Pediatric congenital hydronephrosis (ureteropelvic junction obstruction): Medical management guide

The first detailed annual record on the National Clinical Database Urology Division in Japan: A report on five surgical procedures

OBJECTIVES

The National Clinical Database (NCD) Urology Division commenced registration in April 2018 in Japan. This is the first report to focus on five surgeries for which detailed information is registered.

METHODS

We herein describe annual trends in and the complication grades of the following five surgeries: partial nephrectomy, radical nephrectomy, radical cystectomy, radical prostatectomy, and pyeloplasty, using the NCD. A total of 149 417 patients treated with the five types of surgeries based on NCD data were enrolled in this report.

RESULTS

The number of patients was 55 630 for partial/radical nephrectomy from April 2018 to December 2021, 83 653 for radical prostatectomy from April 2018 to December 2021, and 9342 for radical cystectomy from January 2020 to December 2021. In 2021, partial nephrectomy was performed on 7416 cases, radical nephrectomy on 7739 cases, radical prostatectomy on 22 692 cases, radical cystectomy on 4677 cases, and pyeloplasty on 792 cases.

CONCLUSIONS

The results obtained showed that a robot-assisted or laparoscopic procedure has replaced open surgery as the common approach for all five surgeries. An analysis of NCD data may be useful for understanding trends in surgical procedures across the major field of urology.

Associations between PM2.5, ambient heat exposure and congenital hydronephrosis in southeastern China

Objectives

This research aims to analyze how exposure to fine particulate matter (PM2.5) and ambient heat during pregnancy increases the risk of congenital hydronephrosis (CH) in newborns.

Methods

A case-control study was conducted to investigate the relationship between exposure to PM2.5 and ambient heat during pregnancy and the occurrence of CH in newborns. The study, which was conducted from 2015 to 2020, included 409 infants with CH as the case group and 409 infants without any abnormalities as the control group. Using spatial remote sensing technology, the exposure of each pregnant mother to PM2.5 concentration was meticulously mapped. Additionally, data on the ambient temperature of exposure for each participant were also collected. A logistics regression model was used to calculate the influence of exposure to PM2.5 and ambient heat on the occurrence of CH. Stratified analysis and interaction analysis were used to study the interaction between ambient heat exposure and PM2.5 on the occurrence of CH.

Results

At the 6th week of gestation, exposure to PM2.5 may increase the risk of CH. For every 10 μg/m3 increase in PM2.5 exposure, the risk of CH increased by 2% (95%CI = 0.98, 1.05) at a p-value of >0.05, indicating that there was no significant relationship between the results. Exposure to intense heat at 6th and 7th weeks of gestation increased the risk of CH. Specifically, for every 1°C increase in heat exposure, the risk of CH in offspring increased by 21% (95%CI = 1.04, 1.41) during the 6th week and 13% during the 7th week (95%CI = 1.02, 1.24). At 5th and 6th weeks of gestation, the relative excess risk due to interaction (RERI) was greater than 0 at the 50th percentile (22.58°C), 75th percentile (27.25°C), and 90th percentile (29.13°C) of daily maximum temperature (Tmax) distribution, indicating that the risk of CH was higher when exposed to both ambient heat and PM2.5 at the same time compared to exposure to a single risk factor.

Conclusion

Exposure to higher levels of PM2.5 and ambient heat during pregnancy increases the risk of CH in infants. There was a positive interaction between exposure to intense heat and high concentration of PM2.5 on the occurrence of CH.

Determining Split Renal Function in Children With Ureteropelvic Junction Stenosis: Technetium-99m Mercaptoacetyltriglycine (Tc-99m MAG-3) or Technetium-99m Dimercaptosuccinic Acid (Tc-99m DMSA)?

Background Ureteropelvic junction stenosis (UPJS) is the most common cause of clinically significant antenatal hydronephrosis. We compared separate renal function results obtained using technetium-99m-mercaptoacetyltriglycine (Tc-99m MAG-3) and technetium-99m-dimercaptosuccinic acid (Tc-99m DMSA) in pediatric patients with UPJS to evaluate the adequacy of Tc-99m MAG-3 scintigraphy and the necessity of additional Tc-99m DMSA scintigraphy during follow-up. Methodology Patients diagnosed with hydronephrosis in the Pediatric Nephrology Department of Pamukkale University Faculty of Medicine over a period of 10 years (2012-2022) were evaluated retrospectively. Patients who had been diagnosed with UPJS and underwent both Tc-99m MAG-3 and Tc-99m DMSA scintigraphy during follow-up were included in the study. Technetium-99m-labeled MAG-3 and DMSA scans were re-evaluated for all patients by the Department of Nuclear Medicine. Results The study included 52 children with unilateral UPJS (12 girls and 40 boys) with a mean age of 6.34 ± 4.81 years (range: 2.97-9.79 years). Thirty-six patients (69.2%) were diagnosed antenatally. Differential renal function in Tc-99m DMSA was 46.94 ± 10.64 and in Tc-99m MAG-3 was 43.08 ± 11.18; the functions were lower in Tc-99m MAG-3, but the values were within normal limits for both groups (p=0.0001, z=-3.893). When differential renal functions were compared between Tc-99m DMSA and Tc-99m MAG-3 results, a statistically significant positive and strong correlation was found in the kidney with ureteropelvic junction obstruction (UPJO) (p=0.0001, r=0.752). When classifying the Tc-99m MAG-3 and Tc-99m DMSA results in the kidney with UPJO (supranormal, normal, low function) for the determination of differential renal functions, there was a consistency of 76%, and it was correlated (p=0.0001, k=0.456). While two patients had supranormal function and 13 patients had low function in Tc-99m MAG-3, five patients had supranormal function, and eight patients had low function in Tc-99m DMSA. Conclusions Some studies in the literature have reported that Tc-99m MAG-3 causes supranormal function measurements in patients with UPJS; our results showed that Tc-99m DMSA resulted in a higher rate of supranormal values for affected kidneys. We believe that Tc-99m DMSA should not be performed in addition to Tc-99m MAG-3 scintigraphy in the follow-up of every patient with UPJS but can be utilized in select cases, such as patients with surgical indications and those suspected before surgery.

Analysis of risk factors for stenosis after laparoscopic pyeloplasty in the treatment of ureteropelvic junction obstruction

BACKGROUND

Laparoscopic ureteroplasty is an effective method for managing ureteropelvic junction obstruction. Despite its high success rate, there remains a subset of patients who do not experience improvement in the hydrops.

METHODS

The study retrospectively analyzed the data of 143 patients with ureteropelvic junction obstruction (UPJO) who underwent laparoscopic pyeloplasty (LP) in our hospital from January 2015 to May 2022. Logistic regression was used to analyze the risk factors of recurrence stenosis after UPJO.

RESULTS

Out of these patients, 119 had complete clinical data and follow-up records. Among these patients, restenosis occurred in nine cases after the operation. There was a significant statistical difference in blood loss (P < 0.05). Univariate and multivariate logistic regression analysis revealed that the preoperative separation degree of the renal pelvis, cystatin C, and intraoperative blood loss were potential risk factors for recurrent stenosis after primary LP. When divided by split renal function (SRF), the odds ratio (OR) was 7.850 (P = 0.044), indicating that it was an independent risk factor for postoperative restenosis. Similarly, the OR for stenotic segment length was 0.025 (P = 0.011), also indicating it as an independent risk factor for restenosis. The areas under the receiver operating characteristic curve for stenotic segment length and SRF were 0.9056 and 0.7697, respectively.

CONCLUSION

In our study, we identified that preoperative renal pelvis separation, cystatin C, and intraoperative blood loss were potential risk factors for postoperative restenosis. SRF and stenosis segment length were independent risk factors for postoperative restenosis.

Predicting clinically significant events in children with ureteropelvic junction obstruction

Introduction

Ureteropelvic junction obstruction (UPJO) syndrome is one of the most common causes of neonatal hydronephrosis. Management varies from simple monitoring to surgical intervention, with indications differing between institutions. A consensus of 8 societies recently described a new Urinary Tract Dilation (UTD) classification which aims to standardize ultrasound description of hydronephrosis, but which is also supposed to have predictive value in children with hydronephrosis. Our aim was to compare, in a monocentric prospective cohort of children with UPJO, the ability of UTD to predict the occurrence of a clinically significant event within the first year of life, as compared to anteroposterior diameter of the renal pelvis (APD).

Study design

We used a preexisting cohort of children followed in a prospective study on UPJO. A pediatric radiologist, blinded to the children's outcome, classified the last antenatal ultrasound and postnatal ultrasound according to the UTD-A and UTD-P classification. He also confirmed the APD-A and APD-P measures. We defined a clinically significant event as being: increased pelvic dilation (>5 mm) and/or the presence of a febrile urinary tract infection (fUTI) and/or impaired renal function on initial nuclear scan (<40%). We performed a ROC-AUC curve and Random Forest (RF) analysis to compare the ability of the APD-A, APD-P, UTD-A and UTD-P scores to predict a clinically significant event.

Results

The cohort included 28 children. Clinically significant events were noted in 20 out of 28 patients: 13 children presented an increase >5 mm in dilation, 6 presented an episode of fUTI and 9 had impaired function of the affected kidney. APD-A was the most effective individual criterion for predicting the occurrence of a significant clinical event (AUC = 0.867).

Conclusion

In our series, for children with UPJO, the most significant marker was prenatal APD >15 mm to predict an increase in dilation >5 mm.

Long-term follow-up of congenital hydronephrosis in a single-center study

OBJECTIVES

Many congenital hydronephroses spontaneously resolve. This study evaluated a long-term follow-up of more than 4 years of patients with congenital hydronephrosis at a single center.

METHODS

In total, 215 patients (286 kidneys) with congenital hydronephrosis were included. Hydronephrosis outcomes (resolution, improvement, and persistence) and time-to-outcome were evaluated.

RESULTS

Fourteen patients underwent early surgical intervention until the age of 2 years. A total of 189 congenital hydronephrosis cases (66%) showed resolution at a median of 16 months (interquartile range: 7-21 months) and 169 (80%) of 210 kidneys with grade I to II hydronephrosis showed resolution at a median of 14 months (interquartile range: 6-23 months). Of 76 kidneys with grade III to IV hydronephrosis, 24 (32%) showed resolution at a median of 29 months (interquartile range: 24-41 months), and 56 (74%) showed improvement to grade II or less at a median of 12 months (interquartile range: 5-23 months). Of the 76 kidneys with grade III to IV hydronephrosis, five required delayed pyeloplasty at a median of 66 months (interquartile range: 42-89 months). One patient was asymptomatic, with a marked worsening of hydronephrosis and decreased renal function 6 years after the resolution of hydronephrosis.

CONCLUSIONS

None of the patients with grade I to II hydronephrosis required surgical treatment, and a shorter follow-up may be sufficient. Grade III to IV severe hydronephrosis should be considered for a longer and more careful follow-up, given the possibility of asymptomatic exacerbation of hydronephrosis.

The Inhibition of Fibrosis and Inflammation in Obstructive Kidney Injury via the miR-122-5p/SOX2 Axis Using USC-Exos

Background: Fibrosis and inflammation due to ureteropelvic junction obstruction substantially contributes to poor renal function. Urine-derived stem-cell-derived exosomes (USC-Exos) have therapeutic effects through paracrine. Methods: In vitro, the effects of USC-Exos on the biological functions of HK-2 and human umbilical vein endothelial cells were tested. Cell inflammation and fibrosis were induced by transforming growth factor-β1 and interleukin-1β, and their anti-inflammatory and antifibrotic effects were observed after exogenous addition of USC-Exos. Through high-throughput sequencing of microRNA in USC-Exos, the pathways and key microRNAs were selected. Then, the antifibrotic and anti-inflammatory effects of exosomal miR-122-5p and target genes were verified. The role of the miR-122-5p/SOX2 axis in anti-inflammatory and antifibrotic effects was verified. In vivo, a rabbit model of partial unilateral ureteral obstruction (PUUO) was established. Magnetic resonance imaging recorded the volume of the renal pelvis after modeling, and renal tissue was pathologically analyzed. Results: We examined the role of USC-Exos and their miR-122-5p content in obstructive kidney injury. These Exos exhibit antifibrotic and anti-inflammatory activities. SOX2 is the hub gene in PUUO and negatively related to renal function. We confirmed the binding relationship between miR-122-5p and SOX2. The anti-inflammatory and antifibrotic effects of miR-122-5p were inhibited, indicating that miR-122-5p has anti-inflammatory and antifibrotic effects by inhibiting SOX2 expression. In vivo, the PUUO group showed typical obstructive kidney injury after modeling. After USC-Exo treatment, the shape of the renal pelvis shown a remarkable improvement, and inflammation and fibrosis decreased. Conclusions: We confirmed that miR-122-5p from USC-Exos targeting SOX2 is a new molecular target for postoperative recovery treatment of obstructive kidney injury.

Determination of tissue tracer transit of Technetium-99m-mercaptoacetyltriglycine diuretic renography in infants with suspected ureteropelvic junction obstruction - A multicenter prospective observational study

INTRODUCTION

There is an ongoing controversy regarding management of ureteropelvic junction obstruction in infants, with a shift towards a non-operative approach. However, precise predictors of outcome are lacking. Recent studies postulated a high prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit with regard to the development of an impaired differential renal function and its potential improvement following pyeloplasty.

OBJECTIVE

To evaluate the prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit for the occurrence of changes in differential renal function in infants with suspected unilateral ureteropelvic junction obstruction in a prospective observational multicenter study.

STUDY DESIGN

Infants below 3 months of age with a unilateral isolated hydronephrosis ≥ grade 3 received ultrasound and Technetium-99m-mercaptoacetyltriglycine diuretic renography at two different time points (timepoint 1 and timepoint 2). Data were analyzed at local centers and at the study center and were collected in an internet-based database system. Tissue tracer transit was determined for each diuretic renography, inter-observer variation for tissue tracer transit and standard parameters for judgement of differential renal function development were assessed.

RESULTS

Thirty-seven patients were analyzed. Median age was 11 weeks (7-15) at timepoint 1 and 26 weeks (19-33) at timepoint 2. A delayed tissue tracer transit at timepoint 1 was not associated with deterioration of differential renal function at timepoint 2 in both, locally (10/37 cases) and centrally (4/37) analyzed cases. However, sensitivity and specificity were poor. The intraclass correlation coefficient comparing local and central findings of tissue tracer transit and renal drainage demonstrated poor or fair agreement. Analysis of standard parameters for differential renal function development revealed a prognostic value only for the dichotomized anteroposterior renal pelvic diameter (APD, p = 0.03, 95%-CI 1.2-22.2).

DISCUSSION

Regarding the primary endpoint of our study, we could not confirm the hypothesis that delayed tissue tracer transit reliably predicts a subsequent decline in differential renal function in the cohort of patients studied. Whether the low age of the patients, technical problems in the correct assessment of tissue tracer transit by the investigator in early infancy, the study design, or the parameter itself played a role is debated.

CONCLUSION

In the presented setting tissue tracer transit was not useful as a predictive parameter for deterioration of differential renal function in infants with suspected unilateral ureteropelvic junction obstruction. Sensitivity and specificity of tissue tracer transit were not sufficient for risk stratification. Improved utility of tissue tracer transit as a marker might be achieved using a different study setting.

Combination of robot-assisted laparoscopic pyeloplasty for lower moiety ureteropelvic junction obstruction in a partial duplex system and percutaneous endoscopic surgery for renal calculi reusing the port for robotic pyeloplasty

Introduction

Ureteropelvic junction obstruction is often associated with renal calculus formation. However, there is no report of using robot-assisted laparoscopic pyeloplasty combined with percutaneous endoscopic surgery for ureteropelvic junction obstruction and renal calculi in a partial duplex system.

Case presentation

A 19-year-old female patient with lower moiety ureteropelvic junction obstruction and renal calculi in a partial duplex system was referred to our hospital because of left lumbar pain, left acute pyelonephritis, and an increase in left renal calculi during follow-up at the referral hospital. To prevent the complication of percutaneous nephrolithotripsy following pyeloplasty, robot-assisted laparoscopic pyeloplasty combined with percutaneous endoscopic surgery was performed. Two years after surgery, the patient reported no left lumbar pain.

Conclusion

The combination of robot-assisted laparoscopic pyeloplasty and percutaneous endoscopic surgery can be proposed as a safe and less-invasive treatment option for ureteropelvic junction obstruction and renal calculi in a partial duplex system.

Our experience of operated pediatric ureteropelvic junction obstruction patients

AIMS

Ureteropelvic junction obstruction (UPJO) may originate from extrinsic or intrinsic causes in children. The aim of this study is to present preoperative and postoperative data of our patients operated for UPJO.

METHODS

A total of 64 patients who underwent open pyeloplasty were investigated retrospectively. They were evaluated in terms of demographically, clinics, hydronephrosis, differential renal functions (DRFs), half-time tracer clearance (½TC), and histopathologic results. Patients' numerical results were stated as mean ± standard deviation (SD).

RESULTS

Male gender was more prevalent (n = 47, 73.4%) and mean age at surgery was 46.87 months. UPJO was located at the left side in 56.3% (n = 36), and at the right side in 39.1% (n = 25) of patients. It was bilateral in 4.7% (n = 3). Hydronephrosis was found antenatally in 68.8% (n = 44) of patients. The mean preoperative DRF was 49.7% (21-78%) and mean postoperative DRF was 49.2% (20-56%). Mean renal scintigraphic t1/2 was >20 min for all patients. The mean AP diameter was 21.58 mm (10-62 mm). Muscular hypertrophy was the most common pathological finding, mean length of excised segment was 10.26 mm (3-40 mm). Crossing vessel (CV) was detected in 17.18% (n = 11). The CV was statistically associated with increased age of operation, left side, and female gender. Statistically significant hydronephrosis was found in non-CV patients. Re-operation was required in seven patients (7.8%).

CONCLUSIONS

Intrinsic pathologies are more seen in the etiology of UPJO patients with antenatal diagnosis and this group needs operation at an earlier age. However, CV is found more commonly in patients who are diagnosed and operated at older ages.

Diagnostic value of diuretic ultrasound in evaluating the need for reoperation in children undergoing pyeloplasty

Background

Pyeloplasty currently stands as the standard treatment for UPJO. Our study aimed to assess the diagnostic value of sonographic parameters following Lasix administration in patients who underwent pyeloplasty to predict the recurrence of obstruction and the need for reoperation.

Methods

The study included 70 children with UPJO who underwent pyeloplasty. Renal ultrasound was performed on patients three to six months after pyeloplasty. Following the Lasix administration, the changes in ultrasound parameters at the 18th and 30th minute were documented. Within two weeks, patients underwent radioisotope renography. Diuretic ultrasound's diagnostic value in predicting the need for reoperation was assessed through a comparison with radioisotope renography.

Results

The average age of the patients was 3.94 ± 3.52 years. Anteroposterior diameter of the renal pelvis (APD) changes at 18 and 30 min, and the average APD after surgery at 18 and 30 min was significantly higher in patients requiring reoperation. The best cutoff point of APD changes in the 18th minute was 9.50 (sensitivity = 91.7%, specificity = 82.8%). The best cutoff point of APD after surgery in the 18th minute was 25.90 (sensitivity = 91.7%, specificity = 81.0%). The best cutoff points of the resistive index (RI) in the 18th and 30th minutes were reported as 0.70 (sensitivity = 41.7%, specificity = 50.0%) and 0.71 (sensitivity = 41.7%, specificity = 37.9%), respectively.

Conclusions

The assessment of ultrasound findings following pyeloplasty has revealed that changes in APD can serve as a reliable means for assessing the efficacy of the operation.

Laparoscopic versus robot-assisted pyeloplasty in infants and young children

OBJECTIVE

To compare the characteristics of conventional laparoscopic pyeloplasty (LP) and robotic-assisted laparoscopic pyeloplasty (RALP) in infants and young children with ureteropelvic junction obstruction (UPJO).

METHODS

We performed a retrospective study of patients (age: 0-36 months) who underwent dismembered pyeloplasty (Anderson-Hynes) with the fourth-generation RALP or traditional LP between April 2020 and December 2020.

RESULTS

A total of 33 patients with UPJO were enrolled: 12 underwent RALP (9 left side; 3 right side) and 21 underwent LP (18 left side; 3 right side). In the RALP group, the median patient age was 17 months (range: 5-36 months). In the LP group, the median patient age was 9 months (range: 2-36 months) (P = 0.182). The mean operation times were 120.25 ± 37.54 min (RALP) and 156.10 ± 51.11 min (LP) (P = 0.042), and the mean lengths of hospital stay were 6.42 ± 1.62 days (RALP) and 8.19 ± 2.25 days (LP) (P = 0.023). Removal of the drainage tube was performed after 3.08 ± 0.69 days (RALP) and after 4.76 ± 1.81 days (LP) (P = 0.001). The postoperative pain showed no significant difference. The mean hospitalization costs were 61464.75 ± 2800.53 yuan (RALP) and 22169.52 ± 3442.15 yuan (LP) (P < 0.001). The mean follow-up time was 10-18 months. Significant improvements in the anteroposterior diameter and parenchymal thickness were observed after surgery. Conversion to laparotomy was not performed. No short-term complications occurred during postoperative hospitalization and follow-up.

CONCLUSION

RALP has the advantages of less trauma and faster recovery. It can be safely and effectively performed in infants and young children, and its effectiveness is similar to that of traditional LP.

Pediatric Minimally Invasive Surgery-A Bibliometric Study on 30 Years of Research Activity

Background: Pediatric minimally invasive surgery (MIS) is a standard technique worldwide. We aimed to analyze the research activity in this field. Methods: Articles on pediatric MIS (1991−2020) were analyzed from the Web of Science™ for the total number of publications, citations, journals, and impact factors (IF). Of these, the 50 most cited publications were evaluated in detail and classified according to the level of evidence (i.e., study design) and topic (i.e., surgical procedure). Results: In total, 4464 publications and 53,111 citations from 684 journals on pediatric MIS were identified. The 50 most cited papers were published from 32 institutions in the USA/Canada (n = 28), Europe (n = 19), and Asia (n = 3) in 12 journals. Four authors (USA/Europe) contributed to 26% of the 50 most cited papers as first/senior author. Hot topics were laparoscopic pyeloplasty (n = 9), inguinal hernia repair (n = 7), appendectomy, and pyloromyotomy (n = 4 each). The majority of publications were retrospective studies (n = 33) and case reports (n = 6) (IF 5.2 ± 3.2; impact index 16.5 ± 6.4; citations 125 ± 39.4). They were cited as often as articles with high evidence levels (meta-analyses, n = 2; randomized controlled trials, n = 7; prospective studies, n = 2) (IF 12.9 ± 22.5; impact index 14.0 ± 6.5; citations 125 ± 34.7; p > 0.05). Conclusions: Publications on laparoscopic pyeloplasty, inguinal hernia repair, appendectomy, and pyloromyotomy are cited most often in pediatric MIS. However, the relevant number of studies with strong evidence for the advantages of MIS in pediatric surgery is missing.

Acute bilateral ureteropelvic junction obstruction as a rare cause of hypertensive crisis: a case report

Background

Bilateral ureteropelvic junction obstruction is a common cause of secondary hypertension in the pediatric population, often due to congenital malformation. On the other hand, it is less frequently encountered in the adult population and is usually due to an acquired condition, most commonly by a bilaterally obstructing nephrolithiasis causing hydronephrosis and subsequent hypertension. The aim of this study was to investigate and highlight the underlying mechanisms by which acute bilateral ureteropelvic junction obstruction causes hypertensive crisis and why early detection and prompt treatment are necessary to mitigate the effects of elevated blood pressure on target organs.

Case presentation

A 41-year-old African American man with hypertensive cardiomyopathy presented with anuria. He was found to have elevated blood pressure with evidence of target organ damage on laboratory examination, demonstrated by sudden elevation of his serum creatinine level. He was initially treated with oral and intravenous antihypertensives, with minimal improvement. The work-up was unremarkable apart from the imaging finding of acute bilateral ureteropelvic junction obstruction from obstructing nephrolithiasis causing hydronephrosis. Bilateral ureteral stents were placed for decompression, with resolution of the hypertensive crisis and improvement of renal function.

Conclusion

This case highlights the importance of prompt diagnosis and treatment of underlying acute bilateral ureteropelvic junction obstruction to mitigate the deleterious effects of sudden blood pressure elevation on target organs.

Attaining competency and proficiency in open pyeloplasty: a learning curve configuration using cumulative sum analysis

INTRODUCTION

The learning curves for minimally invasive pyeloplasty techniques have been described in the past. However, the learning curve in achieving competency in open pyeloplasty has not been described. Hence, we aim to evaluate a single surgeon series of open pyeloplasty technique using the cumulative sum (CUSUM) methodology.

METHODS

We retrospectively reviewed all open pyeloplasties performed by a single surgeon (AJL) between January 2008 and March 2020. Collected variables included: sex, age at surgery, operative time, hospital stay, pre-operative ultrasound, pre-operative nuclear scans, pre-operative anteroposterior diameter, associated anomalies, laterality (left or right), type of stent, pre-operative split renal function, and duration of follow-up. A CUSUM analysis was used: the highest peak, plateau and downward trends for complications (defined as Clavien-Dindo classification ≥ 3b) were identified on the plot and set as the transition points between five phases (learning, competency, proficiency, case-mix, and mastery).

RESULTS

Based on the CUSUM analysis, the index surgeon reached the competency phase after performing their 13th open pyeloplasty and became proficient after the 70th case. In the case-mix phase (104th-126th cases), where the surgeon may be performing more complex cases while increasing trainee involvement, there was a slight increase in complication rates. After the 126th case, the surgeon entered the mastery phase, where there was consistent decreasing trend in complications.

CONCLUSIONS

Surgeons performing open pyeloplasty in children following completion of their surgical training will continue to learn through their early cases until achieving competency. Technical competency may be reached after the 13th case. In this report, we looked at the number of cases to become proficient in open pyeloplasty procedure in children. A surgeon may achieve technical proficiency in the procedure after their 13th case.

Acute renal failure due to severe bilateral ureteropelvic junction obstruction treated by urinary drainage in a 2-year-old infant

INTRODUCTION

Conscientious follow-up is essential for bilateral grade 4 hydronephrosis with ureteropelvic junction obstruction to ensure optimal surgical timing. We have reported a case of a male infant who required emergent urinary drainage due to severe bilateral ureteropelvic junction obstruction-derived acute renal failure.

CASE PRESENTATION

Bilateral grade 4 hydronephrosis was diagnosed in a male neonate. Vesicoureteral reflux was ruled out. Two years after the initial diagnosis, he developed acute renal failure and underwent bilateral emergent urinary drainage, followed by multiple urinary tract reconstructions against left ureterovesical junction stenosis and bilateral ureteropelvic junction obstruction. The postoperative renogram demonstrated a bilateral nonobstructive pattern.

CONCLUSION

Bilateral emergency drainage for acute renal failure was successful without hemodialysis. Unilateral drainage or pyeloplasty should be planned early for bilateral grade 4 hydronephrosis with ureteropelvic junction obstruction to avoid lethal events if the obstruction pattern with decreased split renal function is <40% or if it is symptomatic.

The effect and molecular mechanism of hypoxia on proliferation and apoptosis of CD133+ renal stem cells

Congenital hydronephrosis caused by ureteropelvic junction obstruction (UPJO) eventually leads to renal interstitial fibrosis and atrophy, after a series of pathophysiological problems. Renal repair after injury depends on renal stem cells. This study aimed to determine the expression of renal stem cell marker CD133 in children of different ages and the regulatory effect of stem cell microenvironment. Renal stem cells from children of different ages were identified and screened out by flow cytometry in the study. Children with hydronephrosis were divided into neonates, infants, preschool age, school age, and adolescents groups. A hypoxic cell model prepared with CoCl₂ was developed to detect the effect of hypoxia on the proliferation and apoptosis of renal stem cells. The effect and molecular mechanism of hypoxia-inducible factor 1-alpha (HIF-1α) on the proliferation and apoptosis of renal stem cells were also explored. Both hypoxia and HIF-1α significantly promoted the proliferation of renal stem cells and inhibited cell apoptosis. HIF-1α could bind to the promoter region of proliferating cell nuclear antigen (PCNA) and PROM1 (CD133) to mediate their transcription and expression. The content of CD133⁺ renal stem cells was the highest in the neonatal group and it decreased with the increase of age. Taken together, this study clarified the effect of age on the content of human renal stem cells and determined the regulatory mechanism of hypoxia on renal stem cells. We expect our results to provide a research basis for the treatment and clinical application of renal stem cells.

Asymptomatic obstructive hydronephrosis associated with diabetes insipidus: a case report and review

The treatment of asymptomatic hydronephrosis due to ureteropelvic junction obstruction (UPJO), as well as the timing and indications for surgical intervention, remain controversial. Diabetes insipidus (DI) is a rare disease in infants that is known to cause non-obstructive hydronephrosis, while its association with obstructive hydronephrosis has not been reported. Some studies have found that increased water intake is a predisposing risk factor of developing hydronephrosis. However, there are no studies or guidelines that indicate the specific follow-up intervals and surgical indications for mild hydronephrosis if predisposing risk factors persist. A 46-month-old boy was admitted to our Urology Department with a history of Society of Fetal Urology (SFU) Grade 2 prenatal left hydronephrosis, which was stable at SFU Grade 1-2 at regular postnatal follow-ups. The patient developed polydipsia and polyuria three months prior to admission, then he was considered as primary polydipsia by endocrinology and was treated with fluid restriction while the examination was negative. Renal ultrasound at follow-up demonstrated severe left hydronephrosis with an anterior-posterior diameter (APD) of 6.25 cm three months after symptom onset. Diuretic renography (DR) revealed a renal function of 13.7% with a glomerular filtration rate (GFR) of 11.25 mL/min. The patient was otherwise asymptomatic without any abdominal pain or vomiting. He underwent left pyelostomy immediately as well as laparoscopic left dismembered ureteropelvioplasty after three months, and a diagnosis of UPJO was confirmed. The patient had an uncomplicated postoperative recovery and the result of follow-up renal ultrasound was stable. However, the symptoms of polydipsia and polyuria did not improve significantly. He underwent pituitary magnetic resonance imaging (MRI) and pathological examination, the results of which were consistent with central DI caused by Langerhans cell hyperplasia four months postoperatively. This case indicates the need to pay attention to children with mild hydronephrosis undergoing regular observation and conservative treatment, as a sudden aggravation of the hydronephrosis and a rapid decline of renal function may occur if DI persists.

Association between severity of prenatally diagnosed hydronephrosis and receipt of surgical intervention postnatally among patients seen at a fetal-maternal center

Background

Hydronephrosis (HN) is the most common abnormality detected on prenatal ultrasound. This study sought to stratify outcomes of patients by severity of prenatal HN with postnatal outcomes.

Methods

This was a retrospective review of patients referred to a tertiary care fetal-maternal clinic with diagnosis of prenatal HN from 2004 to 2019. HN severity was categorized as mild, moderate, or severe. Data were analyzed to determine the association between HN severity and surgical intervention. Decision for surgery was based on factors including history of multiple urinary tract infections, evidence of renal scarring, and/or reduced renal function. Surgery-free survival time was represented by the Kaplan–Meier method, and hazard ratios were calculated using the log-rank test.

Results

131 kidneys among 101 infants were prenatally diagnosed with hydronephrosis; 35.9% had mild HN, 29.0% had moderate HN, and 35.1% had severe HN. 8.5% of patients with mild HN, 26.3% of patients with moderate HN, and 65.2% of patients with severe HN required surgery. Patients with severe HN were 12.2 (95% CI 6.1–24.4; p < 0.001) times more likely to undergo surgery for HN than patients with mild HN and 2.9 (95% CI 1.5–5.3; p = 0.003) times more likely to undergo surgery than patients with moderate HN. Patients with moderate HN were 4.3 times more likely to require surgery than patients with mild HN (95% CI 1.5–12.9; p = 0.01). Median age at surgery was 11.8 months among patients with mild HN (IQR 11.7–14.1 months), 6.6 months among patients with moderate HN (IQR 4.2–16.4 months), and 5.4 months among patients with severe HN (3.7–12.4 months).

Conclusion

Among this cohort of referrals from a fetal-maternal clinic, severity of HN correlated with increased likelihood of surgical intervention. Continued assessment of patients with prenatal HN should be evaluated to best determine the role of the pediatric urologist in cases of prenatal HN.

Meta-Analysis of the Efficacy of Laparoscopic Pyeloplasty for Ureteropelvic Junction Obstruction via Retroperitoneal and Transperitoneal Approaches

Objective: This study aimed to evaluate the clinical efficacy of laparoscopic pyeloplasty (LP) for ureteropelvic junction obstruction (UPJO) via retroperitoneal and transperitoneal approaches. Method: A systematic literature search on keywords was undertaken using PubMed, Cochrane Library, Embase, China Nation Knowledge (CNKI), and Wanfang. The eligible literature was screened according to inclusion and exclusion criteria. Meta-analysis was performed by using RevMan 5.0 software. Results: According to the inclusion and exclusion criteria, 12 studies were identified with a total of 777 patients. Four hundred eight patients were treated with retroperitoneal laparoscopic pyeloplasty (RLP), and 368 patients were treated with transperitoneal laparoscopic pyeloplasty (TLP). The meta-analysis results showed that the two approaches were similar in terms of presence of postoperative hospital stay, postoperative complication, the rate of conversion, and recurrence (p > 0.05). The operative time in the TLP group was significantly shorter than the RLP group (MD = 16.6; 95% CI, 3.40-29.80; p = 0.01). The duration of drainage was significantly shorter (MD = -1.06; 95% CI, -1.92 to -0.19; p = 0.02), and the score of postoperative visual analog score (VAS) was significantly lower in the RLP group than in the TLP group (MD = -0.52; 95% CI, -0.96 to -0.08; p = 0.02). Conclusion: Both approaches have good success rates and low postoperative complication rates. RLP provides a shorter duration of drainage and lower VAS score, but it takes more operative time than TLP.

Urine Biomarkers Combined With Ultrasound for the Diagnosis of Obstruction in Pediatric Hydronephrosis

Introduction: To establish the efficacy of ultrasound (US) combined with urine biomarkers in differentiating patients who require surgical management from those who do not, avoiding invasive investigations. Materials and Methods: From February 2019 to February 2021, all pediatric patients who presented with hydronephrosis were selected for the study. All renal units (RU) were evaluated by US, and fresh frozen voided urine samples were collected at the time of inclusion. Hydronephrosis grade was evaluated by the Society for Fetal Urology (SFU) and an alternative grading system (AGS). Patients who had high-grade hydronephrosis on US were referred to renal scan (RS) or intervention, when there was an increase of dilatation in subsequent follow-up images. Fresh frozen urine from the control group with no history of renal diseases and no renal anomalies on US was collected. We compared differences of US parameters combined with urine biomarkers between surgically and non-surgically managed patients and between the groups of patients when they were stratified by different RS findings and analyzed whether urinary biomarkers give any additional value to US. Instead of the anterior-posterior diameter (APD), we used its ratio with mid-parenchymal thickness. The additional efficacy of biomarkers to US was calculated when the US component was derived to a cumulative APD/mid-parenchymal ratio. Results: Sixty-four patients with hydronephrosis were prospectively included in the study accounting for a total of 81 patient visits and 162 RUs evaluated. A control group of 26 patients was collected. The mean age at inclusion in the hydronephrosis group was 43.7(±45.5) months, and a mean age in a control group was 61.2(±41.3) months. The cumulative APD/mid-parenchymal ratio combined with urinary albumin, β2 microglobulin (β2-M), and urinary neutrophil gelatinase-associated lipocalcin may have a better performance in the prediction of surgical intervention than the cumulative APD/mid-parenchymal ratio alone (p = 0.1). The best performance to detect the increased tissue transit time and obstructive curve on RS was demonstrated by the β2-M creatinine ratio. An increased cumulative APD/mid-parenchymal ratio with biomarkers together had a fairly good sensitivity and specificity for detection of DRF < 40%. Conclusions: According to our data, the APD/mid-parenchymal ratio alone has good efficacy in prediction of surgery and abnormal RS findings especially when combined with urine biomarkers.

Meta-analysis of retroperitoneal vs transperitoneal laparoscopic and robot-assisted pyeloplasty for the management of pelvi-ureteric junction obstruction

OBJECTIVE

To determine differences in perioperative outcomes between retroperitoneal and transperitoneal approaches for laparoscopic pyeloplasty (LP) to manage pelvi-ureteric junction obstruction (PUJO) through a meta-analysis of comparative studies.

METHODS

A systematic search was performed in January 2020. Comparative studies were evaluated according to Cochrane Collaboration recommendations. Assessed outcomes included success and complication rates, conversion to open surgery, operative time (OT), length of hospital stay (LOS), estimated blood loss (EBL), analgesic requirements, regular diet resumption, and drain duration. Relative risk (RR) and standardised mean difference (SMD) with 95% confidence intervals (CIs) were extrapolated. Subgroup analyses were performed according to study design and techniques. International Prospective Register of Systematic Reviews (PROSPERO) number: CRD42020163303.

RESULTS

A total of 18 studies describing 2007 cases were included. Overall pooled effect estimates did not show statistically significant differences between the approaches with regards to success rate (RR 0.99; 95% CI 0.97, 1.01), complications (RR 1.09; 95% CI 0.82, 1.45), OT (SMD 0.61; 95% CI -0.04, 1.26), LOS (SMD -0.30; 95% CI -0.63, 0.04), EBL (SMD -0.53; 95% CI -1.26, 0.21), or analgesic requirements (SMD -0.51; 95% CI -1.23, 0.21). Compared to the transperitoneal approach, retroperitoneal LP had a higher conversion rate (RR 2.40; 95% CI 1.23, 4.66); however, patients resumed diets earlier (SMD -2.49; 95% CI -4.17, -0.82) and had shorter drain duration (SMD -0.31; 95% CI -0.57, -0.05).

CONCLUSION

The evidence suggests that there are no significant differences in success rate, OT and complications between transperitoneal and retroperitoneal LP. Conversion rates are higher with the retroperitoneal approach; however, return to diet occurs faster and drain duration is shorter when compared to the transperitoneal approach.

Appropriate timing of performing abdominal ultrasonography and termination of follow-up observation for antenatal grade 1 or 2 hydronephrosis

Background

Most cases of antenatal the Society of Fetal Urology (SFU) grade 1or 2 hydronephrosis (HN) improve or resolve spontaneously with conservative treatment. However, there is no consensus on the duration of follow-up for cases of grade 1or 2 HN. The aim of this study was to determine the need for continuous follow-up period and new management of children with antenatal grade 1or 2 HN.

Methods

Subjects underwent ultrasonographic assessment for HN according to the SFU classification. We retrospectively evaluated 112 patients with postnatal grade 1 HN and 69 with grade 2 HN using abdominal ultrasonography between January 2010 and December 2017. We examined the change in HN grade on repeat ultrasonography. Kaplan–Meier method was used to show the effect of HN grade on the rate of HN changes.

Results

The mean follow-up duration was 44.9 ± 36.4 months (range 12–274). Initial SFU grade 1 HN disappeared in 47.0% of cases at 12 months, 66.4% at 24 months and 73.2% at 48 months. Initial SFU grade 2 HN showed improvement in grade in 74.7% of cases at 12 months, 88.3% at 24 months and 89.5% at 48 months. However, 14.6% of SFU grade 1 and 2.8% of SFU grade 2 cases increased in grade and of the 17 cases, 16 cases worsened within the first 6 months. No cases with increased grade required pyeloplasty. Initial disappearance and later reappearance of HN occurred in 40.5% of SFU grade 1 and 2 cases. The mean duration of later reappearance of HN was 39.1 ± 36.2 months (range 12–137). No cases showed reappearance of HN after more than 1 year.

Conclusions

Ultrasonography within the first 6 months was necessary for management of children with antenatal grade 1or 2 HN, because some patients showed worsening. After that, it is considered safe to spread the follow-up interval for stable cases. Most cases of grade 1or 2 HN resolved spontaneously, however a few cases reappeared within 1 year. Therefore, ultrasonography after 1 year was necessary in children with HN that spontaneously disappeared. The appropriate time to end the follow-up was considered to have been after 1 year or more has passed since the disappearance was confirmed.