Postoperative Management of Infants with UPJO: A Retrospective Cohort Study of PICU Transfer, Complications, and Length of Stay

Background: Postoperative management of infants with ureteropelvic junction obstruction (UPJO) is challenging due to their inability to express symptoms and risk of rapid deterioration. This study aimed to describe our institutional experience with a combined urology–PICU protocol and to explore complication patterns, length of stay (LOS), and costs in this population. Methods: Data from 84 consecutive infants (≤12 months) who underwent LP for UPJOrelated hydronephrosis at our institution from December 2020 to December 2025 were retrospectively analyzed. Patients were divided into Group A (PICU transfer, n=62) and Group B (general ward care, n=22). Surgical outcomes, complications graded by the ClavienDindo classification, LOS, and hospitalization costs were compared. Propensity score matching (PSM) was performed as an exploratory analysis to balance baseline differences. Univariable and multivariable logistic regression analyses were performed to identify factors associated with PICU transfer and adverse outcomes, defined as Clavien-Dindo grade ≥III. All analyses explicitly acknowledge confounding by indication and baseline noncomparability. Results: In the full cohort, Group A was significantly younger at surgery (mean 4.77 vs. 9.23 months, P<0.001) and incurred higher hospitalization costs (median 37,080.50 vs. 31,072.26 CNY, P<0.001); operative time, blood loss, and LOS were similar. The proportion of patients with Clavien-Dindo grade ≥II complications was lower in Group A (74.2% vs. 100%, P=0.008), as was the incidence of any respiratory complication (67.7% vs. 95.5%, P=0.01), driven primarily by a marked reduction in bronchitis (17.7% vs. 50.0%, P=0.003). Four patients (18.2%) in Group B required unplanned PICU transfer due to postoperative deterioration. In the PSM cohort (12 pairs), Group A had a lower proportion of Clavien-Dindo grade ≥II complications (58.3% vs. 100%, P=0.012) and a lower incidence of bronchitis (0% vs. 41.7%, P=0.012), but the small sample renders these estimates unstable. In multivariable analysis, younger age (OR, 0.61; 95% CI, 0.46–0.75; P<0.001) and operative side (OR, 0.15; 95% CI, 0.03–0.60; P=0.011) were independently associated with PICU transfer. No evaluated factor was independently associated with adverse outcomes (Clavien-Dindo grade ≥III). A positive correlation existed between Clavien grade and the number of concurrent complication types; complications ≥ Grade III significantly prolonged LOS. Conclusions: Infants after LP face a substantial burden of nonsurgical complications. In this retrospective cohort, PICU transfer was associated with younger age and operative side after adjustment, while no independent association was identified between the evaluated factors and Clavien-Dindo grade ≥III adverse outcomes. Because of substantial confounding by indication, the study is hypothesis-generating and cannot establish a causal effect of PICU care. Prospective multicenter studies are needed to validate objective triage criteria and assess cost-effectiveness.