0-6 months versus 6-12 months laparoscopic pyeloplasty in infants: impact on short-term renal ultrasonographic parameters.

OBJECTIVE

To compare postoperative recovery outcomes between infants undergoing laparoscopic pyeloplasty (LP) for unilateral ureteropelvic junction obstruction (UPJO) at 0-6 months versus 6-12 months of age, and to identify whether surgical timing differentially affects longitudinal trajectories of renal ultrasound parameters.

METHODS

This retrospective cohort study included 58 infants with unilateral UPJO who underwent laparoscopic dismembered pyeloplasty between March 2021 and February 2026. Patients were stratified into 0-6 months (n = 34) and 6-12 months (n = 24) groups. Linear mixed-effects models with random intercepts for patient were fitted to analyze longitudinal recovery trajectories of renal ultrasound parameters (anterior-posterior pelvic diameter [APD], hydronephrosis-to-parenchymal area ratio [HPAR], parenchymal thickness [PT], and minimal parenchymal thickness [MPT]), adjusting for baseline value and surgical indications.

RESULTS

The 0-6 months group presented with more severe preoperative hydronephrosis (APD: 33.0 vs. 24.5 mm, P = 0.002; HPAR: 1.11 vs. 0.75, P = 0.009; MPT: 2.38 vs. 3.00 mm, P = 0.015). Both groups showed postoperative improvements in all parameters. Percentage improvement in MPT was greater in the 0-6 months group (1.74 ± 1.40 vs. 0.96 ± 0.77, P = 0.008). Mixed-effects models revealed that only MPT demonstrated a significantly steeper recovery slope in the 0-6 months group (interaction: β = - 0.0015, SE = 0.0006, P = 0.012), whereas APD, HPAR, and PT showed comparable slopes between groups.

CONCLUSION

LP performed at 0-6 months was associated with superior MPT recovery dynamics compared with surgery at 6-12 months, suggesting that earlier intervention may be associated with more favorable MPT recovery dynamics in UPJO.