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Introduction: 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 25 mm. 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., Methods: 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 (Figure A). 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., Results: 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 24 mm was the most sensitive cutoff value. The cutoff values ranged from 18 to 27 mm 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 24 mm for the supine extra-renal was similar for both grades., Conclusion: 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., (Copyright © 2022. Published by Elsevier Ltd.)

Introduction and Objective: The value of diuretic renography drainage times in congenital hydronephrosis (AHN) decision making is controversial. Recently, a group suggested a modification to the classically described diuretic drainage time cut-off values. They found that a drainage half-time (T 1/2 ) < 5 min was normal whereas a T 1/2 exceeding 75 min predicted pyeloplasty. In addition, they reported on the benefit of a delayed drainage image obtained with gravity assistance. We sought to evaluate the ability of these modified T1/2 criteria to predict pyeloplasty, alone or in combination with a delayed drainage image referred to as Global Washout (GWO)., Methods: We retrospectively reviewed 113 patients, including consecutive pyeloplasties for AHN from 2004 to 2018. Patients who underwent pyeloplasty due to low differential renal function (DRF) < 30% or infection were excluded. The control group comprised high grade AHN managed non-operatively. The initial renal ultrasound and MAG 3 Lasix renogram were reviewed for grade, differential renal function (DRF), T 1/2 and GWO. A ROC curve was used to evaluate the T 1/2 and GWO cut-off points that can predict pyeloplasty, using a p-value of less than 0.05., Results: The pyeloplasty group consisted of 62 patients and the control group consisted of 51 patients. Two patients (3%) in the pyeloplasty group had a T 1/2 < 5 min whereas 21 (34%) had T 1/2  > 75 min (p < 0.001). In the control group, 25 patients (49%) had T 1/2  < 5 min and none had T 1/2 >75 min (P < 0.001). The ROC curve for T 1/2 < 5 min demonstrated 94% sensitivity and 51% specificity whereas a T 1/2 >75 min demonstrated 100% specificity and 34% sensitivity. Analysis of the GWO using a ROC curve revealed that a cut-off of 50% GWO has 100% specificity and 52% sensitivity for pyeloplasty. Overall, a T1/2 > 75 min or GWO <50% predicted 53% of pyeloplasties (Fig A) and was absent in all conservatively managed cases., Discussion: The limitations of the present study include its retrospective nature. Secondly, the lack of a gold standard diagnostic test for uretero-pelvic junction obstruction hampers objective quantification of diagnostic test utility performance., Conclusions: We confirm the utility of the modified diuretic half-time criteria and delayed gravity assisted imaging. A T1/2 > 75 min or GWO <50% are indicators of severity whereas a T1/2 of <5 min or GWO >90% is reassuring. Gravity assisted delayed imaging can be especially helpful in cases with indeterminate T 1/2 times and should be included in the standard assessment of hydronephrotic kidneys. These parameters can be used to tailor the frequency and invasiveness of imaging within observation protocols., (Copyright © 2021. Published by Elsevier Ltd.)

Objectives: We evaluated the feasibility and value of renal pyramidal thickness (PT) as a predictor of pyeloplasty in high-grade postnatal hydronephrosis., Patients and Methods: We retrospectively reviewed the charts of patients who presented with postnatal hydronephrosis from 2008 to 2013. Included cases had grade 3 or 4 hydronephrosis. We included only units diagnosed as ureteropelvic junction obstruction. Gender, laterality, hydronephrosis side, renogram data, and follow-up data were recorded. Two investigators reviewed all patients' ultrasounds images. We measured PT and pelvic anteroposterior diameter (APD) in the last ultrasound before surgery. For those managed conservatively, measurements were obtained from the ultrasound with worst hydronephrosis. PT was measured in supine position in the middle third of the sagittal plane (Figure). We assessed the reliability of PT measurement using the intraclass correlation coefficient (ICC). Univariate and multivariate analyses were used to correlate the collected parameters to pyeloplasty incidence. Receiver operating characteristic curve was used to evaluate the cutoff value of PT that predicts pyeloplasty., Results: The total included cases were 155 patients (165 units). One hundred and fourteen units had grade 3 hydronephrosis and 51 units had grade 4 hydronephrosis. Fifty-two cases (55 units) underwent pyeloplasty. The median follow-up period was 37.6 months. PT measurement was reliable (ICC = 0.94). Univariate analysis revealed that SFU grading, APD, PT, T1/2, and MAG-3 curves were associated with surgery. Multivariate analysis showed that PT was a single independent predictor for pyeloplasty. PT ≤ 3 mm had 98.1% sensitivity and 89.7% specificity in predicting pyeloplasty., Discussion: PT is the first portion of renal parenchyma that is affected in high-grade hydronephrosis. Moreover, it changes little over the first 9 years of life. PT measurement in hydronephrosis was not previously evaluated. We found that PT was easily measured in most kidneys with high negative predictive value. The PT value as an indicator for pyeloplasty should undergo extensive assessment by other institutions with different protocols., Conclusion: Being a slowly growing part of the parenchyma, PT can be a good measurable parameter to predict pyeloplasty. Measurement of PT in hydronephrosis is reliable. PT ≤ 3 mm can predict pyeloplasty with 98.1% sensitivity and 89.7% specificity., (Copyright © 2018 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Odd-skipped related 1 (Osr1) is a transcriptional repressor that plays critical roles in maintaining the mesenchymal stem cell population within the developing kidney. Here, we report that newborn pups with a heterozygous null mutation in Osr1 exhibit a 21% incidence of vesicoureteric reflux and have hydronephrosis and urinary tract duplications. Newborn pups have a short intravesical ureter, resulting in a less competent ureterovesical junction which arises from a delay in urinary tract development. We describe a new domain of Osr1 expression in the ureteral mesenchyme and within the developing bladder in the mouse. OSR1 was sequenced in 186 children with primary vesicoureteric reflux, and 17 have single nucleotide polymorphisms. Fifteen children have a common synonymous variant, rs12329305, one child has a rare nonsynonymous variant, rs3440471, and one child has a rare 5'-UTR variant, rs45535040 The impact of these SNPs is not clear; therefore, the role of OSR1 in human disease remains to be elucidated. Osr1 is a candidate gene implicated in the pathogenesis of vesicoureteric reflux and congenital abnormalities of the kidney and urinary tract in mice., (Copyright © 2017 the American Physiological Society.)

Introduction: Laparoscopic reconstructive surgery is associated with a steep learning curve related to the use of two-dimensional (2D) vision and rigid instruments. With the advent of robotic surgery, three-dimensional (3D) vision, and articulated instruments, this learning curve has been facilitated. We present a hybrid alternative to robotic surgery, using laparoscopy with 3D vision and articulated shears., Objective: To compare outcomes of children undergoing pyeloplasty using 3D laparoscopy with articulated instruments with those undergoing the same surgery using standard laparoscopy with 2D vision and rigid instruments., Study Design: Medical charts of 33 consecutive patients with ureteropelvic junction obstruction who underwent laparoscopic pyeloplasty by a single surgeon from 2006 to 2013 were reviewed in a retrospective manner. The current 3D cohort was compared with the previous 2D cohort. Data on age, weight, gender, side, operative time, dimension (2D = 19 patients, 3D = 8 patients), presence of a crossing vessel, length of hospital stay, and complication rate were compared between the two groups. Articulating shears were used for pelvotomy and spatulation of the ureter in the 3D group. Statistical tests included linear regression models and chi square tests for trends using STATA software., Results: Operative time per case was decreased by an average of 48 min in the group undergoing 3D laparoscopic pyeloplasty compared with the group undergoing 2D laparoscopic pyeloplasty (p = 0.02) (Figure). Complication rate and length of hospital stay were not significantly affected by the use of 3D laparoscopy., Discussion: These favorable results are in accordance with previous literature emphasizing the importance of 3D vision in faster and more precise execution of complex surgical maneuvers. The use of flexible instruments has also helped overcome the well-described delicate step of a dismembered pyeloplasty, namely the pelvotomy and ureteral spatulation. Limitations of this study are those inherent to the retrospective study design., Conclusion: The use of 3D vision endoscopy with articulating instruments blurs the distinction between current robotic-assisted and conventional laparoscopic technology, and provides a hybrid alternative deserving further attention., (Copyright © 2016 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Purpose: We assessed the reliability and validity of the Urinary Tract Dilation classification system as a new grading system for postnatal hydronephrosis., Materials and Methods: We retrospectively reviewed charts of patients who presented with hydronephrosis from 2008 to 2013. We included patients diagnosed prenatally and those with hydronephrosis discovered incidentally during the first year of life. We excluded cases involving urinary tract infection, neurogenic bladder and chromosomal anomalies, those associated with extraurinary congenital malformations and those with followup of less than 24 months without resolution. Hydronephrosis was graded postnatally using the Society for Fetal Urology system, and then the management protocol was chosen. All units were regraded using the Urinary Tract Dilation classification system and compared to the Society for Fetal Urology system to assess reliability. Univariate and multivariate analyses were performed to assess the validity of the Urinary Tract Dilation classification system in predicting hydronephrosis resolution and surgical intervention., Results: A total of 490 patients (730 renal units) were eligible to participate. The Urinary Tract Dilation classification system was reliable in the assessment of hydronephrosis (parallel forms 0.92). Hydronephrosis resolved in 357 units (49%), and 86 units (12%) were managed by surgical intervention. The remainder of renal units demonstrated stable or improved hydronephrosis. Multivariate analysis revealed that the likelihood of surgical intervention was predicted independently by Urinary Tract Dilation classification system risk group, while Society for Fetal Urology grades were predictive of likelihood of resolution., Conclusions: The Urinary Tract Dilation classification system is reliable for evaluation of postnatal hydronephrosis and is valid in predicting surgical intervention., (Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Purpose: We evaluated the relationship between bladder urine transforming growth factor-beta1 concentration and severity of hydronephrosis in newborns with unilateral prenatal hydronephrosis., Materials and Methods: We prospectively studied all newborns presenting with unilateral prenatal hydronephrosis between January 2005 and 2007. Patients with associated anomalies, vesicoureteral reflux, contralateral pathology or ipsilateral ureteral dilatation were excluded from study. Postnatal evaluation included voiding cystourethrography, renal ultrasonography and determination of bladder urine transforming growth factor-beta1 concentration. Diuretic renal scans were performed in patients with initial grade 3 or 4 hydronephrosis or increasing hydronephrosis during followup. Pyeloplasty was performed when a well tempered renogram showed an obstructive drainage curve with a half-time greater than 20 minutes and/or an obstructive washout curve pattern during the diuretic phase. Patients were analyzed in observational and surgical groups. We studied the longitudinal changes in bladder urine transforming growth factor-beta1 in each group and compared concentration levels in the first 3 months of life in both groups., Results: A total of 42 newborns were included. The observational group consisted of 31 patients followed for a mean of 14 +/- 6 months. During the first 3 months, from 3 to 12 months and in the second year of life mean ultrasound grade and bladder urine transforming growth factor-beta1 decreased from 2.3 to 1.7 to 1.2 (p <0.05) and from 11.5 to 8.6 to 6.1 pg/mmol creatinine (p <0.05), respectively. Pyeloplasty was performed in 11 patients at a mean age of 6 +/- 5 months. Mean followup was 7 +/- 5 months. In the first 3 months, preoperatively and at 3 to 12 months postoperatively mean ultrasound grade and bladder urine transforming growth factor-beta1 were 3.5, 4 and 3 (p >0.05), and 23, 29 (p >0.05) and 8 pg/mmol creatinine (p <0.003), respectively. Mean bladder urine transforming growth factor-beta1 levels in the first 3 months of life were 23 +/- 14 and 11.5 +/- 8 pg/mmol creatinine in the surgical and observational groups, respectively (p <0.001). Limiting comparison to the 23 patients with initial grades 3 and 4 hydronephrosis revealed levels of 23 +/- 14 and 13 +/- 9 pg/mmol creatinine in the surgical and observational groups, respectively (p <0.02). At a cutoff of 17 pg/mmol creatinine bladder urine transforming growth factor-beta1 in the first 3 months of life was 82% sensitive and 86% specific in predicting surgery., Conclusions: Bladder urine transforming growth factor-beta1 changes through time are associated with similar changes in hydronephrosis grade. Bladder urine transforming growth factor-beta1 in the first 3 months of life can predict the need for surgery in newborns with prenatal hydronephrosis.

Purpose: We examined the urodynamic and upper urinary tract changes in children with myelomeningocele treated conservatively through puberty at our institution between 1980 and 2006., Materials and Methods: A total of 40 patients were exclusively treated conservatively with or without anticholinergics and/or clean intermittent catheterization through puberty at our institution. The records of 37 patients (17 males and 20 females) were available for review and constituted the subject matter for our study. The neurological lesion was sacral in 4 patients, lumbosacral in 5, thoracic in 12 and lumbar in 16. Clinical evaluations, radiological imaging studies of the upper urinary tract and urodynamic studies were repeated every 6 to 12 months. Data were collected and comparisons were made with respect to prepubertal (age 10 years) and postpubertal (15) continence status, urodynamic parameters and upper urinary tract changes. Children spontaneously achieving urinary continence postpubertally were examined in a similar fashion as a separate subgroup. Continence was defined as a dry interval of 4 hours or more., Results: Of the 26 patients with urinary incontinence before puberty 12 (2 males and 10 females, 45%, p <0.003) achieved continence following puberty. Hydronephrosis remained stable in 4 patients, improved in 3 and was new onset in 3 (p >0.05). Vesicoureteral reflux persisted in 1 patient, resolved in 4 and was new onset in 1 (p >0.05). Total cystometric bladder capacity, maximum detrusor pressure and detrusor leak point pressure all increased significantly after puberty, from 277 +/- 82 to 487 +/- 140 ml, 45 +/- 17 to 54 +/- 20 cm H(2)O and 49 +/- 16 to 59 +/- 21 cm H2O, respectively. In patients achieving urinary continence following puberty total cystometric bladder capacity increased significantly from 284 +/- 58 to 473 +/- 93 ml (p <0.005). Maximum detrusor pressure and detrusor leak point pressure showed insignificant changes after puberty, increasing from 45 +/- 11 to 47 +/- 16 cm H2O and from 46 +/- 11 to 55 +/- 21 cm H2O, respectively., Conclusions: This study demonstrates that total cystometric bladder capacity, maximum detrusor pressure and detrusor leak point pressure increase significantly in patients with myelomeningocele following puberty. The increase in bladder capacity could be attributed to increasing bladder outlet resistance resulting from prostate gland enlargement in males and estrogenization in females. A significant number of patients spontaneously achieve continence at puberty, and continence becomes more likely when increased total cystometric bladder capacity is not associated with an increase in maximum detrusor pressure. Finally, no significant postpubertal upper urinary tract deterioration was observed in our series.