to adhere to the follow-up schedule was common; this may jeopardize kidney function when using decreasing DF as a criterion for surgery. Therefore, not complying (by medical staff or the patient) with the follow-up should be considered when using expectant management for asymptomatic hydronephrosis. The serious consequences for renal function of not complying with follow-up can be avoided by surgery if the patient risks renal functional deterioration, by close cooperation with medical staff at referring hospitals, and by close follow-up at an early age with renography and ultrasonography.