Long term outcomes following pyeloplasty for unilateral pelviureteric junction obstruction in paediatric patients

Background: Pelviureteric junction obstruction (PUJO) is the most common cause of pediatric hydronephrosis. The gold standard treatment for PUJO is Anderson hynes (AH) dismembered pyeloplasty. The parameters to assess the post-operative outcomes of pyeloplasty include reduction in the AP diameter of the pelvis and increase in parenchymal thickness. The aim of the study was to find out the long-term outcomes following pyeloplasty for Ureteropelvic junction obstruction (UPJO) in paediatric patients.Methods: A prospective study was done from September, 2014 to January, 2019. All children above the age of 2 months who presented with unilateral PUJO were included in the study. All patients underwent ultrasound of the kidneys and diuretic renogram. All patients underwent AH dismembered pyeloplasty. Success was defined as both symptomatic relief and radiographic resolution of obstruction at the last follow-up visit.Results: 60 patients with unilateral intrinsic PUJO were included in this study. Post-operatively split renal function (SRF) improved in 42 patients, remained stable in 13, and deteriorated in 5 cases. Post-operative renal drainage improved in 40 patients, remained stable in 15 and deteriorated in 5. The degree of hydronephrosis deteriorated in 5 cases but improved or was preserved in 55 cases. The renal parenchyma deteriorated in 7 cases. Overall success rate of AH dismembered pyeloplasty was 92%.Conclusions: Dismembered pyeloplasty is a safe and effective treatment of PUJO in the pediatric population. Majority of the patients had an improved split renal function, renal drainage, cortical thickness, and decreased degree of hydronephrosis.

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

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.

Renal function estimation done by contrast enhanced computed tomography volume percentage: a better cost-effective alternate for renogram values

Background: For optimal management of obstructive uropathy the function of each renoureteral unit needs to be assessed precisely. Usage of nuclear scan for estimation of split renal function has been standard technique till now. Renal parenchymal volume percentage, which is calculated through multislice CT, used as a surrogate marker of split renal function. The aim of the study was to correlate the renal volume percentage calculated from contrast enhanced computed tomography (CECT) of kidney, ureter and bladder (KUB) with split renal function estimated by the gold standard 99mTc-DTPA (diethylene triamine pentaacetic acid) among obstructive uropathy patients.Methods: Patients who have been diagnosed as chronic unilateral renal obstruction and were requiring 99mTC-DTPA nuclear scan for functional assessment of kidneys were included as our study subjects. A total of 46 patients were taken as our study sample and for all these patients CECT KUB was done and the reports were collected and the renal volume percentage was obtained through those images. Correlation was made between the measurements made by nuclear scan and CECT images in unilateral renal obstruction patients.Results: A positive linear correlation was obtained between DTPA nuclear scan and CECT images in the detection of renal volume/renal function with r value 0.904 (p<0.05) in obstructive renal units and similarly among non-obstructive renal units the r value was 0.889 (p<0.001).Conclusions: Though 99mTc-DTPA renal scan is a safest choice by considering its less radiation exposure and no contrast requirement still cost and its universal availability make us to consider CECT as a better alternative.

Renal functional improvement after pediatric pyeloplasty in kidneys with split renal function less than 20%: a single institute experience

Background Pediatric pyeloplasty in ureteropelvic junction obstruction (UPJO) is indicated in renal impaired drainage or renal function deterioration. The improvement of renal function after pediatric pyeloplasty is still controversial in poorly functioning kidneys. Past studies on poorly functioning kidneys had a variable SRF specification, and these studies often had a limited number of patients so that they did not achieve statistical significance. The study aims to detect the renal functional improvement after pediatric Anderson-Hynes pyeloplasty (AHP) with split renal function (SRF) less than 20% (poor renal function). Results A retrospective study included 46 pediatric patients with unilateral UPJO who underwent open AHP with SRF < 20% on a renal isotope scan from August 2012 to October 2018. Success was defined based on either improvement in symptoms, improvement in drainage on postoperative renography, and/or improvement or stability in SRF on the renal scan done 6 months postoperatively and yearly thereafter. Deterioration of SRF by more than 5% was deemed to be deterioration. An increase in SRF of more than 5% was deemed to be an improvement. A total of 46 patients with a mean age of 32 months with poor renal function on isotope renogram (SRF < 20%) were included. All patients had an obstructive pattern on the preoperative radionuclide scans. The median preoperative SRF was 9.26%. The mean (range) follow-up was 30 months. The success rate was 91.3%. Three patients underwent redo pyeloplasty, whereas a secondary nephrectomy was necessary for one. The remaining (42) patients showed stability or improvement of SRF with no further symptoms. Renal scintigraphy at 6 and 12 months after surgery revealed significantly increased SRF compared to preoperative one. Conclusion Poorly functioning renal unit with SRF < 20% can show functional improvement and recoverability after pediatric pyeloplasty.

Compensation Capacity of The Living-Related Donor’s Remnant Kidney and Recipient’s Transplanted Kidney

Background: Compensatory renal growth following nephrectomy is common. We try to explore the compensatory capacity of the living-related donor’s remnant kidney and recipient’s transplanted kidney in terms of the glomerular filtration rate (GFR) one month after transplantation. Methods: Clinical data of 94 patients who received living-related kidney transplantation in our hospital between June 2007 and December 2017 were reviewed retrospectively. GFR was calculated by 99mTc-DTPA detection. The GFR compensatory capacity of donor’s remnant and donated kidneys in their new milieus after transplantation was compared. The differential value (D-value) of split renal function was defined as postoperative GFR - preoperative ipsilateral GFR. The compensatory percentage (C-percentage) of split renal function was defined as (postoperative GFR - preoperative ipsilateral GFR)/preoperative ipsilateral GFR. Results: The median D-value of the donor’s remnant kidney increased by 20.8 ml/(min·1.73m2)[IQR=8.9-29.6 ml/(min·1.73m2)] with a C-percentage of 46.6% (IQR=17.0%-73.0%). The median D-value of the donated kidney increased by 30.6 ml/(min·1.73m2)[IQR=19.8-42.3 ml/(min·1.73m2)] with a C-percentage of 67.8% (IQR=39.6%-94.7%). Multivariable analysis showed that only split preoperative GFR in the donor was the independent predictor for C-percentage of the split kidney. Conclusions: Renal function could be well preserved and compensated after kidney donation in most donors and recipients in Chinese population. Healthy donors with a good GFR before operation possessed a mighty functional compensation capacity.