OXGR1 is a candidate disease gene for human calcium oxalate nephrolithiasis.

PURPOSE: Nephrolithiasis (NL) affects 1 in 11 individuals worldwide, leading to significant patient morbidity. NL is associated with nephrocalcinosis (NC), a risk factor for chronic kidney disease. Causative genetic variants are detected in 11% to 28% of NL and/or NC, suggesting that additional NL/NC-associated genetic loci await discovery. Therefore, we employed genomic approaches to discover novel genetic forms of NL/NC. METHODS: Exome sequencing and directed sequencing of the OXGR1 locus were performed in a worldwide NL/NC cohort. Putatively deleterious, rare OXGR1 variants were functionally characterized. RESULTS: Exome sequencing revealed a heterozygous OXGR1 missense variant (c.371T>G, p.L124R) cosegregating with calcium oxalate NL and/or NC disease in an autosomal dominant inheritance pattern within a multigenerational family with 5 affected individuals. OXGR1 encodes 2-oxoglutarate (α-ketoglutarate [AKG]) receptor 1 in the distal nephron. In response to its ligand AKG, OXGR1 stimulates the chloride-bicarbonate exchanger, pendrin, which also regulates transepithelial calcium transport in cortical connecting tubules. Strong amino acid conservation in orthologs and paralogs, severe in silico prediction scores, and extreme rarity in exome population databases suggested that the variant was deleterious. Interrogation of the OXGR1 locus in 1107 additional NL/NC families identified 5 additional deleterious dominant variants in 5 families with calcium oxalate NL/NC. Rare, potentially deleterious OXGR1 variants were enriched in patients with NL/NC compared with Exome Aggregation Consortium controls (χ2 = 7.117, P = .0076). Wild-type OXGR1-expressing Xenopus oocytes exhibited AKG-responsive Ca2+ uptake. Of 5 NL/NC-associated missense variants, 5 revealed impaired AKG-dependent Ca2+ uptake, demonstrating loss of function. CONCLUSION: Rare, dominant loss-of-function OXGR1 variants are associated with recurrent calcium oxalate NL/NC disease.

Hybrid Clinics: A New Model for Ambulatory Care to Reduce Infection Risk.

Objectives: To assess the viability of a hybrid clinic model combining in-person examination with video-based consultation to minimize viral transmission risk. Methods: Data were collected prospectively in a pediatric urology clinic for in-person visits from January to April 2018 ("classic") and hybrid visits from October to December 2020 of the COVID-19 pandemic ("hybrid"). Variables included provider, diagnosis, patient type, time of day, prior surgery, postoperative status, and decision-making for surgery. The primary outcome was "room time" or time in-person. The secondary outcome was "total time" or visit duration. Proportion of visits involving close contact (room time ≥15 min) was assessed. Univariate analyses were performed using the Wilcoxon rank-sum test and Fisher's exact test. Mixed models were fitted for visit approach and other covariates as fixed effects and provider as random effect. Results: Data were collected for 346 visits (256 classic, 90 hybrid). Hybrid visits were associated with less room time (median 3 min vs. 10 min, p < 0.001) but greater total time (median 13.5 min vs. 10 min, p = 0.001) as compared with classic visits. On multivariate analysis, hybrid visits were associated with 3 min less room time (95% confidence intervals [CIs]: -5.3 to -1.7, p < 0.001) but 3.8 min more total time (95% CI: 1.5-6.1, p = 0.001). Close contact occurred in 6.7% of hybrid visits, as compared with 34.8% of classic visits (p < 0.001). Conclusions: Hybrid clinic visits reduce room time as compared with classic visits. This approach overcomes the examination limitations of telemedicine while minimizing viral transmission, and represents a viable model for ambulatory care whenever close contact carries infection risk.

Comparing Pediatric Ureteroscopy Outcomes with SuperPulsed Thulium Fiber Laser and Low-Power Holmium:YAG Laser.

PURPOSE: The thulium fiber laser is a promising new lithoptripsy technology never before studied in the pediatric population. Our center adopted the first platform in North America, the SuperPulsed thulium fiber laser (SPTF). We aimed to compare outcomes in pediatric ureteroscopy using the SPTF to those using the gold standard, low-power holmium:yttrium-aluminum-garnet (Ho:YAG) laser. MATERIALS AND METHODS: This is a retrospective, consecutive cohort study of unilateral ureteroscopy with laser lithotripsy performed in pediatric patients from 2016 to 2021 as an early adopter of the SPTF. Thirty-day complications and stone-free status, defined as the absence of a stone fragment on followup imaging within 90 days, were analyzed using logistic regression. Operative times were compared using linear regression. Propensity scores for use of SPTF were used in regression analyses to account for potential cohort imbalance. RESULTS: A total of 125 cases were performed in 109 pediatric patients: 93 with Ho:YAG and 32 with SPTF. No significant difference was noted in age (p=0.2), gender (p=0.6), stone burden (p >0.9) or stone location (p=0.1). The overall stone-free rate was 62%; 70% with SPTF and 59% with Ho:YAG. The odds of having a residual stone fragment were significantly lower with SPTF than with Ho:YAG (OR=0.39, 95% CI: 0.19-0.77, p=0.01). There was no significant difference in operative time (p=0.8). Seven (25%) complications were noted with SPTF and 19 (22%) with Ho:YAG (p=0.6). CONCLUSIONS: The SPTF laser was associated with a higher stone-free rate than the low-power Ho:YAG laser without compromising operative time and safety.

Malignancy Yield of Testis Pathology in Older Boys and Adolescents with Cryptorchidism.

PURPOSE: We performed a retrospective, single-institution study to characterize the pathological findings of testis tissue specimens from older boys and adolescents with cryptorchidism. MATERIALS AND METHODS: With institutional review board approval, pathology reports were obtained for testicular specimens from patients age 10 years or older at a pediatric hospital from 1994 to 2016. Reports were excluded if they lacked clinical records, lacked testicular parenchyma, were from a descended testis or were from a patient with differences of sexual development. Variables of interest included age, testis location, procedure and pathological findings. Presence of malignancy among intra-abdominal versus extra-abdominal undescended testes was compared using Fisher's Exact Test. RESULTS: Seventy-one patients met inclusion criteria. The median age was 15.3 years (range 10.1-27.7). None had a history of testicular malignancy. Forty-five unilateral orchiectomies, 22 unilateral orchiopexies with biopsy and 4 bilateral procedures were performed. Seventeen testes (22.7%) were intra-abdominal, 42 (56.0%) were in the inguinal canal, 9 (12.0%) were at the external inguinal ring, 3 (4.0%) were in the superficial inguinal pouch and 4 (5.3%) were in the scrotum. Malignancy was detected in 2/71 patients (2.8%). By location, 2/16 patients (12.5%) with intra-abdominal testis and 0/55 patients (0%) with extra-abdominal testis demonstrated malignancy (p=0.048). CONCLUSIONS: Among males with cryptorchidism ages 10 years and older without differences of sexual development, 2/16 patients with intra-abdominal testis and 0/55 patients with extra-abdominal testis demonstrated malignancy. In older boys and adolescents, orchiectomy or biopsy is indicated for intra-abdominal testes but may not be necessary for extra-abdominal undescended testes.

Dietary Risk Factors for Pediatric Kidney Stones: A Case-Control Study.

PURPOSE: Data are scarce regarding dietary risk factors for pediatric nephrolithiasis. Our objective was to perform a case-control study (nonmatched) of the association of dietary nutrients with pediatric urolithiasis. MATERIALS AND METHODS: We obtained dietary information from pediatric urolithiasis patients (from stone clinic in 2013-2016) and healthy controls (well-child visit at primary care in 2011-2012). Survey results were converted to standard nutrient intakes. Children younger than 5 years of age and those with extreme calorie intake values (<500 or >5,000 kcal/day) were excluded. The association of individual nutrients with urolithiasis was assessed by bivariate analysis results and machine-learning methods. A multivariable logistic regression model was fitted using urolithiasis as the outcome. RESULTS: We included 285 patients (57 stones/228 controls). Mean±SD age was 8.9±3.6 years (range 5-20). Of the patients 47% were male. After adjusting for age, sex, body mass index (obese/overweight/normal), calorie intake and oxalate, urolithiasis was associated with higher dietary sodium (OR=2.43 [95% CI=1.40-4.84] per quintile increase, p=0.004), calcium (OR=1.73 [95% CI=1.07-3.00] per quintile increase, p=0.034) and beta carotene (OR=2.01 [95% CI=1.06-4.18] per quintile increase, p=0.042), and lower potassium (OR=0.31 [95% CI=0.13-0.63] per quintile increase, p=0.003). Sensitivity analysis was performed by removing oxalate from the model and limiting the sample to patients aged 5-13 years, with similar results. CONCLUSIONS: In our cohort, higher dietary intake of calcium, sodium and beta carotene, and lower potassium intake were associated with pediatric urolithiasis. This is the first study using a detailed dietary survey to identify dietary risk factors for pediatric urolithiasis. Further research is warranted to delineate the mechanisms and to generate a lower risk diet profile for pediatric urolithiasis.

Normative values for ureteral diameter in children.

BACKGROUND: Assessment of the ureter is a fundamental part of the radiologic evaluation of the urinary tract. Abnormal ureteral dilation warrants further investigation to assess the etiology, which includes obstruction and/or reflux. Despite this fundamental need, there are no established normative values in children based on imaging. OBJECTIVE: To provide normative values for ureteral diameter in pediatric patients with age-related ranges. MATERIALS AND METHODS: We retrospectively reviewed all magnetic resonance (MR) urography studies and chose only normal ureters for assessment. The images were analyzed on commercially available software to assess maximum internal diameter. Manual measurements were done in cases where the images were below the resolution for automated assessment. Maximum intraluminal ureteral diameters were measured in upper, mid and lower thirds and the average of the three maximum ureteral diameters was used to obtain the average widest internal ureteral diameter. Multivariable linear regression was performed to test the association between the calculated diameter and gender. Differences in sizes between the left and right ureter were assessed using paired Wilcoxon signed rank test. RESULTS: One hundred twenty-one MR urography studies were selected, which included 160 ureter units. The diameter increases progressively with age, ranging from 3.2 mm during infancy to 5.0 mm in patients older than 16 years of age. After 9 years of age, the average widest internal ureteral diameter is slightly larger in males compared to females (odds ratio [OR]=1.91, 95% confidence interval [CI] [1.63, 2.25], P<0.0001). The right ureter was slightly larger than the left (3.9 mm vs. 3.7 mm, P=0.004) among 39 patients in whom both right and left ureter units were included. The average mid ureteral diameter is widest, followed by the distal third then proximal third. CONCLUSION: We present the normative values for the average widest internal ureteral diameter based on laterality and different segments. In the pediatric population, 3.8 mm should be considered the average widest internal ureteral diameter.

Top-Down versus Bottom-Up Approach in Children Presenting with Urinary Tract Infection: Comparative Effectiveness Analysis Using RIVUR and CUTIE Data.

PURPOSE: The initial imaging approach to children with urinary tract infection (UTI) is controversial. Along with renal/bladder ultrasound, some advocate voiding cystourethrogram (VCUG), ie a bottom-up approach, while others advocate dimercaptosuccinic acid (DMSA) scan, ie a top-down approach. Comparison of these approaches is challenging. In the RIVUR/CUTIE trials, however, all subjects underwent both VCUG and DMSA scan. Our objective was to perform a comparative effectiveness analysis of the bottom-up vs top-down approach. MATERIALS AND METHODS: We simulated 1,000 hypothetical sets of 500 children using RIVUR/CUTIE data. In the top-down approach, patients underwent initial DMSA scan, and only those with renal scarring underwent VCUG. In the bottom-up approach, the initial study was VCUG. We assumed all children with vesicoureteral reflux (VUR) received continuous antibiotic prophylaxis (CAP). Outcomes included recurrent UTI, number of VCUGs and CAP exposure. We assumed a 25% VUR prevalence in children with initial UTI with sensitivity analysis using 40% VUR prevalence. RESULTS: Median age of the original RIVUR/CUTIE cohort was 12 months. First DMSA scan was performed at a median of 8.2 weeks (IQR 5-11.8) after the index UTI. In the simulated cohort, slightly higher yet statistically significantly recurrent UTI was associated with the top-down compared with the bottom-up approach (24.4% vs 18.0%, p=0.045). On the other hand, the bottom-up approach resulted in more VCUG (100% vs 2.4%, p <0.001). Top-down resulted in fewer CAP-exposed patients (25% vs 0.4%, p <0.001) and lower overall CAP exposure (5 vs 162 days/person, p <0.001). Sensitivity analysis was performed with 40% VUR prevalence with similar results. CONCLUSIONS: The top-down approach was associated with slightly higher recurrent UTI. Compared to the bottom-up approach, it significantly reduced the need for VCUG and CAP.

Selecting Children with Vesicoureteral Reflux Who are Most Likely to Benefit from Antibiotic Prophylaxis: Application of Machine Learning to RIVUR.

PURPOSE: Continuous antibiotic prophylaxis reduces the risk of recurrent urinary tract infection by 50% in children with vesicoureteral reflux. However, there may be subgroups in whom continuous antibiotic prophylaxis could be used more selectively. We sought to develop a machine learning model to identify such subgroups. MATERIALS AND METHODS: We used RIVUR data, randomly split into train/test in a 4:1 ratio. Two models were developed to predict recurrent urinary tract infection risk in scenario with and without continuous antibiotic prophylaxis. The test set was then used to validate recurrent urinary tract infection events and the effectiveness of continuous antibiotic prophylaxis. Predicted probabilities of recurrent urinary tract infection were generated from each model. Continuous antibiotic prophylaxis was assigned at various cutoffs of recurrent urinary tract infection risk reduction to evaluate continuous antibiotic prophylaxis effectiveness. RESULTS: A total of 607 patients (558 female/49 male, median age 12 months) were included. Predictors included vesicoureteral reflux grade, serum creatinine, race/gender, prior urinary tract infection symptoms (fever/dysuria) and weight percentiles. The AUC of the prediction model of recurrent urinary tract infection (continuous antibiotic prophylaxis/placebo) was 0.82 (95% CI 0.74-0.87). Using 10% recurrent urinary tract infection risk reduction cutoff, minimal recurrent urinary tract infection per population level can be achieved by giving continuous antibiotic prophylaxis to 40% of patients with vesicoureteral reflux instead of everyone. In a test set (121), 51 patients had continuous antibiotic prophylaxis randomization consistent with model recommendation (continuous antibiotic prophylaxis if recurrent urinary tract infection risk reduction >10%). Recurrent urinary tract infection incidence was significantly lower among this group compared to those whose continuous antibiotic prophylaxis assignment differed from model suggestion (7.5% vs 19.4%, p=0.037). CONCLUSIONS: Our predictive model identifies patients with vesicoureteral reflux who are more likely to benefit from continuous antibiotic prophylaxis, which would allow more selective, personalized use of continuous antibiotic prophylaxis with maximal benefit, while minimizing use in those with least need.

Changes in Clinical Presentation and Renal Outcomes among Children with Febrile Urinary Tract Infection: 2005 vs 2015.

PURPOSE: Recent studies have demonstrated trends of decreasing voiding cystourethrogram utilization rates and delayed vesicoureteral reflux diagnosis in some children. It is possible that such delays could lead to more children sustaining repeated episodes of febrile urinary tract infection, and potential kidney injury, prior to diagnosis and treatment. MATERIALS AND METHODS: Using single institutional, cross-sectional cohorts of patients in 2 time periods (2005 and 2015), we compared clinical presentation and renal outcomes among patients 13 years and younger with history of febrile urinary tract infection presenting for initial voiding cystourethrogram. Outcomes included 1) recurrent urinary tract infection, 2) presence of vesicoureteral reflux, 3) grade of vesicoureteral reflux, and 4) renal scarring. Associations between year of presentation and outcomes of recurrent urinary tract infection and vesicoureteral reflux diagnosis were evaluated using multivariable logistic regression models. For the outcome of renal scarring, a logistic regression model was fitted for propensity score matched cohorts. RESULTS: Compared to children presenting in 2005, those in 2015 had 3 times the odds of recurrent urinary tract infection (OR 3.01, 95% CI 2.18-4.16, p <0.0001). Time period was not associated with the odds of vesicoureteral reflux (OR 0.98, 95% CI 0.77-1.23, p=0.85). Those in 2015 were more likely to present with vesicoureteral reflux grade >3 (OR 2.22, 95% CI 1.13-4.34, p=0.02) but not vesicoureteral reflux grade >2 (OR 1.11, 95% CI 0.74-1.67, p=0.60). Renal scarring was more common among children presenting in 2015 (OR 2.9, 95% CI 1.03-8.20, p=0.04). CONCLUSIONS: Compared to 2005, children presenting in 2015 for post-urinary tract infection voiding cystourethrogram have increased likelihood of recurrent urinary tract infection and renal scarring, despite similar likelihood of vesicoureteral reflux diagnosis.

Antireflux Surgery at National Surgical Quality Improvement Program-Pediatric Hospitals.

PURPOSE: This study aims to examine contemporary practice patterns and compare short-term outcomes for vesicoureteral reflux procedures (ureteral reimplant/endoscopic injection) using National Surgical Quality Improvement Program-Pediatric data. MATERIALS AND METHODS: Procedure-specific variables for antireflux surgery were developed to capture data not typically collected in National Surgical Quality Improvement Program-Pediatric (eg vesicoureteral reflux grade, urine cultures, 31-60-day followup). Descriptive statistics were performed, and logistic regression assessed associations between patient/procedural factors and outcomes (urinary tract infection, readmissions, unplanned procedures). RESULTS: In total, 2,842 patients (median age 4 years; 76% female; 68% open reimplant, 6% minimally invasive reimplant, 25% endoscopic injection) had procedure-specific variables collected from July 2016 through June 2018. Among 88 hospitals, a median of 24.5 procedures/study period were performed (range 1-148); 95% performed ≥1 open reimplant, 30% ≥1 minimally invasive reimplant, and 70% ≥1 endoscopic injection, with variability by hospital. Two-thirds of patients had urine cultures sent preoperatively, and 76% were discharged on antibiotics. Outcomes at 30 days included emergency department visits (10%), readmissions (4%), urinary tract infections (3%), and unplanned procedures (2%). Over half of patients (55%) had optional 31-60-day followup, with additional outcomes (particularly urinary tract infections) noted. Patients undergoing reimplant were younger, had higher reflux grades, and more postoperative occurrences than patients undergoing endoscopic injections. CONCLUSIONS: Contemporary data indicate that open reimplant is still the most common antireflux procedure, but procedure distribution varies by hospital. Emergency department visits are common, but unplanned procedures are rare, particularly for endoscopic injection. These data provide basis for comparing short-term complications and developing standardized perioperative pathways for antireflux surgery.

Pattern recognition algorithm to identify detrusor overactivity on urodynamics.

AIMS: Detrusor overactivity (DO) of the bladder is a finding on urodynamic studies (UDS) that often correlates with lower urinary tract symptoms and drives management. However, UDS interpretation remains nonstandardized. We sought to develop a mathematical model to reliably identify DO in UDS. METHODS: We utilized UDS archive files for studies performed at our institution between 2013 and 2019. Raw tracings of vesical pressure, abdominal pressure, detrusor pressure, infused volume, and all annotations during UDS were obtained. Patients less than 1 year old, studies with calibration issues, or those with significant artifacts were excluded. In the training set, five representative DO patterns were identified. Candidate Pdet signal segments were matched to representative DO patterns. Manifold learning and dynamic time warping algorithms were used. Five-fold cross validation (CV) was used to evaluate the performance. RESULTS: A total of 799 UDS studies were included. The median age was 9 years (range, 1-33). There were 1,742 DO events that did not overlap with annotated artifacts (cough, cry, valsalva, movements). The AUC of the training sets from the five-fold CV was 0.84 ± 0.01. The five-fold CV leads to an overall accuracy 81.35%, and sensitivity and specificity of detecting DO events are 76.92% and 81.41%, respectively, in the testing set. CONCLUSIONS: Our predictive model using machine learning algorithms provides promising performance to facilitate automated identification of DO in UDS. This would allow for standardization and potentially more reliable UDS interpretation. Signal processing and machine learning interpretation of the other components of UDS are forthcoming.

Telemedicine for Pediatric Urological Postoperative Care is Safe, Convenient and Economical.

PURPOSE: We compared virtual visits, ie remote patient encounters, via a live video system, with conventional in-person visits with respect to clinical outcomes, family experience and costs in a pediatric urology surgical population. MATERIALS AND METHODS: Patients were enrolled in a prospective cohort study comparing postoperative virtual and in-person visits during a 4-month period in 2018. Appointment status and time metrics were tracked. The primary outcome was the safety of virtual visits, assessed by comparing the number of additional in-person visits, emergency department encounters and hospital readmissions. Secondary outcomes included the family assessment of the encounter and associated costs. After each visit families were prompted to complete a survey that assessed missed work/school and direct costs. Opportunity cost was estimated using reported missed work time, average national hourly wage and visit duration. RESULTS: Overall 107 virtual and 100 in-person postoperative visits were completed. There was no difference in patient characteristics, appointment compliance or clinical outcomes between the cohorts. Travel and waiting for care accounted for 98.4% of the total time spent for an in-person visit. With the virtual visit significantly less work and school were missed by parents and children, respectively. The opportunity costs associated with an in-person visit were computed at $23.75 per minute of face time with a physician, compared to $1.14 for a virtual visit. CONCLUSIONS: For pediatric postoperative care virtual visits are associated with shorter wait times, decreased missed work and school, and clinical outcomes similar to those of in-person visits. Telemedicine appears to reduce the costs associated with these brief but important encounters.

Interobserver Reliability of the Antenatal Consensus Classification System for Urinary Tract Dilatation.

OBJECTIVES: The consensus classification system for urinary tract dilatation (UTD) was designed to be more objective and reproducible than previously used systems. We sought to evaluate interobserver reliability of UTD components and overall scores in a prenatal population undergoing third-trimester ultrasound examinations. METHODS: We retrospectively identified patients who underwent antenatal ultrasound examinations for UTD between 28 and 40 weeks' gestation. All images from individual studies of 300 fetuses were reviewed independently by 5 experienced sonologists (1 maternal-fetal medicine specialist and 4 radiologists). Urinary tract dilatation scores (normal, A1, or A2/3) and Society for Fetal Urology (SFU) scores were assigned. Interobserver agreement between raters was evaluated with the Fleiss κ statistic. RESULTS: Overall interobserver agreement for the antenatal UTD risk score showed substantial agreement among all 5 readers (κ = 0.657 [95% confidence interval, 0.632, 0.683]; P < .001). All 5 readers applied the same UTD risk score in 53.7% of cases. Some variability in the antenatal UTD score and individual elements was observed. At least 2 UTD risk scores were assigned to a specific individual patient in 46.3% of cases (139 of 300), and all 3 UTD risk scores were assigned to a specific individual patient in 1.7% of cases (5 of 300). In 18.0% of cases (54 of 300), at least 2 readers assigned a UTD score different from that assigned by the other readers. Agreement was lowest for parenchymal appearance (κ = 0.225). Agreement for the SFU system was fair (κ = 0.368; P < .001). CONCLUSIONS: Interobserver agreement for the antenatal UTD grading system was substantial. Compared to the SFU system, the antenatal UTD system showed better agreement among readers.

Mutations in SLC26A1 Cause Nephrolithiasis.

Nephrolithiasis, a condition in which urinary supersaturation leads to stone formation in the urinary system, affects about 5%-10% of individuals worldwide at some point in their lifetime and results in significant medical costs and morbidity. To date, mutations in more than 30 genes have been described as being associated with nephrolithiasis, and these mutations explain about 15% of kidney stone cases, suggesting that additional nephrolithiasis-associated genes remain to be discovered. To identify additional genes whose mutations are linked to nephrolithiasis, we performed targeted next-generation sequencing of 18 hypothesized candidate genes in 348 unrelated individuals with kidney stones. We detected biallelic mutations in SLC26A1 (solute carrier family 26 member 1) in two unrelated individuals with calcium oxalate kidney stones. We show by immunofluorescence, immunoblotting, and glycosylation analysis that the variant protein mimicking p.Thr185Met has defects in protein folding or trafficking. In addition, by measuring anion exchange activity of SLC26A1, we demonstrate that all the identified mutations in SLC26A1 result in decreased transporter activity. Our data identify SLC26A1 mutations as causing a recessive Mendelian form of nephrolithiasis.

Why Does Prevention of Recurrent Urinary Tract Infection not Result in Less Renal Scarring? A Deeper Dive into the RIVUR Trial.

PURPOSE: The RIVUR (Randomized Intervention for Children with Vesicoureteral Reflux) trial reported that antibiotic prophylaxis reduced recurrent urinary tract infection but antibiotic prophylaxis was not associated with decreased new renal scarring. However, the original reports did not assess the relationship among recurrent urinary tract infection, new renal scarring and antibiotic prophylaxis in detail. Therefore, we investigated the relationship among these issues. MATERIALS AND METHODS: We included subjects with dimercaptosuccinic acid scan within 6 months of enrollment and at least 1 followup dimercaptosuccinic acid scan from the RIVUR trial. The primary outcome was recurrent urinary tract infection associated new renal scarring, defined as recurrent urinary tract infection and new changes on dimercaptosuccinic acid scan. Due to a low number of events, propensity score was used to adjust for confounders. Multivariate logistic regression was fitted to investigate the associations between the covariates and the outcome. RESULTS: A total of 489 patients (91% female, mean age 20.3 months) were included in the study. Any new renal scarring was more common among those with recurrent urinary tract infection (OR 4.1, 95% CI 2.0-8.5, p <0.01) after adjusting for age, sex, index urinary tract infection, duplication, bowel bladder dysfunction and antibiotic prophylaxis. Recurrent urinary tract infection associated new renal scarring occurred in 5 of 244 (2%) patients on antibiotic prophylaxis and 13 of 245 (5%) on placebo. Compared to antibiotic prophylaxis, placebo was associated with a higher risk of recurrent urinary tract infection associated new renal scarring (OR 3.1, 95% CI 1.0-8.8, p=0.04) after adjusting for age, sex, race, index urinary tract infection, bowel bladder dysfunction, duplication, hydronephrosis, vesicoureteral reflux grade and baseline renal scarring. There were no differences in scar severity at final dimercaptosuccinic acid scan (p=0.88) or change from baseline (p=0.53) between antibiotic prophylaxis and placebo. CONCLUSIONS: Recurrent urinary tract infection was associated with new renal scarring in the RIVUR trial. When limited to recurrent urinary tract infection associated new renal scarring, antibiotic prophylaxis was associated with a decreased risk of this outcome. It remains unclear why new renal scarring developed in a proportion of subjects without recurrent urinary tract infection. The results should be carefully interpreted due to the inherent limitations.

The Use of Telemedicine for the Postoperative Urological Care of Children: Results of a Pilot Program.

PURPOSE: For postoperative visits, which are often brief interactions between family and clinician, patients may prefer the convenience of receiving postoperative care from home. We evaluated the feasibility of telemedicine for postoperative encounters in pediatric urology. MATERIALS AND METHODS: We performed a prospective telemedicine pilot study during an implementation period from November 10, 2017 to March 22, 2018. All postoperative patients deemed eligible by 1 of 4 urologists were offered enrollment in the telemedicine program. Enrollees underwent at least 1 virtual visit within 6 weeks of surgery. Technical difficulties and the number of unscheduled visits and readmissions were noted. After each virtual evaluation the family and clinician were prompted to complete a survey pertaining to perceptions of the telemedicine experience, including how effective the virtual visit was in delivering care. For each virtual visit with a urologist we estimated roundtrip travel cost and time. RESULTS: There was 96% technical success when using the software. A total of 125 postoperative virtual visits were completed in 83 patients. Median age of the children was 3.4 years and 87% were boys. Clinicians found that the virtual visit was "very effective" in 86% of cases, delivering the same care that they would have provided during a visit in person. Families were estimated to have saved a mean $150 travel cost and a median of 113 minutes of travel time per visit. No adverse postoperative outcomes were observed. CONCLUSIONS: This pilot study demonstrates that telemedicine can be successfully implemented in the postoperative care of pediatric urology patients.

Interobserver and Intra-Observer Reliability of the Urinary Tract Dilation Classification System in Neonates: A Multicenter Study.

PURPOSE: The Urinary Tract Dilation classification system was designed to be more objective and reproducible than currently available grading systems. We evaluated the reliability and consistency of the system in newborns. MATERIALS AND METHODS: Of 1,046 infants 0 to 90 days old undergoing ultrasound for hydronephrosis 243 were randomly selected for study inclusion. Seven readers (4 radiologists and 3 urologists) at 4 institutions classified complete, de-identified ultrasound studies on a Web based platform. Interobserver and intra-observer agreement was evaluated using the Fleiss kappa statistic. RESULTS: Interobserver agreement for Urinary Tract Dilation risk score was moderate among the 7 readers (kappa = 0.421, 95% CI 0.404-0.438). Interobserver agreement using the Society for Fetal Urology scale was worse than with the Urinary Tract Dilation classification (kappa = 0.344, 95% CI 0.330-0.359). All 7 readers assigned the same Urinary Tract Dilation score in 19.3% of cases (47 of 243). In 38.7% of cases (94 of 243) at least 3 readers assigned a Urinary Tract Dilation score different from that assigned by the other readers. In 7% of cases (17 of 243) at least 3 readers assigned a score of P0/P1, while at least 3 readers scored the same cases as P2/P3. At least 3 different Urinary Tract Dilation risk scores were assigned to the same patient in 30.45% of patients (74 of 243). Among individual Urinary Tract Dilation elements calyceal dilatation and bladder status had the highest disagreement. Five readers regraded 80 cases and agreed with their previous Urinary Tract Dilation risk score in 63.8% to 75.0% of cases (kappa 0.458 to 0.729). CONCLUSIONS: Interobserver agreement using the Urinary Tract Dilation grading system is fair to moderate, with variable agreement on individual elements of the system. Agreement was higher for the Urinary Tract Dilation system compared to the Society for Fetal Urology scale.

Whole exome sequencing frequently detects a monogenic cause in early onset nephrolithiasis and nephrocalcinosis.

The incidence of nephrolithiasis continues to rise. Previously, we showed that a monogenic cause could be detected in 11.4% of individuals with adult-onset nephrolithiasis or nephrocalcinosis and in 16.7-20.8% of individuals with onset before 18 years of age, using gene panel sequencing of 30 genes known to cause nephrolithiasis/nephrocalcinosis. To overcome the limitations of panel sequencing, we utilized whole exome sequencing in 51 families, who presented before age 25 years with at least one renal stone or with a renal ultrasound finding of nephrocalcinosis to identify the underlying molecular genetic cause of disease. In 15 of 51 families, we detected a monogenic causative mutation by whole exome sequencing. A mutation in seven recessive genes (AGXT, ATP6V1B1, CLDN16, CLDN19, GRHPR, SLC3A1, SLC12A1), in one dominant gene (SLC9A3R1), and in one gene (SLC34A1) with both recessive and dominant inheritance was detected. Seven of the 19 different mutations were not previously described as disease-causing. In one family, a causative mutation in one of 117 genes that may represent phenocopies of nephrolithiasis-causing genes was detected. In nine of 15 families, the genetic diagnosis may have specific implications for stone management and prevention. Several factors that correlated with the higher detection rate in our cohort were younger age at onset of nephrolithiasis/nephrocalcinosis, presence of multiple affected members in a family, and presence of consanguinity. Thus, we established whole exome sequencing as an efficient approach toward a molecular genetic diagnosis in individuals with nephrolithiasis/nephrocalcinosis who manifest before age 25 years.

Advances in paediatric urology.

Paediatric urological surgery is often required for managing congenital and acquired disorders of the genitourinary system. In this Series paper, we highlight advances in the surgical management of six paediatric urological disorders. The management of vesicoureteral reflux is evolving, with advocacy ranging from a less interventional assessment and antimicrobial prophylaxis to surgery including endoscopic injection of a bulking agent and minimally invasive ureteric reimplantation. Evidence supports early orchidopexy to improve fertility and reduce malignancy in boys with undescended testes. A variety of surgical techniques have been developed for hypospadias, with excellent outcomes for distal but not proximal hypospadias. Pelvi-ureteric junction obstruction is mostly detected prenatally; indications for surgery have been refined with evidence, and minimally invasive pyeloplasty is now standard. The outlook for patients with neurogenic bladder has been transformed by a combination of clean intermittent catheterisation, algorithms of diagnostic investigations, and innovative medical and surgical therapies. Posterior urethral valves are associated with considerable mortality; fetal diagnosis allows stratification of candidates for intervention, but ongoing bladder dysfunction in patients after valve ablation remains a cause of long-term morbidity.