1491 Hemi-Nephroureterectomy For Duplex Kidney in Children - The Resulting Effect on Renal Function

Abstract

Abstract Introduction Urinary duplication systems occur in approximately 1% of the population, and may present with recurrent UTIs, incontinence, or be incidentally detected on imaging. DMSA (dimercaptosuccinic acid) imaging is used in these patients to assess split renal function. If found significantly reduced in a single moiety, children may be offered hemi-nephroureterectomy (HNU). We analysed the rate of remnant moiety loss following HNU comparing age and affected moiety. Method All HNUs performed at our paediatric tertiary centre 2005-2019 were analysed. Children <16yrs, with pre– and post-operative DMSA imaging were included. Renal loss was categorised as: significant (≥50% of pre-existing function), non-significant (≥25% pre-existing function), no renal loss (<25%), and complete loss (post-operative remnant moiety function ≤5%). Subgroup analysis was performed using χ² statistic. Results 73 patients were included, mean age 2.1yrs. Median pre-operative function of the affected kidney was 42%. 12 patients (16.4%) had significant renal loss, 13 (17.8%) non-significant loss and 6 (8.2%) had complete renal loss. Children <2yrs had significant and complete renal loss more frequently than those aged ≥2yrs (9/35 and 5/35 vs 3/38 and 1/38 respectively, p = 0.069). Patients with upper moiety HNU (UMHNU) had higher rates of significant and complete renal loss than lower moiety HNU patients (12/53=significant, 6/53=complete vs 0/20 significant/complete, p = <0.05). Conclusions HNU for duplex kidney is associated with high rates of remnant moiety damage, with ¼ of patients experiencing significant or complete renal loss. Subgroup analysis suggests this risk is higher in children <2yrs or UMHNU. HNU should therefore only be reserved for symptomatic patients failing conservative management.