Hypothesis / aims of study
Pyeloplasty for ureteropelvic junction obstruction (UPJO) in pediatrics has traditionally been selected for cases of impaired renal drainage or renal function (RF) deterioration. However, there is a risk of possibly irreversible renal damage if RF deterioration occurs before pyeloplasty. Therefore, we evaluated the surgical outcomes of pyeloplasty for UPJO in well-functioning renal units with more than 40% split renal function (SRF).
Study design, materials and methods
In a retrospective study, pediatric patients with unilateral UPJO who underwent open Anderson-Hynes pyeloplasy were included. Patients with solitary kidneys, bilateral UPJO or associated anomalies were excluded. All patients were divided in 2 groups according to preoperative SRF; group 1 (SRF >40%) and group 2 (SRF ≤40%). Renal ultrasonography and renographic images were reviewed to evaluate preoperative baseline characteristics and analyze postoperative anatomical and functional outcomes at 6 and 12 months. Antero-posterior diameter (APD), parenchymal thickness (PT), degree of hydronephrosis (HN) as defined by Society for Fetal Urology (SFU) grading system and SRF were measured. A decline of SRF by more than 5% was considered to be deterioration.
Results
A total of 103 patients were included in the study; 45 patients (44%) had SRF >40%, while 58 patients (56%) had SRF ≤40%. Their mean ages were 4.72 ± 0.15 years. At baseline, both groups had comparable APD, PT and SFU grading of HN (Table 1). The group of SRF >40% showed lower degrees of HN by SFU grading (1.91 ± 1.06 vs. 2.46 ± 0.96, p =0.04) and higher SRF (38.49 ± 13.1 vs. 22.59 ± 13.93, p =0.03) at 6-month follow up and less APD (1.47 ± 0.71 vs. 2.41 ± 1.08, p =0.01) at 12-month follow up relative to the other group. However, both groups did not develop significant change of preoperative SRF after 12 months (Table 1).
Interpretation of results
In our study, 103 pediatric patients with unilateral UPJO were divided into 2 groups according to their SRF, either >40% or ≤40%. Both groups had comparable APD, PT and SFU grading of HN. The group of SFR >40% (group 1) significantly showed lower degrees of HN by SFU grading and higher SRF at 6-month follow up and less APD at 12-month follow up relative to group 2. On the other hand, both groups did not develop significant change of preoperative SFR after 12 months of follow up.