Fetal Urology Research Articles

Long-term surgical outcomes of ileovesicostomy at a single children's hospital

IntroductionThe ileovesicostomy (IV) is a surgical option for patients with refractory bladder dysfunction at-risk of upper tract deterioration who cannot catheterize or lack social support for managing an augmentation cystoplasty (AC). Long-term outcomes after IV in children are lacking in the literature. ObjectiveWe assessed the risk of long-term surgical complications in pediatric patients with IV at a single children’s hospital. Study designWe retrospectively reviewed the records of patients undergoing IV between 2002 to 2021 at a single children’s hospital. The primary outcome was the rate of surgical complications in IV patients after initial reconstruction. Specific complications of interest included intra-abdominal, reservoir, and stomal complications, respectively. We also assessed renal outcomes, including the change in glomerular filtration rate (ΔGFR) and Society of Fetal Urology (ΔSFU) hydronephrosis from the time of surgery to last follow up. ResultsThe study comprised 17 IV patients, with most patients having a diagnosis of spina bifida (65%). Median follow-up was 6.4 years. The mean rate of surgical complications per patient year was 0.11 +/- 0.20. On survival analysis, the time to first complication for IV was 84.4 months. The incidence of intra-abdominal, reservoir, and stomal complications over the study period was 2/17 (11.8%) for each of these complication types. The mean ΔSFU grade from the time of surgery to last follow up was -1.24 +/- 1.48 and mean ΔGFR was -2.5 +/- 32.7 ml/min. DiscussionWe found that IV in pediatric patients experience a low rate (0.11/year) of complications and that median time to first complication was 84 months. Additionally, IV offers adequate renal preservation. Our study is limited, though, by its retrospective nature, small sample size, heterogenous population and lack of comparison group. ConclusionOur experience demonstrates that IV has a low rate of surgical complications and preserves renal function. We believe it is a reasonable surgical option for the well selected patient with refractory bladder dysfunction at-risk of upper tract deterioration who is unable to reliably catheterize.

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.

Open distal ureteroureterostomy for non-refluxing duplicated collecting system in children: Multicentric study and mid-term outcomes

When indicated, ureteroceles and ectopic ureters in duplicated collecting systems can be managed via upper or lower urinary tract surgical approaches, or a combination of both. Open ureteroureterostomy (UU) has been described to address these conditions in the absence of lower pole (LP) vesicoureteral reflux (VUR). We report outcomes from multiple centers worldwide with mid-term follow-up. Our study consists of a retrospective review of records and imaging of children who underwent open distal UU via inguinal incision for duplicated collecting system without lower pole VUR in institutions from North America, South America, and the Caribbean. Descriptive statistics and univariate analysis were utilized. The records of 127 patients who underwent open distal UU for double collecting system between 2009 and 2022 were reviewed. Of those, 65% were female (n=82), with a mean age at operation of 18 months (range 3-180). Main presentation at surgery included prenatal hydronephrosis (64%, n=81), followed by febrile urinary tract infections (28%, n=36), and urinary incontinence or other (8%, n=10). The patients with antenatal or incidental diagnosis of hydronephrosis were classified as preoperative Society for Fetal Urology (SFU) grade 3 (n=64) and 4 (n=54) (96%). Those who were classified with SFU grade 0-2 (4%) had symptomatic clinical presentations including febrile urinary tract infections (UTIs) (n=3), urinary incontinence (n=3), and a 12-year-old patient with recurrent abdominal pain (n=1). Mean operative time from skin incision to skin closure was 86min (range 45-240). Mean hospital stay was estimated at 1.1 days (range 0.5-4). In our cohort of 127 patients, 3 (2%) developed Clavien-Dindo grade I (2 with ureteral stent displacement and 1 with a urine leak/managed conservatively), 6 (5%) with grade II (3 febrile and 3 non-febrile UTIs managed with oral antibiotics), and 2 (2%) with grade IIIb complications (urine leaks requiring surgical management), which were appropriately treated. None presented grade IV or V complications. A double J stent was used in 56 patients (44%), and a Penrose drain was left in 10 (8%). A total of 125 children (98%, n=125/127) showed sonographic improvement of hydronephrosis, or resolution of symptoms with stable ultrasound findings. Successful outcome was similar for both ureterocele and ectopic ureter subgroups: 49/49 patients with ureterocele showed 100% improvement, 76/78 children with ectopic ureter showed improvement in 97% of the cases. On univariate analysis, outcomes were similar regardless of the use of ureteral stents (p=0.11). Mean follow-up was 28.2 months (range 12-85). Open distal UU is a good alternative for the definitive surgical management of ectopic ureters and ureteroceles without LP VUR. This multicentric and mid-term follow-up study demonstrates that open distal UU offers high success rates, low morbidity, short operative times and hospital stays, and satisfactory aesthetic outcomes. Additionally, the surgery is performed extra-peritoneally and may not require the use of stents or drains, depending on surgeon preference. Further investigations are being conducted to determine the role of UU in the settings of double collecting systems associated with ipsilateral LP VUR.

Automated grading of prenatal hydronephrosis severity from segmented kidney ultrasounds using deep learning

Background and motivationsAntenatal or prenatal hydronephrosis (AHN) is a common kidney complication in unborn children. While AHN is generally benign and resolves over time, this condition can inflict serious kidney damage or even organ failure due to excessive waste accumulation in severe cases. Regardless of severity, AHN must be clinically monitored for resolution, with treatment plans and medications being revised according to updated prognoses. Kidney ultrasound images are one of the most common methods of monitoring AHN, but grading of this condition is highly subjective and clinicians may select inappropriate therapies or surgical interventions as a result. New approaches are required to differentiate subjects who can be managed without surgical intervention from those who require life-saving operations. MethodsAn end-to-end deep machine learning framework was developed to sequentially detect ultrasound regions of interest, segment kidneys from US images, and classify AHN severity. We propose the novel Kidney Ultrasound Segmentation Network (KUSNet) for kidney segmentation from ultrasound images, and the Prenatal Hydronephrosis Classification Network (PHCNet) for hydronephrosis severity stratification according to the Society of Fetal Urology (SFU) standards. The ground truth kidney masks were generated by two radiologists with more than five years of working experience while the SFU-based annotations for the AHN severity were done by two senior radiologists and three senior urologists with more than ten years of domain expertise. At each stage, the performance of the proposed models was assessed both quantitatively and qualitatively against state-of-the-art networks in the respective fields. ResultsThe proposed KUSNet for ultrasound kidney segmentation achieved 97.6% accuracy, 97.4% precision, 97.6% recall or sensitivity, 97.5% F1-score, 95.5% IoU or Jaccard score, and 92.1% Dice score, beating several state-of-the-arts. On the other hand, the novel PHCNet reached 93.9% accuracy, 93.7% precision, 93.9% recall, 93.8% specificity, and 89.0% F1-score subject-wise when performing multiclass stratification of AHN severity on segmented kidney regions. ConclusionArtificial intelligence-based tools can reliably classify AHN severity to reduce inter- and intra-observer bias, thereby aiding clinicians in the rapid selection of appropriate treatments and surgeries. Moreover, segmenting kidney regions beforehand significantly boosts AHN severity classification performance.

Analysis of outcomes of robot-assisted laparoscopic pyeloplasty in children from a tertiary pediatric center in South India.

This study aims to analyze the outcomes of robot-assisted laparoscopic pyeloplasty (RALP) in children with pelvi-ureteric junction obstruction (PUJO) over a 10-year period at a tertiary care center in South India. This study provides a detailed analysis of prospectively acquired data from 2013 to 2023 of all children who underwent RALP at our institution. Pre- and post-operative renal ultrasound and isotope renography were used to assess outcomes. Detailed information on patient demographics, procedural duration, post-operative pain relief, operation steps, and post-surgical follow-up protocols has been provided. The analysis included all patients who completed a 1-year follow-up. Between 2013 and 2023, 201 children underwent RALP. Of these, 185 children completed at least 1 year of follow-up and were included in the analysis. The mean age of the cohort was 4.9 years (1 month to 17 years), with males comprising the majority (77.3%). Twenty-five children (13.5%) were younger than 1 year of age. Left-sided PUJO was found to be more common. The mean console time was 76.5 min (40-180 min), and the average hospital stay was 2.8 days (2-5). After surgery, the mean reduction in antero-posterior diameter of the renal pelvis was more than 50% of its pre-operative value and statistically significant (3.3 ± 0.3 to 1.9 ± 0.9 cm). At the end of 1 year, the overall reduction in renal size was also significant (9.7 ± 2.3 cm pre-operative to 8.9 ± 1.8 cm post-operative). The pre-operative Society of Fetal Urology (SFU) grade of hydronephrosis was compared to the post-operative SFU grade, and the improvement (resolution/downgrading) was found to be statistically significant. The median split renal function in this series was 39% pre-operative and 43% post-operative, and the overall functional improvement after RALP was significant. A successful outcome was observed in 181 children (97.8%). Four children experienced persistent severe hydronephrosis and underwent redo stenting and/or redo pyeloplasty (2.1% failure rate). Post-operative complications, according to the Clavien-Dindo classification, were classified as type 1 in three children and type 3b in two children. There were no conversions to open surgery in the series. RALP emerges as the minimally invasive procedure of choice for children with PUJO at our institution. It is safe, delivering consistently excellent results and minimal complications. Our outcomes are comparable to those of previously published series. We trust that our experience will serve as a roadmap for those centers (especially in South Asia) embarking on a pediatric robotic program.

Objective sonographic measurements of renal pelvic diameter and renal parenchymal thickness can identify renal hypofunction and poor drainage in patients with antenatally detected unilateral ureteropelvic junction obstruction

INTRODUCTIONHydronephrosis grading systems risk stratify patients with potential ureteropelvic junction obstruction, but only some criteria are measured objectively. Most notably, there is no consensus definition of renal parenchymal thinning. OBJECTIVESThe objective of this study was to assess the association between sonographic measures of renal length, renal pelvic diameter, and renal parenchymal thickness and the outcomes of a)renal hypofunction(differential renal function{DRF} <40%) and b)high-risk renal drainage(T1/2 >40 minutes). STUDY DESIGNAn institutional database of patients who had diuretic renograms(DR) for unilateral hydronephrosis was reviewed. Only infants with Society for Fetal Urology(SFU) grades 3/4 hydronephrosis without hydroureter on postnatal sonogram and had a DR within 120 days were included. The following measurement variables were analyzed: anterior posterior renal pelvic diameter(APRPD), renal length(RL), renal parenchymal thickness(PT), minimal renal parenchymal thickness(MPT=shortest distance from mid-pole calyx to parenchymal edge), and renal pyramidal thickness(PyrT). RL, PT, MPT, PyrT measurements were expressed as ratios (hydronephrotic kidney/contralateral kidney). Multivariate logistic regression was performed for each outcome by comparing three separate renal measurement models. Model 1: RLR, APRPD, MPTR; Model 2: RLR, APRPD, PTR, Model 3: RLR, APRPD, PyrTR. Individual performance of variables from the best performing model were assessed via ROC curve analysis. RESULTS196 patients were included (107 with SFU grade 3, 89 with SFU grade 4) hydronephrosis. Median patient age was 29[IQR 16,47.2] days. 10% had hypofunction, and 20% had T1/2 >40 minutes. 90% with hypofunction and 87% with high-risk drainage had SFU4 hydronephrosis. Model 1 exhibited the best performance, but on multivariate analysis, only APRPD and MPTR were independently associated with both outcomes. No other measure of parenchymal thickness reached statistical significance. The odds of hypofunction and high-risk drainage increase 10% per 1mm increase in APRPD(aOR 1.1 [CI 1.03-1.2], p=0.005; aOR 1.1 [CI 1.03-1.2], p=0.003). For every 0.1unit increase in MPTR the odds of hypofunction decrease by 40%(aOR 0.6 [CI 0.4-0.9], p=0.019); and the odds of high-risk drainage decrease by 30%(aOR 0.7 [CI 0.5-0.9], p=0.011). Optimal statistical cut-points of APRPD >16mm and/or MPTR <0.36 identified patients at risk for obstructive parameters on DR. DISCUSSION AND CONCLUSIONOf the sonographic hydronephrosis measurement variables analyzed, only APRPD and MPTR were independently associated with objective definitions of obstruction based on renal function and drainage categories. Patients who maintain APRPD <16mm and/or MPTR >0.36 can potentially be monitored with renal sonograms as there is >90% chance that they will not have DRF<40% or T1/2>40 minutes.

Utility of ultrasound-based scoring system in post-pyeloplasty recovery.

Differentiation of uretero-pelvic junction obstruction (UPJO) from non-obstructive dilatation (NOD) is a major challenge. The aim of this retrospective study is to determine whether pyeloplasty prediction score (PPS) could predict the need for surgery and resolution after surgery. Among patients with antenatally diagnosed hydronephrosis, those who were stable during post-natal follow-up were considered NOD. The UPJO group were the ones who worsened and underwent pyeloplasty based on conventional indications. All patients with UPJO underwent laparoscopic dismembered pyeloplasty. PPS was determined based on three ultrasound parameters obtained retrospectively: Society of Fetal Urology (SFU) grade of hydronephrosis, transverse anteroposterior (APD), and the absolute percentage difference of ipsilateral and contralateral renal lengths. Among 137 patients included (R:L=59:73; M:F 102:35), 96 were conservatively managed (NOD), while 41 patients (29%) needed pyeloplasty (UPJO). Mean PPS was 4.2 (1.2) in the NOD group and it was significantly higher at 10.8 (1.63) in the UPJO group (p=0.001). All patients with PPS>8 needed a pyeloplasty, while two patients with PPS of 7 needed pyeloplasty due to drop in renal function. PPS cutoff value of >8 had a sensitivity 95%, specificity 100% and a likelihood ratio of 20. Post-pyeloplasty PPS resolution was proportional to the duration of follow-up. A PPS cutoff value of 8 or above is associated with the presence of significant UPJO. PPS is also useful in the assessment of hydronephrosis recovery post-pyeloplasty. The limitation of PPS: it can only be applied in the presence of contralateral normal kidney.

Doppler Ultrasound and Resistive Indices in the Diagnosis of Ureteropelvic Junction Obstruction in the Pediatric Population.

Mercapto acetyl tri-glycine renogram (MAG3) scan has been the gold standard assessment of pediatric ureteropelvic junction obstruction (UPJO) but requires intravenous access and radiation exposure. While Doppler ultrasound measurements of resistive indices (RI) of the arcuate arteries have been proposed as an alternative assessment of obstruction, they have not been widely adopted in the pediatric population. We hypothesized that RI of the main renal artery (RA) is more strongly correlated with MAG3 findings than arcuate RI. Pediatric patients with unilateral Society for Fetal Urology grade 3-4 hydronephrosis undergoing concomitant RUS and MAG3 were recruited. Doppler ultrasound peak systolic velocity (PSV); RI of bilateral RA at the origin, middle, and hilum; and RI of the superior, middle, and lower pole arcuate arteries were obtained. MAG3 differential renal function (DRF) and T½ were recorded. Differences in RI measurements (DRI) between the affected and normal kidney were calculated and compared with DRF and T½. 31 patients (median 4.6-month-old) were enrolled. Only RA RI at the origin differed between affected and normal kidneys (p < .001). DRI RA at the origin showed weak evidence for an association with MAG3 DRF < 40% (p .07). DRI was not associated with T½ > 20 minutes. There was weak evidence for an association between RA DRI at the origin and DRF but not with T½. These findings suggest that RA DRI may provide additional data in the evaluation of patients with UPJO to tailor the use of MAG3 and associated risk of radiation exposure to those patients most at risk for concomitant renal function impairment.

Does Age Influence the Functional Recovery after Infant Pyeloplasty?

The purpose was to study the correlation between age at surgery and functional recovery after infant pyeloplasty. All infants who underwent pyeloplasty were analyzed retrospectively in this multicenter study. Anteroposterior diameter (APD) >2 cm, split renal function (SRF) <40%, and Society of Fetal Urology (SFU) grade 3-4 were surgical indications. Based on the age at pyeloplasty, they were divided into Group 1 (1-3 months) and Group 2 (4-12 months). APD and SRF were compared before and after surgery in both groups. The fractional recoverable function (post-SRF-pre-SRF)/(50-pre-SRF) ×100 was correlated with age. Fifty-one infants underwent pyeloplasty (mean age: 1.6 months - Group 1 and 7.2 months - Group 2). The mean APD decreased from 3 cm to 1.2 cm in Group 1 while 2.8 cm to 2 cm in Group 2 (P = 0.001). The mean SRF increased from 32.28% to 42.81% in Group 1 while 31%-34.18% in Group 2. SRF recovery was significantly higher in Group 1 compared to Group 2 (P = 0.001). Regression analysis showed a weak negative correlation (r = -0.2792) between age at surgery and renal function improvement. Functional recovery after pyeloplasty is better when done earlier (1-3 months), as this gives the growing kidney the best opportunity to recover.

Area of hydronephrosis is a useful predictive factor of impacted ureteral stones.

Ureteroscopic lithotripsy for impacted stones is challenging, but it is important to predict impacted stones preoperatively. Hydronephrosis, which is evaluated by a grading system, is often apparent in impacted stones. However, the currently used grading system is a qualitative evaluation. We, therefore, focused on a quantitative evaluation: the area of hydronephrosis. The aim of this study was to investigate whether the area of hydronephrosis could predict impacted stones more accurately than Society for Fetal Urology grade. We retrospectively identified 160 patients who underwent ureteroscopic lithotripsy for ureteral stones at our hospital between January 2014 and April 2022. Impacted stones were defined as stones fixed to the ureteral wall that could not be moved by means of ureteroscopic manipulation or water pressure. Of the 160 patients, 54 (33.8%) had impacted stones. Comparing patient characteristics, there were significant differences in stone size, ureteral wall thickness, Society for Fetal Urology grade, renal pelvic width and area of hydronephrosis (all P < 0.01). Receiver operating characteristic analysis showed that area of hydronephrosis was the more significant predictive value (area under the curve 0.781) compared with Society for Fetal Urology grade (area under the curve 0.676, P < 0.01). Multivariate analysis revealed that significant independent predictive factors of impacted stones were thicker ureteral wall thickness and larger area of hydronephrosis (both P < 0.01). The area of hydronephrosis and ureteral wall thickness were significant predictors of impacted stones in patients undergoing ureteroscopic lithotripsy for ureteral stones. These factors may be useful for selecting the treatment and preoperative settings.

Retroperitoneoscopic Simple Nondismembered Pyeloplasty with Da Vinci Si Assistance to Prevent Alignment Shift.

Aims: Retroperitoneoscopic simple nondismembered pyeloplasty (SNDP) with da Vinci Si assistance was developed because of a possible risk for alignment shift after retroperitoneoscopic diamond-shaped bypass pyeloplasty (Diamond-Bypass; DP). Outcomes of SNDP and DP were compared. Materials and Methods: For SNDP, a small longitudinal incision is made on the border of the dilated pelvis and narrowed ureter at the ureteropelvic junction (UPJ). Extending this incision toward the pelvis allows identification of mucosa while maintaining the integrity of surrounding tissues that are so thin and fragile that they will not influence lumen alignment. Data for DP were obtained from a previously published article. Results: For SNDP (n = 3), mean age at surgery was 2.67 years (range: 1-4), mean operative time was 176 minutes. Mean postoperative Society of Fetal Urology (SFU) grades for hydronephrosis were 1.2, 0.7, and 0.6, 1, 2, and 3 months after stent removal, respectively. Postoperative diethylenetriaminepentaacetic acid (DTPA) was normal (n = 3). For DP (n = 5) mean age at surgery was 4.3 years (range: 1-14), mean operative time was 189 minutes. Mean postoperative SFU grades were 2.8, 2.2, and 1.6, respectively. Postoperative DTPA was normal (n = 4) and delayed (n = 1). All SNDP and DP were asymptomatic by 3 months after stent removal. Conclusion: Both SNDP and DP have favorable outcomes. If the UPJ is located at the lowest end of the renal pelvis, SNDP may improve hydronephrosis more quickly.

The Role of Varied Sonographic Criteria for Predicting Treatment and Prognosis of Antenatal Hydronephrosis: A Retrospective Cohort Study

Objective: This study aimed to compare the Society of Fetal Urology (SFU) guidelines, the anteroposterior pelvic diameter (APD), and the urinary tract dilation (UTD) classification criteria for predicting the prognosis of antenatal hydronephrosis (AH). Materials and Methods: This was a retrospective analysis of the relationship among the three classification criteria and their contribution to the diagnosis and prognosis of possible AH in a cohort of neonates. Results: This study was a retrospective review of 290 neonates. The mean age was 16.4 ± 9.0 days, and 33% of the study population comprised female babies. An image review demonstrated that 35% of the patients had severe vesicoureteral reflux (VUR), 22% exhibited severe obstruction, 40% had transient hydronephrosis, and 9% required surgery. The antenatal SFU grading criteria demonstrated a significant relationship with severe obstruction, and the postnatal SFU grading was related to the severity of VUR. The highest sensitivity for the presence of VUR for surgical intervention was obtained for prenatal SFU-1 (100%). The highest specificity was for prenatal SFU-4 (96%) for the presence of VUR, prenatal SFU-4 (99%), and postnatal SFU-4 (94%) for surgical intervention. Conclusion: No reliable sonographic findings were found to predict VUR or severe ureteropelvic junction obstruction. The SFU grading during the postnatal period may predict VUR with low sensitivity and specificity. However, all three classification criteria contributed to the evaluation of the need for treatment in this cohort.

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.

Non-refluxing Primary Megaureter in Children Resolves From Proximal to Distal

To evaluate a population of children with non-refluxing primary megaureter (NRPM), we investigated spontaneous resolution of ureteral dilation and the pattern (proximal to distal or distal to proximal) in which it occurs. From our prospectively collected prenatal hydronephrosis (HN) database (0-24months, 2008-2017), selecting those with NRPM (n=92). We excluded patients who underwent surgery (n=20), children with <6months follow-up (n=2) and without a voiding cystourethrogram (VCUG) (n=4). Images were segregated into 198 ureteric segments (proximal/mid/distal). We defined resolution as Society for Fetal Urology (SFU) (0/1), anteroposterior diameter (APD) <10mm, and ureteric dilatation <5mm. Descriptive statistics and Kaplan-Meier curves were created for time-to-resolution analyses. Of 66 patients and 198 ureteral segments, median age at presentation was 2months (0-12), 83% were male (33% circumcised). Mean APD at baseline was 11±4mm, and 79% had (SFU 3/4) HN. Mean dilatation of ureteral segments (mm) at baseline was: 9±2 proximal, 9±2 mid, and 11±3 distal. At a median follow-up time of 26 (7-83) months, dilation of 55 (83%) proximal, 48 (72%) mid, and 22 (33%) distal ureteric segments had resolved. Overall, HN resolution occurred in 76% of patients. Resolution rates were similar for proximal/mid-ureters (83% vs 72%; P=.20); however, they were significantly different from distal segments (83% proximal vs 33% distal; 72% mid vs 33% distal, P<.01). Our data suggest that spontaneous resolution of NRPM follows a proximal to distal progression. Distal ureteric dilatation takes up to 10months longer to resolve compared to that of proximal and mid-ureteric segments, as well as that of the renal pelvis.

Predicting obstruction risk using common ultrasonography parameters in paediatric hydronephrosis with machine learning.

To sensitively predict the risk of renal obstruction on diuretic renography using routine reported ultrasonography (US) findings, coupled with machine learning approaches, and determine safe criteria for deferral of diuretic renography. Patients from two institutions with isolated hydronephrosis who underwent a diuretic renogram within 3 months following renal US were included. Age, sex, and routinely reported US findings (laterality, kidney length, anteroposterior diameter, Society for Fetal Urology [SFU] grade) were abstracted. The drainage half-times were collected from renography and stratified as low risk (<20 min, primary outcome), intermediate risk (20-60 min), and high risk of obstruction (>60 min). A random Forest model was trained to classify obstruction risk, here named the 'Artificial intelligence Evaluation of Renogram Obstruction' (AERO). Model performance was determined by measuring area under the receiver-operating-characteristic curve (AUROC) and decision curve analysis. A total of 304 patients met the inclusion criteria, with a median (interquartile range) age of diuretic renogram at 4 (2-7) months. Of all patients, 48 (16%) were low risk, 102 (33%) were intermediate risk, 156 (51%) were high risk of obstruction based on diuretic renogram. The AERO achieved a binary AUROC of 0.84, multi-class AUROC of 0.74 that was superior to the SFU grade, and external validation (n = 64) binary AUROC of 0.76. The most important features for prediction included age, anteroposterior diameter, and SFU grade. We deployed our application in an easy-to-use application (https://sickkidsurology.shinyapps.io/AERO/). At a threshold probability of 30%, the AERO would allow 66 more patients per 1000 to safely avoid a renogram without missing significant obstruction compared to a strategy in which a renogram is routinely performed for SFU Grade ≥3. Coupled with machine learning, routine US findings can improve the criteria to determine in which children with isolated hydronephrosis a diuretic renogram can be safely avoided. Further optimisation and validation are required prior to implementation into clinical practice.

Automated Society of Fetal Urology (SFU) grading of hydronephrosis on ultrasound imaging using a convolutional neural network

Grading of hydronephrosis severity on postnatal renal ultrasound guides management decisions in antenatal hydronephrosis (ANH). Multiple systems exist to help standardize hydronephrosis grading, yet poor inter-observer reliability persists. Machine learning methods may provide tools to improve the efficiency and accuracy of hydronephrosis grading. To develop an automated convolutional neural network (CNN) model to classify hydronephrosis on renal ultrasound imaging according to the Society of Fetal Urology (SFU) system as potential clinical adjunct. A cross-sectional, single-institution cohort of postnatal renal ultrasounds with radiologist SFU grading from pediatric patients with and without hydronephrosis of stable severity was obtained. Imaging labels were used to automatedly select sagittal and transverse grey-scale renal images from all available studies from each patient. A VGG16 pre-trained ImageNet CNN model analyzed these preprocessed images. Three-fold stratified cross-validation was used to build and evaluate the model that was used to classify renal ultrasounds on a per patient basis into five classes based on the SFU system (normal, SFU I, SFU II, SFU III, or SFU IV). These predictions were compared to radiologist grading. Confusion matrices evaluated model performance. Gradient class activation mapping demonstrated imaging features driving model predictions. We identified 710 patients with 4659 postnatal renal ultrasound series. Per radiologist grading, 183 were normal, 157 were SFU I, 132 were SFU II, 100 were SFU III, and 138 were SFU IV. The machine learning model predicted hydronephrosis grade with 82.0% (95% CI: 75-83%) overall accuracy and classified 97.6% (95% CI: 95-98%) of the patients correctly or within one grade of the radiologist grade. The model classified 92.3% (95% CI: 86-95%) normal, 73.2% (95% CI: 69-76%) SFU I, 73.5% (95% CI: 67-75%) SFU II, 79.0% (95% CI: 73-82%) SFU III, and 88.4% (95% CI: 85-92%) SFU IV patients accurately. Gradient class activation mapping demonstrated that the ultrasound appearance of the renal collecting system drove the model's predictions. The CNN-based model classified hydronephrosis on renal ultrasounds automatically and accurately based on the expected imaging features in the SFU system. Compared to prior studies, the model functioned more automatically with greater accuracy. Limitations include the retrospective, relatively small cohort, and averaging across multiple imaging studies per patient. An automated CNN-based system classified hydronephrosis on renal ultrasounds according to the SFU system with promising accuracy based on appropriate imaging features. These findings suggest a possible adjunctive role for machine learning systems in the grading of ANH.

Predictors of surgical intervention for antenatally detected ureteropelvic junction obstruction (UPJO): A prospective multivariate analysis.

We aimed to identify clinical and radiological predictors of the need for surgical intervention in infants with antenatally detected UPJO. We prospectively followed infants born with antenatally diagnosed ureteropelvic junction obstruction (UPJO) presented at our outpatient clinics for evidence of obstructive injury with a standard protocol with ultrasonography and renal scintigraphy. Indications for surgery included progression of hydronephrosis on serial examinations, initial differential renal function (DFR) ⩽35% or >5% loss in sequential studies, and febrile urinary tract infection (UTI). Univariate and multivariate analyses were utilized to define the predictors for surgical intervention, while the appropriate cut-off value of the initial Anteroposterior diameter (APD) was determined using the receiver operator curve analysis. Univariate analysis revealed a significant association between surgery, the initial APD, cortical thickness, Society for Fetal Urology grade, UTD risk group, initial DRF, and febrile UTI (p-value < 0.05). No significant association between surgery and sex or side of the affected kidney (p-value 0.91 and 0.38, respectively). On multivariate analysis, the initial APD, initial DRF, obstructed renographic curve, and febrile UTI (p-value < 0.05) were the only independent predictors for surgical intervention. An initial APD of 23 mm can predict surgical requirement, with a specificity of 95% and sensitivity of 70%. For antenatally diagnosed UPJO, the APD value (at the age of 1 week), DFR value (at the age of 6-8 weeks), and febrile UTI during follow-up are significant and independent predictors of the need for surgical intervention. APD, when used with a cut-off value of 23 mm, is associated with high specificity and sensitivity for predicting surgical need.

THE RELATIONSHIP BETWEEN THE SIZE AND LOCALIZATION OF THE URETERAL STONE AND THE DEGREE OF HYDRONEPHROSIS

The aim of our research is to evaluate whether there is a relationship between the degree of hydronephrosis and, the size and location of the stones in the ureter in patients with ureteral stones, with computed tomography (CT). 105 patients who applied to Malatya Training and Research Hospital with the complaint of renal colic and underwent CT scan were included in the study. Hydronephrosis was evaluated by using the system developed by the Society of Fetal Urology. Stone sizes were grouped as &amp;lt;5 mm, 5 – 10 mm, and ≥ 10 mm. The location of the stones were indicated as proximal - middle - distal according to the anatomical parts of the ureters. 61 (58.1%) patients had stones in the distal ureter, 20 (19%) had stones in the middle ureter, and 24 (22.9%) had stones in the proximal ureter. It was determined that the stone size showed significant difference according to the degree of hydronephrosis (p&amp;lt;0.05). There was no significant relationship between the stone location being in the proximal, middle or distal parts of the ureter and the degree of hydronephrosis (p=0.241). While, as the size of ureteral stones increases the degree of hydronephrosis increases, there is no relation with the location of the stone and hydronephrosis.

Robot-Assisted Retroperitoneoscopic Diamond Bypass Pyeloplasty

AimRobot (da Vinci Si; Intuitive Surgical, Sunnyvale, CA) assisted retroperitoneoscopic diamond bypass pyeloplasty (R-RDBP) performed for ureteropelvic junction (UPJ) obstruction (n = 5) is presented. MethodsPatients were placed affected side up and the retroperitoneal space accessed conventionally using 3–4 trocars. The diamond-shaped anastomosis involved incising the lowest part of the renal pelvis 12–15 mm transversely and the ureter distal to the obstruction 10–12 mm longitudinally. The first two sutures were placed retroperitoneoscopically; one from the mid-caudal line of the renal pelvis to the apex of the ureteric incision (the apex of the diamond) and the other from the corner of the incision in the renal pelvis to halfway along the ureteric incision. Trocars were replaced and the robot system docked. The first robot suture was placed between these two sutures, and the anastomosis completed by suturing from posterior to ventral applying minimal tension to keep the anastomosis close to the renal pelvis. All sutures were interrupted absorbable 5-0 monofilament. ResultsMean age at R-RDBP was 4.3 (range: 1–14) years old. Height/weight were average. Preoperative Society for Fetal Urology (SFU) grading was 4.0 in all cases. All repairs were primary and progressed smoothly without perioperative complications; 3/5 had improved appetite postoperatively. Mean SFU grades 1–3 months postoperatively were 2.8, 2.2, and 1.6, respectively. Diuretic renography that was obstructive in all cases preoperatively was normal in four and delayed in one case, postoperatively. ConclusionR-RDBP prevented rotation/kinking of the ureter, enhanced precision of suturing, and maximized the diameter at the anastomosis, facilitating smooth urine flow. Level of EvidenceLEVEL IV.

Can Impaired Distal Ureteral Contraction Detected by Urinary Ultrasonography Indicate Presence of VUR?

Objective: The aim of this study was to determine if impaired distal ureteral contraction detected by urinary ultrasonography (US) could predict presence of vesicoureteral reflux (VUR). Materials and Methods: A Retrospective analysis of patients’ files between November 2016 and September 2020 was performed. A total of 248 children with demonstrated VUR on voiding cystourethrogram (VCUG) and who underwent urinary US within one week of the VCUG examination were included in the study. The degree of hydronephrosis was classified as per Society for Fetal Urology grading system and grading of VUR was done by the International Reflux Study Group grading system. The impaired distal ureteral contraction was defined as the reduced movement of the distal ureter as well as the deficiency of urine discharge into the bladder. Results: There was a significant correlation between the grade of VUR and the grade of hydronephrosis (p=0.0028). Also, the presence of distal ureteral dilation was related to increasing grades of VUR (p=0.001). The impaired distal ureteral contraction was present only in children with dilating VUR (grades III IV V) while its relationship between VUR grade was significantly high for grades IV and V VUR (p=0.001). Conclusion: In children, the impaired distal ureter contraction as well as the increase of grades of hydronephrosis, and the presence of distal ureteral dilation may aid decision-making in terms of requesting VCUG to detect dilating VUR.