Evaluating pediatric ureteropelvic junction obstruction: Dynamic magnetic resonance urography vs renal scintigraphy 99m-technetium mercaptoacetyltriglycine.

BACKGROUND: Ureteropelvic junction obstruction (UPJO) is a common congenital urinary tract disorder in children. It can be diagnosed as early as in utero due to the presence of hydronephrosis or later in life due to symptomatic occurrence. AIM: To evaluate the discrepancy between dynamic contrast-enhanced magnetic resonance urography (dMRU) and scintigraphy 99m-technetium mercaptoacetyltriglycine (MAG-3) for the functional evaluation of UPJO. METHODS: Between 2016 and 2020, 126 patients with UPJO underwent surgery at Robert Debré Hospital. Of these, 83 received a prenatal diagnosis, and 43 were diagnosed during childhood. Four of the 126 patients underwent surgery based on the clinical situation and postnatal ultrasound findings without undergoing functional imaging evaluation. Split renal function was evaluated preoperatively using scintigraphy MAG-3 (n = 28), dMRU (n = 53), or both (n = 40). In this study, we included patients who underwent surgery for UPJO and scintigraphy MAG-3 + dMRU but excluded those who underwent only scintigraphy MAG-3 or dMRU. The patients were divided into groups A (< 10% discrepancy) and B (> 10% discrepancy). We examined the discrepancy in split renal function between the two modalities and investigated the possible risk factors. RESULTS: The split renal function between the two kidneys was compared in 40 patients (28 boys and 12 girls) using scintigraphy MAG-3 and dMRU. Differential renal function, as determined using both modalities, showed a difference of < 10% in 31 children and > 10% in 9 children. Calculation of the relative renal function using dMRU revealed an excellent correlation coefficient with renal scintigraphy MAG-3 for both kidneys. CONCLUSION: Our findings demonstrated that dMRU is equivalent to scintigraphy MAG-3 for evaluating split renal function in patients with UPJO.

Ultrasonographic stabilization of hydronephrosis after pyeloplasty: Key determinant of postoperative follow-up?

INTRODUCTION: Although more than 1500 pediatric pyeloplasties are performed in the United States per year, there is a lack of consensus on the adequate imaging modality and timing of follow-up after surgery. OBJECTIVE: The aim of this study is to evaluate if ultrasonographic stabilization in the grade of hydronephrosis after pyeloplasty is an adequate parameter to define the optimal length of follow-up after surgery and to detect failed procedures. Secondarily, we want to analyze clinical variables that could impact ultrasonographic stabilization. STUDY DESIGN: This is a retrospective chart review of patients who underwent pyeloplasty between 2012 and 2020. Patients were included if they were ≤21 years-old at the time of surgery, had pre and postoperative renal-ultrasounds, had ≥3 months of postoperative follow-up, and had met the criteria for ultrasonographic stabilization after surgery. Ultrasonographic stabilization was defined as 2 consecutive ultrasounds after pyeloplasty, a minimum of 1-month apart, with the same degree of hydronephrosis according to the Society for Fetal Urology (SFU) grading system. Data concerning clinical, surgical, and postoperative variables were collected. RESULTS: A total of 143 pyeloplasties met the inclusion criteria. Median age at surgery was 10.5 months with a median post-operative follow-up time of 29 months. Ultrasonographic stabilization was achieved in a mean time of 14.5 months post-operatively. Compared to the preoperative US SFU grade, at ultrasonographic stabilization 127 (88.9%) patients had an improvement of ≥1 grades of hydronephrosis. There were 9 pyeloplasty failures that were diagnosed and surgically corrected in a median of 7.5 months after the initial surgery. No clinical or surgical variables were associated with time to achieve ultrasonographic stabilization. DISCUSSION: There is great variability in the length of follow-up after pyeloplasty, ranging from 3-months to 7-years. In our cohort, the bast majority of patients had achieved ultrasonographic stabilization and displayed improvement in their initial grade of hydronephrosis by 14.5 months after surgery. Timeframe in which surgical failures were diagnosed and corrected. There were not clinical or surgical variables associated to time to achieve stabilization. Similar results have been reported in the literature; however, most of them have evaluated as their main outcome resolution and not stabilization of hydronephrosis. CONCLUSION: Ultrasonographic stabilization is a suitable and non-invasive parameter for determining the length of follow-up after unilateral pyeloplasty, as it is an adequate timeframe for identifying failed pyeloplasties, observing improvement or stabilization of hydronephrosis, and performing any additional procedure required after the primary repair.

Laparoscopic pyeloplasty as an alternative to nephrectomy in adults with poorly functioning kidneys due to ureteropelvic junction obstruction.

OBJECTIVES: To evaluate outcomes of laparoscopic pyeloplasty (LP) in adults with poorly functioning kidney due to ureteropelvic junction obstruction (UPJO). METHODS: A retrospective comparative analysis was performed between adult patients who underwent LP due to UPJO with differential renal function (DRF) ≤ 15% and DRF > 15%. LP success rate and complications were assessed. LP success was defined as symptoms improvement and DRF improvement or stabilization. DRF and estimated glomerular filtration rate (eGFR) were analyzed before and 12 months after surgery to evaluate renal function recovery. DRF was estimated using Tc-99 m DMSA renal scintigraphy. RESULTS: Among 121 LP performed in the study period at our institution, 15 and 42 were included in the DRF ≤ 15% and DRF > 15% groups, respectively. At a median follow-up of 17.8 months, all patients with DRF ≤ 15% reported symptoms improvement. LP success rate was 86.7% and 90.5% (p = 0.65) for patients with DRF ≤ 15% and DRF > 15%, respectively. There were no complications in the DRF ≤ 15% group, while there were three complications recorded in the DRF > 15% group (Clavien 2 and 3b). In the DRF ≤ 15% group, mean pre-operative and post-operative DRF was 9.5% ± 3.6 and 10.5% ± 7.8 (p = 0.49), respectively. Median pre-operative and post-operative eGFR was 68.5 ml/min and 79.8 ml/min (p = 0.93), respectively. Two patients had DRF improvement after LP. CONCLUSIONS: LP in adult patients with UPJO and poor function kidneys is an effective and safe procedure. DRF recovery is seen in a minority of the patients; however, LP is an alternative to nephrectomy.

Exploration the potential mechanism of the SIRT1 and its target gene FOXO1/PPARGC1A in uteropelvic junction obstruction.

BACKGROUND: Uteropelvic junction obstruction (UPJO) is a common surgical condition, which refers to the blockage of urine flowing through kidney into proximal upper ureter. However, the underlying mechanism of UPJO is poorly understood, especially the regulated and targeted genes of sirtuin 1 in UPJO. METHODS: We sequenced three renal tissues on the obstructed side of independent children with <20% differential renal function (DRF) and three samples with >40% DRF. Gene expression values were obtained and compared for differentially expressed genes (DEGs). Protein-protein interaction (PPI) analysis was conducted to identify the overlapping proteins of DEGs and Sirtuin 1 (SIRT1). The co-expression genes of overlapped genes were computed using Pearson correlation coefficient. The potential role of SIRT1 gene in UPJO was explored by resequencing 3 microarray data from RNA interference (RNAi) SIRT1 lines of renal tubular epithelial (NRK52E) cells in rat and three control datasets were sequenced again. The DEGs were obtained as parallel. GO/KEGG enrichment analysis and co-expression network were conducted to explore the underlying mechanism, particularly shared pathways or function in GO/KEGG enrichment analysis results. RESULTS: A total of 427 up-regulated genes and 1,099 down-regulated genes were identified among 3 mRNA-seq of renal tissue on the obstructed side of the independent children with <20% DRF and 3 samples with >40% DRF. According to prediction using the Search Tool for Retrieval of Interacting Genes/Proteins, 2 PPIs, FOXO1 and PPARGC1A, were identified among 2,524 DEGs, predicted as targets of SIRT1. Gene set enrichment analysis (GSEA) of their co-expression genes showed they may co-participate in biological activities including fatty acid degradation, regulation of signal transduction by p53 mediator. Moreover, GSEA results of DEGs was confirmed through RNAi SIRT1 lines of rat renal tubular epithelial (NRK52E) cells. CONCLUSIONS: UPJO may cause abnormal phenotypic changes of renal tubular epithelial cells through SIRT1/FOXO1 mediated protein transport, establishment of protein localization, and intracellular transport. In addition, UPJO is involved in regulation of signal transduction, regulation of intracellular estrogen receptor signaling pathways, and nucleoprotein localization through SIRT1/PPARGC1A-mediated p53 mediators, causing abnormal phenotypic changes in renal tubular epithelial cells.