High-grade Hydronephrosis Research Articles

Spontaneous resolution of primary obstructive megaureter: Risk stratification and prediction based on early sonographic factors.

To describe and develop predictors for spontaneous resolution of primary obstructive megaureter (POM) from early ultrasound measures. Children referred to our institution between 2007 and 2023 for POM were reviewed. POM was defined as hydroureteronephrosis with ureteral dilatation >7mm. We excluded patients with other etiologies for upper tract dilatation. Resolution was defined as decrease in hydronephrosis to <10 mm anteroposterior diameter (APD) or SFU grade ≤ 2, or ≤7 mm in hydroureter. Patients were censored if they underwent surgical intervention or were lost-to-follow-up before documenting resolution. Kaplan-Meier curves were drawn to illustrate the cumulative resolution rate and determine univariate associations. Cox proportional hazards regression was performed to identify significant predictors for early resolution and concordance index (c-index) was calculated. A total of 159 patients were included, with a median index age of 2 months and a median follow-up of 30 months. Of these, 89 patients reached spontaneous resolution during monitoring and likelihood of surgical indication at 1-year from US was 30%. APD >15 mm, high-grade hydronephrosis, ureteral dilation >10 mm, and ureter tortuosity at presentation were associated with a lower likelihood of resolution for individual Kaplan-Meier curves. A Cox regression model trained on these predictors achieved an adjusted c-index of 0.68, and low APD remained associated with a higher likelihood of resolution. Early sonographic features in POM, specifically APD, are associated with the likelihood of spontaneous resolution. Patients with high-risk features at first ultrasound warrant closer follow-up.

Upper tract dilation is an independent risk factor for febrile UTI in children with primary vesicoureteral reflux

BackgroundChildren with vesicoureteral reflux (VUR), particularly high-grade VUR, are known to be at increased risk for urinary tract infection (UTI). Current guidelines highlight certain clinical factors in the management of children with VUR; however, the clinical utility of upper tract dilation in the setting of VUR remains unclear. ObjectiveThe purpose of this study is to evaluate risk factors for febrile UTI (fUTI) in children with primary VUR in a modern cohort with emphasis on upper tract dilation parameters, including hydronephrosis and hydroureter. MethodsA prospectively maintained database of children with VUR at a single academic institution from July 2013 to February 2023 was reviewed. Demographic and clinical data were included. Ultrasounds closest to initial VCUG were reviewed for upper tract dilation, including the presence of hydronephrosis, Society of Fetal Urology (SFU) hydronephrosis grade, presence of hydroureter, and anterior-posterior renal pelvic diameter (APRPD). The primary outcome of interest was the development of a fUTI after VUR diagnosis. Patients were censored after their first fUTI or after VUR surgery. ResultsA total of 235 children with primary VUR were evaluated, including 125 (53.2%) females and 110 (46.8%) males. The median age of VUR diagnosis was 10.8 months (IQR: 2.3-63.6 months). A total of 41 (17.4%) children developed a fUTI after VUR diagnosis with a median follow up of 2.3 years (IQR: 0.9-4.6 years). On univariate analysis, variables found to be associated with fUTI included age < 1 year at VUR diagnosis (p=0.021), female sex (p=0.013), high-grade VUR (p=0.024), APRPD ≥ 7 mm (p=0.007), high-grade hydronephrosis (p=0.004), presence of hydronephrosis (p=0.029), and hydroureter (p=0.008). In children with VUR and high-grade hydronephrosis, a larger APRPD was associated with higher fUTI rates (p=0.008). On multivariate analysis controlling for age, sex, and VUR grade, APRPD ≥ 7 mm (OR 2.8, p=0.009), high-grade hydronephrosis (OR 2.5, p=0.025), and presence of hydronephrosis (OR 2.3, p=0.049) were independent risk factors for fUTI. On multivariate models controlling for other upper tract dilation parameters, APRPD ≥ 7 mm was the most significant parameter associated with increased fUTI risk in primary VUR. ConclusionUpper tract dilation is a novel, independent risk factor for fUTI in children with primary VUR, with APRPD being the strongest predictor. Clinicians may consider upper tract dilation parameters in addition to age, sex, and VUR grade when individualizing care in children with primary VUR.

Correlation between renal sonographic measurements and differential renal function obtained from nuclear renography in children with unilateral hydronephrosis

Children with higher grades of hydronephrosis often undergo mercaptoacetyltriglycine nuclear renography scans (MAG3) to assess differential renal function (DRF) and drainage. Although MAG3 helps identify the potential need for pyeloplasty, its use incurs increased costs, radiation exposure, and stress for children and families. Several studies demonstrate pyramidal thickness (PT)≤3mm as a reliable predictive risk factor for pyeloplasty in children with a history of prenatal hydronephrosis. Our hypothesis was that renal sonographic measurements including PT and parenchymal thickness (ParT) correlate with DRF in children with high-grade unilateral hydronephrosis and may be used to better select the need and frequency of MAG3 scans in children at increased risk for diminished relative renal function. The objective of this project was to determine the correlation between sonographic renal measurements and DRF in patients with unilateral hydronephrosis, we assessed: 1) the correlation between PT, ParT, and the ratio of PT/ParT in hydronephrotic kidneys to DRF, 2) the correlation between the ratio of hydronephrotic PT/contralateral non-hydronephrotic PT and DRF, 3) the correlation between the ratio of hydronephrotic ParT/contralateral non-hydronephrotic ParT and DRF, and 4) the correlation between the ratio of (hydronephrotic PT/ParT)/(contralateral non-hydronephrotic PT/ParT) and DRF. We retrospectively reviewed 71 children with grades 3 or 4 unilateral hydronephrosis. Most patients presented with a history of prenatally detected hydronephrosis at median age (IQR) of 112 days (43-274). Measurements of PT and ParT were completed on 98 renal ultrasounds and DRF was collected from corresponding MAG3 scans. Threshold values were identified visually through scatterplots. Spearman's correlation coefficient and Fisher's p-values were calculated. Ratios of PT and ParT in hydronephrotic kidneys to contralateral non-hydronephrotic kidneys were positively correlated with DRF. Ratios of hydronephrotic PT/non-hydronephrotic PT>0.8 and hydronephrotic ParT/non-hydronephrotic ParT >0.7 occurred more frequently in patients with a DRF >40% (p=0.11 and p=0.001, respectively). A PT>3mm and ParT >5mm occurred significantly more frequently in patients with a DRF >40% (p=0.008 and p=0.006, respectively). Renal sonographic measurements including threshold values of PT>3mm, ParT > 5mm, ratio of hydronephrotic PT/contralateral non-hydronephrotic PT (>0.8), and ratio of hydronephrotic ParT/contralateral non-hydronephrotic ParT (>0.7) are good predictors of DRF >40% in unilateral high-grade hydronephrosis. These identified threshold values have potential utility in determining the need for nuclear renal scans in children with high-grade hydronephrosis.

Should a Refluxing Internal Diversion Be Considered a Temporizing Procedure? Extended Follow-Up and Outcomes After Side-to-Side Ureterovesicostomy for Primary Obstructive Megaureter in Young Children.

We describe long-term outcomes, including UTIs and need for reimplantation, after ureterovesicostomy (UV) as a lasting surgical procedure for children with primary obstructive megaureter (POM). Children referred to our institution between 2016 and 2023 who underwent refluxing UV were analyzed. POM was defined as hydroureteronephrosis with distal ureteral dilatation > 7 mm and a negative workup for other etiologies of hydronephrosis. We assessed for surgical outcomes, complications, rate of UTI, and improvement in upper tract dilatation. Statistical analyses assessed for change in hydronephrosis metrics over follow-up. Among 183 patients diagnosed with POM, 47 (24%) underwent UV. Median age of presentation, surgery, and follow-up was 2, 9, and 43 months, respectively. A total of 7 patients developed 30-day complications: Clavien-Dindo grade 1 in 2 (transient urinary retention) and grade 2 in 5 (UTIs). During monitoring 14 (30%) developed UTIs and 7 (15%) required ureteral reimplant or UV takedown. After surgery there was a significant decrease in the proportion of patients with high-grade hydronephrosis, anteroposterior renal pelvis diameter, and maximum ureteral dilatation. Refluxing UV is a safe alternative to cutaneous diversion in POM. Most patients had improvement in upper tract dilatation with an acceptable short-term complication rate and need for reoperation (in comparison to routine later reimplantation). Our experience suggests that monitoring alone after UV is feasible, and that selective subsequent reconstruction is a reasonable strategy.

The conundrum of high-grade hydronephrosis with non-obstructive drainage on diuretic renography

Patients with high grade hydronephrosis (HN) and non-obstructive drainage on mercaptoacetyltriglycine (MAG-3) diuretic renography (renal scans) can pose a dilemma for clinicians. Some patients may progress and require pyeloplasty; however, more clarity is needed on outcomes among these patients. Our primary objective was to predict which patients with high-grade HN and non-obstructive renal scan, (defined as T ½ time <20min) would experience resolution of HN. Our secondary objective was to determine predictors for surgical intervention. Patients with prenatally detected HN were prospectively enrolled from 7 centers from 2007 to 2022. Included patients had a renal scan with T ½<20min and Society for Fetal Urology (SFU) grade 3 or 4at last ultrasound (RBUS) prior to renal scan. Primary outcome was resolution of HN defined as SFU grade 1 and anterior posterior diameter of the renal pelvis (APD)<10mm on follow-up RBUS. Secondary outcome was pyeloplasty, comparing patients undergoing pyeloplasty with patients followed with serial imaging without resolution. Multivariable logistic regression was used for analysis. Of the total 2228 patients, 1311 had isolated HN, 338 patients had a renal scan and 129 met inclusion criteria. Median age at renal scan was 3.1 months, 77% were male and median follow-up was 35 months (IQR 20-49). We found that 22% (29/129) resolved, 42% of patients had pyeloplasty (54/129) and 36% had persistent HN that required follow-up (46/129). Univariate predictors of resolution were age≥3 months at time of renal scan (p=0.05), T ½ time≤5min (p=0.09), SFU grade 3 (p=0.0009), and APD<20mm (p=0.005). Upon multivariable analysis, SFU grade 3 (OR=4.14, 95% CI: 1.30-13.4, p=0.02) and APD<20mm (OR=6.62, 95% CI: 1.41-31.0, p=0.02) were significant predictors of resolution. In the analysis of decision for pyeloplasty, SFU grade 4 (OR=2.40, 95% CI: 1.01-5.71, p=0.04) and T ½ time on subsequent renal scan of ≥20min (OR=5.14, 95% CI: 1.54-17.1, p=0.008) were the significant predictors. Patients with high grade HN and reassuring renal scan can pose a significant challenge to clinical management. Our results help identify a specific candidate for observation with little risk for progression: the patient with SFU grade 3, APD under 20mm, T ½ of 5min or less who was 3 months or older at the time of renal scan. However, many patients may progress to surgery or do not fully resolve and require continued follow-up.

Long Term Follow-Up Of Patients With Nonrefluxing Hydronephrosis.

The aim of this study is to examine the long-term prognosis of children with ureteropelvic junction obstruction-like hydronephrosis (UPJO-like HN). The files of children with hydronephrosis (HN) were analyzed retrospectively. Patients with vesicoureteral reflux (VUR) and other genitourinary anomalies were excluded. The final status of the HN, the need for surgery, and urinary tract infection (UTI) frequency were evaluated. The study included 219 patients with 302 renal units (RU) with HN. Surgery rate was higher in RUs with larger kidney size and parenchymal thinning (p:<0.001 for both). Hydronephrosis resolved in 113 (40.2%) RUs, improved in 66 (23.3%), unchanged in 100 (35.5%) and worsened in 4 (1.4%). The frequency of recovery and improvement was found to be less in RUs with severe HN, large kidney size, and thin parenchyma. The UTI frequency was higher in severe HN group (12.2% vs 30.6% p:<0.001). Children with mild HN had an excellent prognosis. Although the majority of the patients with high-grade HN had also a good prognosis, it seems important to closely follow up patients with severe HN, increased kidney size, and accompanying parenchymal thinning. Clinicians should be aware of the increased frequency of UTIs in children with severe HN.

Medullary pyramid thickness: The optimal cut-off value associated with the need for pyeloplasty in infants

The medullary pyramid compresses during the early phases of severe hydronephrosis and represents a promising ultrasound metric for the diagnosis and surveillance of PUJ obstruction. The aim of this study was to define the optimal cut-off value and utility of medullary pyramid thickness (MPT) associated with the need for pyeloplasty in infants being followed up for hydronephrosis. A retrospective review was performed over a five-year period to identify patients that were under surveillance for hydronephrosis during infancy and underwent a MAG3 to monitor the possible need for pyeloplasty. Ultrasound images were retrospectively reviewed to measure the MPT of the affected kidney in a blinded fashion. The primary outcome measure was subsequent requirement for pyeloplasty before three years of age. The Mann-Whitney U Test was used to determine statistically significant differences in the minimum MPT between the infant group requiring pyeloplasty and the non-operative group. Receiver operating characteristic analysis was performed to determine the optimal cut-off value associated with the requirement for pyeloplasty. A total of 63 patient cases were included, of which 45 underwent pyeloplasty (70%). A significant difference was found in the median MPT measurement between the pyeloplasty and non-operative groups (1.7mm vs. 3.8mm, p<0.001). The optimal cut-off value of MPT associated with pyeloplasty was 3.4mm. An MPT threshold of ≤3.4mm conferred a sensitivity of 98%, specificity of 63%, positive predictive value of 86%, and negative predictive value of 92%. Thinning of the medullary pyramid is an important ultrasound sign of parenchymal deterioration in high-grade hydronephrosis. An optimal MPT cut-off value of ≤3.4mm is associated with subsequent pyeloplasty in infants. MPT should be considered in future studies addressing the diagnosis and surveillance of PUJ obstruction.

Outcome of Renal Function after Laparoscopic Pyeloplasty in Children with High-Grade Hydronephrosis

Introduction: This study aimed to analyze the changes in differential renal function (DRF) after laparoscopic pyeloplasty in children with high-grade hydronephrosis and factors influencing DRF improvement. Methods: We reviewed the clinical data of unilateral ureteropelvic junction obstruction (UPJO) patients with SFU grade IV who underwent laparoscopic pyeloplasty between February 2018 and October 2020. The patients were divided into two groups: DRF improvement ≥5% (group 1) and DRF improvement <5% (group 2). Preoperative, operative, and postoperative parameters were included in the statistical analysis in both groups. Results: A total of 29 patients with a median age of 6 months were included. The preoperative DRF in group 1 was significantly lower than that in group 2 (36.97 ± 8.47% vs. 45.19 ± 5.22%, p = 0.004). Logistic regression and receiver operating characteristic analysis showed the preoperative DRF was the predictor for renal function improvement after pyeloplasty (p = 0.021) and had a significant predictive value (p = 0.004). Conclusion: Nearly half of the patients with high-grade UPJO had improved renal function at 1 year follow-up after laparoscopic pyeloplasty. Preoperative DRF was a predictor of renal function improvement, and postoperative functional recovery was superior in children with lower preoperative DRF.

A comparison between asymptomatic and symptomatic ureteral stones

To investigate the characteristics and impact of asymptomatic (silent) ureteral stones on renal function and compare them with those of symptomatic stones. We retrospectively reviewed the medical records of 677 patients who underwent ureteroscopic lithotripsy or laparoscopic ureterolithotomy for ureteral stones between 2016 and 2020. Patients were divided into two groups according to the presence of recognizable symptoms. We investigated the characteristics and impact of silent stones on post-treatment renal function recovery and compared them with those of symptomatic stones. Among the 677 patients, 43 (6.4%) had asymptomatic ureteral stones, and 634 (93.6%) had symptomatic ureteral stones. Compared to symptomatic stones, asymptomatic stones were larger (11.4 mm vs. 9.6 mm, p = 0.003), more commonly present in the upper ureter (62.7% vs. 48.0%, p = 0.04), and more commonly associated with high-grade hydronephrosis (32.8% vs. 12.3%, p < 0.001); however, no difference in metabolite composition was observed between the two group of stone. In the asymptomatic stone group, the mean preoperative estimated glomerular filtration rate (eGFR) was 77.37 ± 23.54 mL/min/1.73 m2, and the mean postoperative eGFR indicated no significant improvement at 1 day, 7 days, 3 months, and 12 months (76.66 ± 21.45, 77.89 ± 20.87, 77.29 ± 22.22, and 76.71 ± 24.21 mL/min/1.73 m2, respectively; p = 0.567, p = 0.613, p = 0.924, and p = 0.202, respectively). In the symptomatic stone group, the mean preoperative eGFR was 78.17 ± 28.25 mL/min/1.73 m2; the mean postoperative eGFRs at 1 day, 7 days, 3 months, and 12 months were 81.24 ± 26.38, 86.16 ± 25.61, 89.11 ± 25.43, and 89.50 ± 26.01 mL/min/1.73 m2, respectively and demonstrated significant improvement (p = 0.002, p < 0.001, p < 0.001, and p < 0.001, respectively). Silent stones irreversibly impaired renal function, even after proper management. Therefore, active treatment strategies are required for all patients who are hesitant to receive treatment for silent stones because of their asymptomatic status to prevent permanent renal impairment.

The utility of renal medullary pyramidal thickness measurements on the first and second postnatal ultrasound in infants with congenital hydronephrosis

Prior studies with postnatal ultrasound measurements of the medullary pyramid thickness (PT) demonstrate a PT<3mm as a significant risk factor for the diagnosis of UPJ obstruction and pyeloplasty. These studies used the postnatal ultrasound demonstrating the largest degree of hydronephrosis. Since early identification of children at increased risk of obstruction and pyeloplasty would be clinically useful, we reviewed the PT on the first and second postnatal ultrasound in infants with congenital hydronephrosis. The aims of the study were to determine the prognostic value of: 1) PT on the first and second postnatal ultrasound, 2) a change in PT between first and second ultrasounds, and 3) ratio of PT in the hydronephrotic kidney to the contralateral PT in the normal kidney in those with unilateral hydronephrosis. We hypothesized that a smaller PT on either the first or second ultrasound, as well as a decreasing PT between the first and second ultrasound, and a decreased ratio of hydronephrotic PT to the contralateral normal kidney, would each be early predictors of subsequent pyeloplasty. A retrospective chart and ultrasound review of children with a diagnosis of isolated high grade (SFU grade 3 or 4) hydronephrosis was performed. This study also analyzed the impact on predictive ability of the PT obtained on an ultrasound obtained before 3 days of life compared to those in which the first ultrasound was obtained after 3 days of life. 91 infants (77 boys and 14 girls) met eligibility criteria (105 kidneys). The median age (IQR) at first ultrasound was 1.5 (1.0-15.0) days and 54.0 (27.5-123.0) days at the second ultrasound. For the group overall, a smaller PT on both the first and second ultrasound was associated with increased risk of pyeloplasty, however, a PT obtained on an ultrasound prior to 3 days of life was not demonstrated to be predictive. Of note, PT was predictive in this same group of patients on their second ultrasound. A PT of <3mm on an ultrasound obtained beyond 3 days of life was associated with higher risk of pyeloplasty. The PT ratio of hydronephrotic to normal contralateral kidney of the children who had their first ultrasound after 3 days of life was also significant in predicting the odds of having surgery. In addition, a decreasing PT between the first and second ultrasound was also identified as a risk factor for pyeloplasty.

Ureterorenoscopic (URS) Lithotripsy and Balloon Dilation Cause Acute Kidney Injury and Distal Renal Tubule Damage: A Prospective Study.

Ureterorenoscopy (URS) is believed to be a safe and effective procedure for treating ureteral stones or ureteral strictures. Rapidly increasing intrarenal pressure during URS may have a negative impact on the kidney, but its effect on renal function is not well known. The aim of this study was to evaluate whether URS balloon dilation or lithotripsy could cause acute kidney injury (AKI), which was evaluated using urine neutrophil gelatinase-associated lipocalin (NGAL), and renal tubular damage, which was evaluated using urine α-glutathione S-transferase (GST) and πGST. This prospective study included 207 patients with a mean age of 53.8 years between September 2012 and June 2013. Four groups were included: the ureteral stricture group (group 1), the ureteral stone group (group 2), and two control groups. URS increased urine NGAL (uNGAL) levels on days 1 and 14 in both groups, and only elevated uGST levels were noted on day 14 after URS lithotripsy (URS). On day 14, the difference between low-grade and high-grade hydronephrosis was significant in group 1 (p < 0.001) compared to that in group 2 (p = 0.150). Multivariate logistic regression analysis revealed that age, baseline estimated glomerular filtration rate (eGFR), and stone size > 1.0 cm were associated with the complete recovery of hydronephrosis after URS on day 14. Patients with ureteral stones with preserved renal function had more AKI than those with impaired renal function. However, there was no significant difference in URS-related AKI between the ≤1 cm and >1 cm subgroups. In addition, urine αGST and πGST levels were both significantly higher in the stone > 1 cm subgroup than in the ≤1 cm subgroup. In conclusion, URS laser lithotripsy and balloon dilatation resulted in AKI and renal tubular damage on day 14, although post-URS double-J (DBJ) stenting was performed in every patient.

How can we measure the renal pelvic anteroposterior diameter in postnatal isolated hydronephrosis?

The anteroposterior diameter (APD) of the renal pelvis is a commonly used ultrasound parameter in the evaluation and management of hydronephrosis. It has been established that an APD value associated with pyeloplasty is around 25mm. Some believe the APD should be measured at the innermost part of the renal pelvis while others suggest that it should be done at the renal contour. However, there is no consensus on the optimal APD measurement technique including whether it should be measured supine or prone. This study compared six different techniques of APD measurements, in both supine and prone positions, and further evaluated their association with pyeloplasty. Data was obtained by retrospectively reviewing patients' charts that had initial high-grade hydronephrosis (HGH) from 2008 to 2014. We recorded the patients' demographics, ultrasound data and management choice. In the mid-renal transverse plane, the APD was measured by 2 blinded investigators, at the intra-renal, renal contour and extra-renal regions of the renal pelvis in supine and prone positions (FigureA). We compared the six APD measurements based on the outcome of management (pyeloplasty vs. conservative management). The ROC curve obtained was then used to assess the ability of various APD measurements in predicting surgical intervention. The cutoff value chosen that predicts pyeloplasty was the lowest diameter with 100% specificity. We included 129 patients (134 renal units). Forty-four renal units (42 patients) underwent pyeloplasty whereas 90 renal units (87 patients) were managed conservatively. Patients' demographics were grouped by both SFU grade and clinical outcome. Regardless of grade, the APD measurements were different in all 6 techniques. All APD measurement techniques showed good inter-rater reliability. Based on the ROC curve, all APD measurements were associated with pyeloplasty with an AUC from 0.89 to 0.91. The supine extra-renal APD measurement of 24mm was the most sensitive cutoff value. The cutoff values ranged from 18 to 27mm when including patients from all grades of hydronephrosis. The median APD measurements were significantly less for SFU grade 3 than grade 4 hydronephrosis in all positions (P<0.001 for all measurements), yet the predictive cutoff value of 24mm for the supine extra-renal was similar for both grades. APD measurements differ based on the technique, but they are all equally associated with the clinical outcome of pyeloplasty. The inter-rater reliability of all techniques were excellent. Though the median APD measurements are smaller in SFU grade 3, it appears that the cutoff for a predictive renal pelvic APD does not differ between SFU grades 3 and 4 for the supine extra-renal technique. We conclude that the technique for measuring the APD needs to be specified in studies of hydronephrosis and in any grading systems.

Home bladder pressure measurements correlate with urodynamic storage pressures and high-grade hydronephrosis in children with spina bifida

Patients with spina bifida are at risk for developing bladder and renal deterioration secondary to increased bladder storage pressures. To determine the association of home bladder volume and pressure measurements (home manometry) to: 1) detrusor storage pressures on urodynamics (UDS); and 2) the presence of Society of Fetal Urology (SFU) grades 3-4 hydronephrosis on renal bladder ultrasound in patients with spina bifida. Data were prospectively collected on patients with spina bifida and neurogenic bladder requiring clean intermittent catheterization. Patients used a ruler and typical catheterization equipment to measure bladder pressures and volumes at home. Home measurements were compared to UDS detrusor pressures and SFU hydronephrosis grade. Detrusor pressure <20cmH2O at 50% maximal cystometric capacity (MCC) on UDS was used as a measure of safe storage pressures on UDS; conversely, detrusor pressure >20cmH2O was used a measure to capture both unsafe storage pressures and those with potential for unsafe storage pressures. Receiver-operator characteristic curves and area under curve (AUC) were calculated to depict the association between home manometry variables with detrusor pressures on UDS and SFU grades 3-4 hydronephrosis. Included were 52 patients with a median age of 10.3 years (interquartile range 6.3-14.4 years). Three home manometry measurements (maximum bladder pressure, bladder pressure at maximum catheterized volume, and mean bladder pressure)>20cmH2O were sensitive for Pdet >20cmH2O at 50% MCC. Maximal bladder pressure >20cmH2O was the most sensitive among home manometry measures (sensitivity 100%, specificity 70%, AUC 0.92 for Pdet >20cmH2O at 50% MCC on UDS; sensitivity 100%, specificity 62%, AUC 0.89 for SFU grade 3-4 hydronephrosis). None of the patients who had maximum home bladder pressure <20cmH2O had SFU grades 3-4 hydronephrosis; conversely, individuals with maximal home bladder pressure >20cm had a wide range of hydronephrosis grades. None of the patients with maximal home bladder pressure <20cmH2O had grade 3-4 hydronephrosis. Home measurements of maximal bladder pressure, bladder pressure at maximum catheterized volume and mean bladder pressure of >20cmH2O were all sensitive for Pdet >20cmH2O at 50% MCC on UDS. Home manometry is an inexpensive and simple technique to identify patients at risk for and to monitor individuals at high risk of upper tract dilation, without incurring significant cost or morbidity.

Continuous antibiotic prophylaxis in isolated prenatal hydronephrosis

Prenatal hydronephrosis (PNH) is one of the most common congenital anomalies and can increase the risk of developing a urinary tract infection (UTI) in the first two years of life. Continuous antibiotic prophylaxis (CAP) has been recommended empirically to prevent UTI in children with PNH, but its use has been controversial. We describe the incidence of UTI in children with isolated PNH of the renal pelvis without ureteral dilation. Our objective was to compare patients receiving and not receiving CAP and determine whether CAP is beneficial at preventing UTI in children with isolated PNH. Children with confirmed PNH were enrolled between 2008 and 2020 into the Society for Fetal Urology Hydronephrosis Registry. Children with isolated dilation of the renal pelvis without ureteral or bladder abnormality were included. The primary outcome was development of a UTI, comparing patients who were prescribed and not prescribed CAP. In this cohort of 801 children, 76% were male, and 35% had high grade hydronephrosis (SFU grades 3-4). CAP was prescribed in 34% of children. The UTI rate among all children with isolated PNH was 4.2%. Independent predictors of UTI were female sex (HR=13, 95% CI: 3.8-40, p=0.0001), intact prepuce (HR=5.1, 95% CI: 1.4-18, p=0.01) and high grade hydronephrosis (HR=2.0, 95% CI: 0.99-4.0, p=0.05; Table) on multivariable analysis. For patients on CAP, the UTI rate was 4.0% compared to 4.3% without CAP (p=0.76). The risk of UTI during follow-up was not significantly different between patients who received CAP and patients who were not exposed to CAP; adjusting for sex, circumcision status and hydronephrosis grade (HR=0.72, 95% CI: 0.34-1.5, p=0.38). In sub-group analysis of patients at higher risk of UTI (uncircumcised males, females and high grade hydronephrosis), CAP use was not associated with a statistically significant reduction in UTI. The overall UTI rate in children with isolated PNH is very low at 4.2%. In the overall population of patients with isolated PNH, CAP was not associated with reduction in UTI risk, although the limitations in our study make characterizing CAP effectiveness difficult. Clinicians should consider risk factors prior to placing all patients with isolated PNH on CAP.

A pilot study assessing average detrusor pressure garnered from area under a urodynamic curve: Evaluation of clinical outcomes

The management of neurogenic bladder mostly relies on urodynamic studies; however, several studies have shown low interobserver reproducibility. The aim of this study was to evaluate if a new objective cystometric parameter was superior to other cystometric measures. A new parameter (pressure adjusted area under curve ratio, PAUC) was formulated from the ratio of area under the cystometry curve to a DLPP-adjusted total area (AT). AT was figured from a rectangle designed on the cystometrogram curve with a fixed height of 200 cmH2O and a width defined by the filling phase (figure). Two different estimated pressure measures derived from this (upper mean static pressure, UMSP and theoretical end filling pressure TEFP) were then calculated. Medical records of myelomeningocele patients with ultrasonography and renal scintigraphy performed at the time of urodynamics (with an interval of >5 years) were reviewed. Hydronephrosis and new scars in scintigraphy were used as the outcome measures. The study group consisted of 115 subjects with a median age of 4 (0-23) years at the time of the first urodynamic study. The median follow-up was 6 (5-14) years. PAUC and its derivatives (UMSP and TEFP) had the best discriminative power in predicting high grade hydronephrosis (0.830, 95% CI:0.732-0.927, p<0.001), worsening in hydronephrosis (0.827, 95% CI:0.723-0.931, p<0.001), and new scar formation (0.704, 95% CI: 0.576-0.832, p=0.002). PAUC>0.1 significantly correlated with urinary tract dilatation (p<0.001) and new scar formation (p=0.002). In the multivariate analysis, our three parameters and having scars at admission were the only independent risk factors for new scars (p=0.001 and p=0.002, respectively) and worsening in hydronephrosis (p<0.001 and p=0.001, respectively). Our results show that our three parameters derived from area under the urodynamic curve are more reliable than other urodynamic measures. Their major theoretical advantage is to incorporate all the pressure during filling phase giving a more accurate picture of what the intravesical pressure milleu is. Using these measures, we demonstrated their superiority in predicting clinical outcomes. Major limitations of this study are the retrospectively collected data and lack of longitudinal follow-up starting from infancy in each patient. Our new parameters (PAUC, UMSP and TEFP) which incorporate the impact of entire filling phase pressure changes in the analysis, may be useful tools to identify those patients who are under the risk of kidney damage with neurogenic lower urinary tract dysfunction.

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.

Comparison of retrograde intrarenal surgery and standard percutaneous nephrolithotomy for management of stones at ureteropelvic junction with high-grade hydronephrosis

Percutaneous nephrostomy (PCNL) and retrograde intrarenal surgery (RIRS) are the two main treatments for upper urinary tract stones. The aim of our study was to compare the effectiveness and safety of standard PCNL (S-PCNL) and RIRS for the treatment of stones at ureteropelvic junction with high-grade hydronephrosis. The study included 118 patients who underwent surgery for stones at ureteropelvic junction. S-PCNL and RIRS were performed on 66 and 52 patients, respectively. Patient age, sex, body mass index (BMI), stone side, history of urinary tract infection (UTI), history of diabetes, history of ESWL, stone size, Hounsfield unit (HU) values of stones, grade of hydronephrosis, operating time, postoperative hemoglobin loss, narcotic analgesic use, postoperative transfusion rates, stone-free rates (SFRs), length of hospital stay, complication rates and number of secondary interventions were recorded. The comparison of the operative data between the two groups revealed no statistically significant differences in the operative time, SFRs, narcotic analgesic use, postoperative transfusion rate or other postoperative complications defined according to the Clavien system (P > 0.05). The postoperative urinary sepsis rate in the RIRS group was as high as 15.4%, which was much higher than the 1.5% rate observed in the S-PCNL group, and the difference was statistically significant (P < 0.05). A total of 13.5% of the patients in the RIRS group required a second operation due to failure of the placement of the ureteral access sheath. Additionally, S-PCNL had an advantage in operation time, while RIRS in duration of hospital stay and postoperative hemoglobin loss. RIRS and S-PCNL were safe and effective methods for the treatment of stones at ureteropelvic junction with high-grade hydronephrosis. Importantly, S-PCNL had more advantages in terms of the postoperative urinary sepsis rate and secondary surgery rate.

Diagnostic accuracy of an interdisciplinary tertiary center evaluation in children referred for suspected congenital anomalies of the kidney and urinary tract on fetal ultrasound - a retrospective outcome analysis

BackgroundFetal ultrasound organ screening has become a standard of care in most high-income countries. This has resulted in increased detection of congenital abnormalities, which may lead to major uncertainty and anxiety in expectant parents, even though many of them are of minor relevance. In order to optimize prenatal counselling, we introduced an interdisciplinary approach for all pregnant women referred to our center by private obstetricians for a co-assessment of suspected relevant fetal abnormalities of the kidney or urinary tract, involving both experienced prenatal ultrasound specialists and a pediatric nephrologist or urologist.MethodsIn a retrospective analysis, we evaluated reports of intrauterine evaluation and postnatal follow-up in order to assess accuracy of explicit intrauterine diagnoses and outcome of hydronephroses according to their severity in this setting.ResultsA total of 175 fetuses were examined between 2012 and 2019 and followed postnatally at our Pediatric Nephrology or Urology Department. There was a high concordance (85.9%) between explicit intrauterine and final diagnoses. Resolution rate of hydronephrosis was higher in patients with intrauterine low-grade than high-grade hydronephrosis (61.8% versus 11.9%). An etiological diagnosis was found in 62.5%, 52.0%, and 11.1% of patients with intrauterine bilateral high-grade, unilateral high-grade, and unilateral high-grade with contralateral low-grade hydronephrosis, respectively, but in none of the patients with intrauterine low-grade hydronephrosis.ConclusionsThe results of our study demonstrate that, through interdisciplinary teamwork, intrauterine assessment of the fetal kidneys and urinary tract is highly accurate and allows a good discrimination between relevant and transient/physiological hydronephroses.Graphical abstractA higher resolution version of the Graphical abstract is available as Supplementary information

Needle Loss in Minimal Invasive Surgery Is a Real Challenge: Innovative Technique for Retrieval

Introduction: Intraoperative retained needles is reported to be ~0.06% to 0.11% with its consequence medical and ethical significance.1 Such small needles can be detached from the sutures and fly away from the limited laparoscopic vision or hidden between bowel loops that makes its localization and retrieval extremely difficult even in the hands of best experienced surgeons.2 However, intraoperative radiographic images maybe used in detecting lost needle; smallest needle <13 mm can be unhelpful.3 Kandioler-Eckersberger et al. reported two cases in which a novel laparoscopic magnetic retrieval device was utilized along with fluoroscopy in retrieval of broken fragments without the need to convert to open surgery.4 Herein, we demonstrate an innovative technique in retrieving a small suture needle that was lost during robotic pyeloplasty. Methods and Materials: This is a 7-year-old boy who was recently found to have left-sided pelviureteral junction obstruction after frequent emergency department visits with colicky abdominal pain. Ultrasonography and nuclear scans showed high-grade hydronephrosis with an obstructive curve; therefore, he was posted for robotic pyeloplasty. During the procedure and while doing the ureteropelvic anastomosis through 6/0 polydioxanone suture, the needle detached from the suture and was lost from the camera vision. At the end of the procedure, exploration of the abdominal cavity was accomplished through laparoscopic camera without the ability to detect the small needle. We used the retrieval device of the magnetic Double-J stent that consists of Tiemann-type with 15F diameter and magnet through one of the working ports and started to scan the abdominal cavity in systemic way under supervision of the laparoscopic camera. This magnetic retrieval device is semifixable that does not damage the intra-abdominal organs and has a strong magnetic power that can attach with metallic foreign bodies such needles efficiently. Results and Conclusion: The lost small needle was retrieved easily and safely without the need for conversion to open surgery or exposure to radiation. The innovative technique of using the magnetic retrieval device of Double-J stents as an intracorporeal laparoscopic device can be a valid and safe alternative in the retrieval of small metallic objects such as needles. Source of the study: A clinical case was encountered during practice. No competing financial interests exist. Runtime of video: 3 mins 54 secs

Diagnostic Test Characteristics of Ultrasound Based Hydronephrosis in Identifying Low Kidney Function in Young Patients with Spina Bifida: A Retrospective Cohort Study.

Kidney dysfunction in spina bifida is usually detected by low estimated glomerular filtration rate or ultrasound based hydronephrosis. We assessed the diagnostic test characteristics of hydronephrosis for detecting low estimated glomerular filtration rate, hypothesizing that hydronephrosis has low sensitivity compared to cystatin C based estimated glomerular filtration rate. We conducted a single center, retrospective cohort study, including patients with spina bifida from 2012-2017 with 2 kidneys and complete data needed to calculate estimated glomerular filtration rate via multiple pediatric (age 1-17.9 years) or adult (age ≥18 years) estimating equations. We evaluated the association of hydronephrosis status (high grade, low grade or none) with estimated glomerular filtration rate, adjusting for small kidney size and scarring, and calculated diagnostic test characteristics of hydronephrosis for low estimated glomerular filtration rate. We analyzed 247 patients (176 children and 71 adults). Mean±SD age was 13.7±6.6 years, and 81% of patients had myelomeningocele. Hydronephrosis (77% low grade) was found in 35/176 children and 18/71 adults. Hydronephrosis was associated with low estimated glomerular filtration rate in stepwise fashion, independent of kidney size and scarring. However, across cystatin C based pediatric equations, any hydronephrosis (compared to none) had 23%-48% sensitivity, and high grade hydronephrosis (compared to none or low grade) had 4%-15% sensitivity for estimated glomerular filtration rate <90 ml/min/1.73 m2, which remained unchanged after excluding small kidneys and scarring. Across cystatin C based adult equations, any and high grade hydronephrosis had 55%-75% and 40%-100% sensitivity, respectively, for estimated glomerular filtration rate <90 ml/min/1.73 m2, although with wide confidence intervals. Specificity was higher with high grade vs any hydronephrosis. Sensitivities were higher for estimated glomerular filtration rate <60 ml/min/1.73 m2. Hydronephrosis was associated with low estimated glomerular filtration rate but had poor sensitivity for cystatin C based estimated glomerular filtration rate <90 ml/min/1.73 m2, especially among children with spina bifida.