Hydronephrotic lower moiety of duplex systems: Observations using diuresis renography.

PURPOSE: The purpose of this study is to characterize the prevalence and behavior of hydronephrosis of non-refluxing lower moiety of duplex kidneys using MAG-3 diuresis renography. We compare our data to previous case series and ureteropelvic junction obstruction of single systems. MATERIALS AND METHODS: An IRB-approved database of over 5000 diuresis renograms performed in 2025 patients was queried to identify cases of hydronephrosis of lower moiety of duplex kidneys suspicious for ureteropelvic obstruction, excluding those with hydroureter or reflux. Kidney function and post-furosemide drainage parameters on initial and follow-up diuresis renograms were recorded. Medical records and patient outcomes were reviewed. RESULTS: In total, 19 renal units were identified in 18 patients (11 male, 7 female), age range 0.5 months to 17.8 years, including one patient with bilateral lower moiety hydronephrosis. Initial diuresis renograms in 12 asymptomatic patients (13 renal units) with antenatal hydronephrosis demonstrated varying drainage patterns from normal to obstructed. Follow-up studies showed worsening drainage in 3 patients, who all underwent surgery. Drainage improved in 4 patients and remained unchanged in 5 patients (6 renal units). Of the 6 patients presenting with Dietl's crisis, 5 showed obstructive drainage on initial diuresis renogram, 2/5 with decreased function. All 5 obstructed patients underwent surgery. CONCLUSION: Hydronephrosis of the lower moiety of a duplex system is rare and behaves similarly to single systems. The majority are diagnosed antenatally, display a dynamic nature, and may present with acute obstruction. Diuresis renography is a valuable tool in its evaluation and management.

Predictive role of ureteral wall thickness and patient characteristics in endoscopic treatment outcomes for ureteral stricture disease following stone surgery.

PURPOSE: To evaluate the role of certain radiological parameters and patient characteristics in predicting the success of endoscopic treatment in ureteral stricture disease. METHODS: Fifty one adult patients with ureteral stricture disease (< 1 cm) after developing due to upper ureteral stones with ureteroscopic laser disintegration were included and in addition to stone and patient parameters, radiological parameters including ureteral wall thickness (UWT) at the impacted stone site were also measured on computed tomography (CT) images. Patients were divided into two groups: Group 1: Patients with endoscopic treatment success and Group 2: Patients with endoscopic treatment failure. The possible relationship between the UWT values and other radiological parameter was comparatively evaluated. RESULTS: Mean UWT value assessed at the treated stone site was significantly higher in cases unresponsive to endoscopic treatment with values of 2.77 ± 1.03 mm and 4.25 ± 1.32 mm in Group 1 and 2 respectively. A cut off value 3.55 mm for UWT was found to be highly predictive for endoscopic treatment failure. CONCLUSIONS: Our current results indicated that assessment of UWT value at the obstructing stone could be helpful enough to predict the likelihood of failure following endoscopic management of strictures with high sensitivity and specificity. Evaluation of this particular parameter could let the endourologists to look for more rational treatment alternatives with necessary measures taken on time.

PET image-guided kidney injury theranostics enabled by a bipyramidal DNA framework.

Understanding the pharmacokinetic profiles of nanomaterials in living organisms is essential for their application in disease treatment. Bipyramidal DNA frameworks (BDFs) are a type of DNA nanomaterial that have shown prospects in the fields of molecular imaging and therapy. To serve as a reference for disease-related studies involving the BDF, we constructed a 68Ga-BDF and employed positron emission tomography (PET) imaging to establish its pharmacokinetic model in healthy mice. Our investigation revealed that the BDF was primarily eliminated from the body via the urinary system. Ureteral obstruction could significantly alter the metabolism of the urinary system. By utilizing the established pharmacokinetic model, we sensitively observed distinct imaging indicators in unilateral ureteral obstruction and acute kidney injury (a complication of ureteral obstruction) mouse models. Furthermore, we observed that the BDF showed therapeutic effects in an AKI model. We believe that the established pharmacokinetic model and unique renal excretion characteristics of the BDF will provide researchers with more information for studying kidney diseases.

Complications Subsequent to Urinary Tract Stent Placement: An Overview Focusing on the Imaging of Cancer Patients.

Ureteral involvement by a tumor is common, and both partial and complete obstructions can result in symptoms that are distressing and debilitating, especially in cancer patients for whom the resection of the primary tumor is not considered an option. Maintaining ureteric patency in these patients is a challenge. In addition, in cases where a patient has undergone nephroureterectomy due to primary transitional cell cancer, it becomes necessary to decompress the urinary tract to preserve the contralateral kidney from irreversible damage. This is possibly due to ureteral stenting, both retrograde and anterograde, and percutaneous nephrostomy (PCN). Since imaging plays an important role in the routine monitoring of stents, their more and more increasing use requires radiologists to be familiar with these devices, their correct position, their potential complications, and their consequences. The aim of this review is to offer a comprehensive review of the imaging features of some urinary stents and to show the complications encountered in cancer patients as a direct consequence of an invasive diagnostic or therapeutic procedure. Specifically, we focus on ureteral stents and PCN.

Intrinsic ureteric obstruction secondary to endometriosis: a rare clinical entity causing obstructive uropathy and renal failure.

Ureteral endometriosis is rare and can be a silent clinical entity, which can potentially lead to serious complications such as obstructive uropathy, sepsis and renal failure. A high clinical suspicion is required especially in childbearing age groups due to non-specific presentation such as renal colic, recurrent urinary tract infection (UTI), renal failure or asymptomatic hydronephrosis.A woman in her 40s presented with febrile UTI and flank pain. She reportedly suffered from recurrent UTIs in the past. Initial workup revealed an infected, obstructed left renal collecting system with gross hydronephrosis and hydroureter to the distal ureter on a significant gynaecological background of severe endometriosis requiring hysterectomy in the past.CT showed chronic obstructive changes and soft tissue nodules within the renal pelvis with no radio-opaque stones. She underwent emergent ureteric stent insertion. Functional imaging demonstrated only 1% contribution of the left kidney with a preserved estimated glomerular filtration rate of 65 mL/min/1.73 m2Endoscopic evaluation of ureters found extensive soft tissue lesions throughout the dilated left collecting system with biopsy-confirmed endometriosis. Subsequently, she underwent laparoscopic nephroureterectomy due to extensive ureteric involvement and chronically obstructed non-functioning kidney. Histopathology demonstrated completely obstructing ureteral endometriosis.Ureteric obstruction secondary to endometriosis can be due to extrinsic or intrinsic disease. In addition to initial assessment with CT urogram MRI may be helpful to evaluate soft tissue thickening. Endoscopic assessment with ureteroscopy and biopsy is required for tissue diagnosis. Surgery is often the treatment of choice, ranging from ureteroureterostomy, ureteroneocystostomy or nephroureterectomy in severe cases.Ureteral endometriosis is a rare clinical entity, clinicians should remain vigilant about common presentations of this rare entity, early diagnosis and prompt treatment is crucial to prevent progression to renal failure.

Percutaneous Nephroureteral Stent Placement and Antegrade Forceps Biopsy of Ureteral Obstruction.

PURPOSE: To evaluate the feasibility of percutaneous transluminal ureteral biopsy (PTUB) combined with percutaneous nephroureteral stent placement for ureteral obstruction under fluoroscopy. MATERIALS AND METHODS: From September 2011 to July 2021, 37 patients (27 men and 10 women; median age, 65.0 years) who experienced ureteroscopic biopsy failure or refused or were unable to undergo ureteroscopic biopsy underwent PTUB for ureteral obstruction during nephroureteral stent placement under fluoroscopic guidance. Data on technical success, early adverse events, and radiation dose were collected. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy (OA) of PTUB were analyzed. RESULTS: The technical success of PTUB was 89.2%, with a mean irradiation dose of 76.9 mGy·cm2 ± 12.2. A total of 67.6% (25/37) of the cases were correctly diagnosed with malignancy, whereas 8 cases were confirmed to be true negatives. There were 4 false negatives and no false positives. PTUB had a sensitivity, specificity, PPV, NPV, and OA of 86.2% (25/29), 100% (8/8), 100% (25/25), 66.7% (8/12), and 89.2% (33/37), respectively. Eleven patients (29.7%) experienced Grade 1 adverse events (transient aggravated hematuria). CONCLUSIONS: PTUB appears to be a safe and effective alternative to ureteroscopic biopsy for ureteral obstruction.

Magnetic Compression Anastomosis of Benign Short-Segment Ureteral Obstruction.

PURPOSE: To investigate the feasibility, safety, and effectiveness of magnetic compression anastomosis of benign short-segment ureteral obstruction. MATERIALS AND METHODS: Patients referred for failure of ureteral double-J stent placement because of impassable benign ureteral obstruction were included. Eleven patients (11 ureters) with a mean age of 57.5 years (range, 19-85 years; 8 women) underwent ureteral magnetic compression anastomosis. All patients had indwelling nephrostomy catheters. In all patients, anterograde and retrograde ureteral stent placements were unsuccessful using either interventional or cystoscopic access. Ureteral magnetic compression anastomosis was performed as a 2-step procedure. In the first step, magnets were placed. In the second step, the stricture was traversed via magnetic compression anastomosis. Successful establishment of anastomosis and ureteral double-J stent placement were considered technical success. The mean time for complete magnetic adherence and fluoroscopy time for each procedure were recorded. RESULTS: Five patients (45%) had an ileal conduit. The technical success rate was 91% (n = 10/11). The mean time for magnetic adherence was 5.7 days (SD ± 1.3). The mean single-rotation fluoroscopy times during the first and second steps of the procedure were 9.45 minutes (SD ± 2.09) and 15.70 minutes (SD ± 2.62), respectively. Magnets were removed with the support of either balloon catheters (n = 9) or biopsy forceps (n = 2). No procedure-related adverse events occurred. CONCLUSIONS: Magnetic compression anastomosis of benign ureteral obstruction is feasible and safe and can be performed in an interventional radiology (IR) suite without the need for endoscopy.

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

OBJECTIVE: 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 AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Risk factors for adverse outcomes after pediatric pyeloplasty: A retrospective cohort study.

PURPOSE: To identify the risk factors for adverse outcomes after pediatric pyeloplasty. METHODS: We conducted a retrospective review of all children under the age of 14 years who underwent primary pyeloplasty for unilateral ureteropelvic junction (UPJ) obstruction at a single teaching hospital in Tunisia between January 1, 2013, and December 31, 2022. RESULTS: A total of 103 patients were included. Median age of patients at surgery was 27 months (interquartile range [IQR], 13-44). On ultrasound, median renal pelvic anteroposterior diameter was 3.2 cm (IQR, 2.3-4), and the median renal cortex thickness (RCT) was 2.5 mm (IQR, 2-3.5). Median differential renal function (DRF) on preoperative radionuclide renal scan was 40% (IQR, 30-46). Postoperative adverse outcomes occurred in 28 patients (27.2%). These included 19 cases of urinary tract infections (UTIs), 11 cases of UPJ restenosis, four cases of UPJ leakage, two cases of urinoma, and two cases of diversion-related complications. Multivariate logistic regression analysis revealed two factors significantly and independently related to postoperative negative outcomes: RCT <3 mm and DRF > 50%. CONCLUSION: Our study demonstrated that preoperative RCT on ultrasound of less than 3 mm and preoperative DRF on radionuclide renal scan of more than 50% were independent risk factors for adverse outcomes following pediatric pyeloplasty. These factors could be of interest in identifying, early on, patients who will develop postoperative negative outcomes, giving them more attention and support, and explaining the prognosis to the patient and family.

Analysis of the Efficacy of Elastography in Comparison with Dynamic Renal Nuclear Scintigraphy in the Evaluation of Unilateral Pelvi-Ureteric Junction Obstruction.

INTRODUCTION: In hydronephrosis due to pelviureteric junction obstruction (PUJO), an obstruction to urine flow may lead to increased pelvic pressure, which may cause interstitial fibrosis and renal impairment. Recently, there have been reports on renal pelvic assessment using ultrasound elastography (USE). This study was conducted to see if USE can evaluate PUJO and if it can be correlated to the findings of the dynamic renal nuclear scan. MATERIAL AND METHODS: In this observational study, only patients with unilateral PUJO underwent acoustic radiation force impulse (ARFI) elastography. A rectangular region of interest (ROI) measuring 5 × 10 mm was positioned on the cortex region of the upper, mid, and lower poles of the affected kidney. Three valid measurements were obtained, from which a mean value was calculated. A dynamic renal nuclear scan using Technetium-99m ethylene dicysteine (EC or TC99 m EC) was obtained and split renal function (SRF) was used for comparison. RESULTS: In the group of 20 patients, the mean age was 3.37 years. The mean SRF of the affected kidney was 26.65 %, and the corresponding USE value was 0.45 kpa. The Spearman's rho correlation coefficient for SRF and USE was 1 and 0.672, respectively (p = 0.001). Elastography was not feasible if SRF was less than 20 %. CONCLUSION: USE may be able to comment on the renal functional status of hydronephrosis. If USE is reported as non-feasible, it may suggest that renal function is grossly compromised. It may serve as an alternative diagnostic modality for renal functional evaluation. LEVEL OF EVIDENCE: Level II, Prospective Cohort Study.

[Evaluation of the Effects of Long-Term Indwelling Ureteral Stents on Preserving Renal Parenchyma and Function in Patients with Ureteral Stenosis].

Although ureteral stenting is a common conservative treatment for ureteral stricture, it is unclear whether a long-term indwelling ureteral stent protects the kidney against parenchymal atrophy and functional deterioration. In this study, we evaluated the changes in renal parenchymal thickness (RPT) and estimated the glomerular filtration rates (eGFR) in patients with indwelling ureteral stents for one year or more. As a control, we also evaluated changes in RPT associated with indwelling percutaneous nephrostomy (PNS) for one year or more. Polymer ureteral stents were used and replaced every three months. RPT was measured using computed tomography (CT). Totally, 69 renal units in 55 patients with baseline and follow up CT scans available were enrolled. The median follow-up period was 29 months. The etiologies of ureteral obstruction were malignant and benign disease in 27 and 28, respectively. RPT was reduced obviously in most cases. At 1 year, the median reduction rate of RPT was 17.3% in unilateral cases, which was significantly higher than that in the healthy contralateral kidney. There was a strong correlation between eGFR and total RPT including the contralateral kidney. The reduction rate of RPT in kidneys with ureteral stents including bilateral cases was also significantly higher than that in 39 renal units of 35 patients with PNS. The results of this study suggest that the long-term efficacy of indwelling ureteral stents in preserving renal function is limited. Regular imaging may be essential to evaluate the residual renal function.

Localized amyloidosis of the ureter: a case report.

BACKGROUND: Amyloidosis is a collection of disorders characterized by the extracellular deposition of amyloid, a specialized fibrous protein, in diverse tissues, leading to functional impairments. CASE PRESENTATION: A 70-year old Asian-Japanese female was referred to our department for further examination of her left hydronephrosis come from lower ureteral obstruction. Contrast enhanced CT and retrograde pyelo-nephrography revealed left ureteral tumor. Though ureteroscropic biopsy did not show malignant pathological findings, ureteroscopic image suspected malignant disease, thus nephroureterectomy was performed. Pathological findings revealed localized ureteral amyloidosis. Whole body examination including gastro endoscopy and cardio ultrasonography could not reveal amyloidosis except ureter. She was free from recurrence 9 months postoperatively. CONCLUSION: We herein report a rare case of localized ureteral amyloidosis.

Combination of robot-assisted laparoscopy and ureteroscopy for the management of complex ureteral strictures.

BACKGROUND: To summarize the efficacy of combined robot-assisted laparoscopy and ureteroscopy in treating complex ureteral strictures. METHODS: Eleven patients underwent combined robot-assisted laparoscopy and ureteroscopy for ureteral strictures between January 2020 and August 2022. Preoperative B-ultrasound, glomerular filtration rate measurement, and intravenous pyelography showed different degrees of hydronephrosis in the affected kidney and moderate to severe stenosis in the corresponding part of the ureter. During the operation, stricture segment resection and end-to-end anastomosis were performed using the da Vinci robot to find the stricture point under the guidance of a ureteroscopic light source in the lateral or supine lithotomy position. RESULTS: All the patients underwent robot-assisted laparoscopy and ureteroscopy combined with end-to-end ureterostenosis. There were no conversions to open surgery or intraoperative complications. Significant ureteral stricture segments were found in all patients intraoperatively; however, stricture length was not significantly different from the imaging findings. Patients were followed up for 3-27 months. Two months postoperatively, the double-J stent was removed, a ureteroscopy was performed, the ureteral mucosa at the end-to-end anastomosis grew well, and the lumen was patent in all patients. Furthermore, imaging examination showed that hydronephrosis was significantly improved in all patients, with grade I hydronephrosis in three cases and grade 0 hydronephrosis in eight cases. No recurrence of ureteral stricture was observed in patients followed up for > 1 year. CONCLUSION: Robot-assisted laparoscopy combined with ureteroscopy is an effective method for treating complex ureteral strictures and can achieve accurate localization of the structured segment.

Endoscopic balloon dilation of primary obstructive megaureter: is fluoroscopic guidance necessary?

OBJECTIVE: To compare the long-term effectiveness, complications, and outcomes of primary obstructive megaureter (POM) treated by endoscopic balloon dilation under fluoroscopic guidance versus not using radioscopy during the procedure. PATIENTS AND METHODS: A comparative study between POM cases treated at our institution by endoscopic balloon dilation (EBD) under fluoroscopic guidance (FG) (n = 43) vs no fluoroscopic guidance (NFG) (n = 48) between the years 2004 and 2018 was conducted. The procedure in FG consisted of performing a retrograde pyelography before dilation. Then, a guidewire is introduced to the renal pelvis, and the dilation of the vesicoureteral junction is performed using high-pressure balloon catheters under fluoroscopic vision. Finally, a double-J stent is placed between the renal pelvis and bladder. The procedure in NFG was performed exclusively under cystoscopic vision without radiological exposure. Complications, outcomes, and success rates were analyzed using Spearman's correlation test. Mean follow-up was 12.5 ± 2.2 years in FG and 6.4 ± 1.3 years in NFG. RESULTS: MAG-3 showed significant differences in renal drainage before and after endoscopic treatment in both groups (p < 0.001 T-test). Statistical analysis did not reveal differences between groups in initial technical failure (r: - 0.035, p = 0.74), early postoperative complications (r: - 0.029, p = 0.79), secondary VUR (r: 0.033, p = 0.76), re-stenosis (r: 0.022, p = 0.84), long-term ureteral reimplantation (r: 0.065, p = 0.55), and final outcome (r: - 0.054, p = 0.61). The endoscopic approach of POM had a long-term success rate of 86.5% in FG VS 89.6% in NFG. CONCLUSIONS: Endoscopic balloon dilation of POM can be done with no radiation exposure with similar results, effectiveness, and outcomes.

Decreased percent change in renal pelvis diameter on diuretic functional magnetic resonance urography following administration of furosemide may help characterize unilateral uretero-pelvic junction obstruction.

BACKGROUND: A well-established definition of obstruction in the setting of congenital hydronephrosis is lacking. Multiple imaging modalities and radiographic characteristics or parameters have been described to help confirm the diagnosis of ureteropelvic junction obstruction (UPJO). We sought to evaluate the change in anterior-posterior renal pelvic diameter (APRPD) following furosemide administration in patients with unilateral hydronephrosis and confirmed UPJO on functional magnetic resonance urography (fMRU) who underwent pyeloplasty. MATERIALS AND METHODS: There were 49 patients who met inclusion criteria (11 females, 38 males; average age 2.2 years, SD 3.4 years) from February 2006 to September 2020, diagnosed with unilateral hydronephrosis (SFU Grade 3-4) who underwent fMRU prior to pyeloplasty for confirmed UPJO. 29 of the included patients also underwent a post-pyeloplasty fMRU. A weight-adjusted dose of 1 mg/kg of furosemide (max 20 mg/kg) was administered intravenously. Two board-certified pediatric radiologists measured the APRPD of the obstructed and non-dilated kidneys prior to pyeloplasty and APRPD of the hydronephrotic kidneys on the post-pyeloplasty follow up fMRUs. Measurements were performed on images prior to and approximately 30 min following furosemide injection. RESULTS: The average APRPD before furosemide injection in the obstructed kidney prior to pyeloplasty was 26.3 mm (SD 9.0 mm) compared to the non-dilated (not obstructed) kidney measurement of 5.1 mm (SD 3.6 mm) (p < 0.001). Following administration of furosemide, the average APRPD was 31.4 mm (SD 8.8 mm) in the obstructed kidney, and 7.8 mm (SD 4.1 mm) in the non-dilated kidney (p < 0.001). After pyeloplasty, the pre-furosemide APRPD measurement was 17.8 mm (SD 11 mm), which was significantly less compared to the pre-pyeloplasty APRPD (p < 0.001). The post-pyeloplasty, post-furosemide APRPD measurement was 25.8 mm (SD 12 mm), also significantly less compared to the pre-pyeloplasty measurement (p = 0.02). The changes in APRPD in the obstructed kidney prior to pyeloplasty was 5.1 mm (SD 3.5 mm) and after pyeloplasty was 8 mm (SD 4.6 mm) (p = 0.002). Change in APRPD in the non-dilated kidney was 2.7 mm (SD 2.3 mm). Percent APRPD change in the obstructed kidney was 22.9% (SD 18.5%), which was significantly less than 33.3% (SD 22.1%) in the post-pyeloplasty kidney (p = 0.028) and 82.8% (SD 87.9%) in the non-dilated kidney (p < 0.001). CONCLUSIONS: A relatively smaller change in APRPD on fMRU following administration of furosemide in the setting of UPJO may serve as another predictive characteristic of obstructed kidneys.

Supranormal differential renal function on MAG3 scan in children with ureteropelvic junction obstruction - Prevalence and pyeloplasty during follow-up.

BACKGROUND: Children with suspected ureteropelvic junction obstruction (UPJO) may present with a paradoxical ipsilateral supranormal differential renal function (snDRF) on 99mTechnetium mercaptoacetyltriglycine scintigraphy (MAG3 scan). OBJECTIVE: The aim was to investigate the prevalence of snDRF, the risk of pyeloplasty among children with UPJO and snDRF, and to explore the experience of snDRF among international pediatric urologists. METHODS: A retrospective cohort study of children with suspected unilateral UPJO who underwent MAG3 scan at four hospitals in Sweden between 2005 and 2020. SnDRF was defined as DRF ≥55%. Normal DRF was defined as DRF 45-54%. Primary outcome was risk of pyeloplasty. Indications for pyeloplasty were loss of >10%-points of differential renal function (DRF), ipsilateral DRF <40%, or symptomatic UPJO. Logistic and cox regressions were performed in univariate and multivariable analyses, adjusting for age, gender, year, laterality, antenatal hydronephrosis, anterior-posterior diameter (APD), and kidney size. An international questionnaire regarding the management of snDRF was developed and distributed to pediatric urologists. RESULTS: The prevalence of snDRF was 19%. SnDRF was more common in boys, children with antenatal hydronephrosis, children undergoing their first MAG3 scan at a younger age, and in the left kidney. After further exclusion of 70 children with DRF <45%, a total of 264 were included for longitudinal follow-up of median 6.6 (IQR 2.5-11.5) years. SnDRF was not associated with increased risk of pyeloplasty (adjusted OR 0.98 (95% CI 0.41-2.33), p = 0.96, and adjusted HR 1.00 (95% CI 0.53-1.91), p = 0.99) or time to pyeloplasty (1.1 years vs. 1.6 years, p = 0.40). Among the 79 surveyed pediatric urologists, a majority would not change clinical UPJO-management based on the presence or absence of ipsilateral snDRF. DISCUSSION: There are only a few studies considering the need of pyeloplasty based on the presence of snDRF and this is the first survey among pediatric urologists on its management. With more included patients than previous studies, this study showed a snDRF prevalence of 19%, congruent with the findings of others. The underlying cause of snDRF is debated, but it cannot solely be explained as an artifact of hydronephrotic kidneys. Further studies on the clinical implications of snDRF are warranted, since DRF influences the decision to operate. CONCLUSION: A fifth of all children with suspected UPJO presented with ipsilateral snDRF on initial MAG3 scan, and snDRF was not associated with a greater risk of pyeloplasty. Supported by a large group of international pediatric urology colleagues, this study concludes that the same clinical follow-up and management apply, regardless of presence of snDRF.

Interventional Treatment Methods for Ureteral Complications After Kidney Transplant: A Single-Center Experience.

OBJECYIVES: Ureteral complications are one of the most common complications after kidney transplant. Although these complications have been treated surgically in the past, almost all can be successfully treated with interventional methods today. In this study, we assessed the interventional treatment of ureteral complications after kidney transplants performed in our center and the long-term results of these treatments. MATERIALS AND METHODS: We performed a retrospective analysis of 2223 kidney transplant recipients seen between January 1, 2000, and May 1, 2020. Among these, 70 kidney transplant recipients who experienced ureteral leakage or ureteral obstruction in the early or late posttransplant period were included in the study. Complications within the first 2 months posttransplant were classified as early complications, whereas those occurring after 2 months were considered late complications. We treated all patients with interventional methods. RESULTS: In review of patients, 44 patients were diagnosed with ureteral obstruction (22 patients were early obstruction, 22 were late obstruction) and 26 patients with ureteral anastomosis leakage. All patients with early and late ureteral obstruction were successfully treated with percutaneous methods. In the group of patients with ureteral leakage, all patients except 2 patients were treated with interventional methods. For 2 patients with ureteral leakage, surgical treatment was necessary because of persistent leakage despite percutaneous treatment methods. CONCLUSIONS: Ureteral complications after kidney transplant can be successfully treated with interventional methods in experienced centers without the need for surgery.