Postnatal unilateral pelviureteral junction obstruction: impact of pyeloplasty and conservative management on renal function.

OBJECTIVES: To study the effect of pyeloplasty and conservative management on renal function in children with pelviureteral junction obstruction.

METHODS: This prospective study included 65 children postnatally diagnosed with unilateral pelviureteral junction obstruction. On the basis of the patients' symptoms and technetium-99m diethylenetriamine pentaacetic acid renal isotope scan findings, symptomatic patients or those with split function of the corresponding kidney of 40% or less were assigned to group 1 (n = 35) and underwent pyeloplasty. Asymptomatic patients with split function greater than 40% (group 2, n = 30) were treated conservatively. Patients who showed deterioration of renal function underwent pyeloplasty. The effect of both lines of treatment on renal function was evaluated.

RESULTS: After pyeloplasty, group 1 had improvement in the glomerular filtration rate (GFR) in 30 (85.7%), stabilization in 2 (5.7%), and deterioration in 3 (8.6%) patients. In group 1, the comparison between the mean value of the baseline GFR (17.1 +/- 7.7 mL/min) and its mean value at follow-up (28 +/- 6.3 mL/min) showed an increase of statistical significance (P <0.01). In the group 2 patients, conservative treatment resulted in improvement in the GFR in 12 (40%), stabilization in 3 (10%), and deterioration in 15 (50%) patients. In group 2, no significant difference was found between the mean baseline GFR (29.8 +/- 9.8 mL/min) and its mean value at follow-up (31.2 +/- 5.6 mL/min).

CONCLUSIONS: In patients with postnatal pelviureteral junction obstruction, early pyeloplasty is recommended if the corresponding GFR is 40% or less. Conservative management in patients with better function resulted in deterioration of renal function in 50%. Should this policy of treatment be chosen, meticulous follow-up is mandatory.