Ureteropelvic Junction Obstruction Research Articles

Our experience with management of congenital urological pathologies in adulthood: What pediatric urologists should know and adult urologists adopt in pediatric practice experience.

To summarize our experience in the management of congenital anomalies in the kidney and urinary tract (CAKUT) in adults. We conducted a retrospective chart review of all adult patients who underwent primary surgical intervention for CAKUT between 1998 and 2021. The study included 102 patients with a median age of 25 (interquartile range, 23-36.5). Of these, 85 (83.3%) patients reported normal prenatal ultrasound, and the remaining 17 (16.7%) patients were diagnosed with antenatal hydronephrosis. These patients were followed-up conservatively postnatally and were discharged from follow-up because of the absence of indications for surgical intervention or because they decided to leave medical care. All studied adult patients presented with the following pathologies: 67 ureteropelvic junction obstructions, 14 ectopic ureters, 9 ureteroceles, and 6 primary obstructive megaureters, and the remaining 6 patients were diagnosed with vesicoureteral reflux. Forty-three percent of the patients had poorly functioning moieties associated with ectopic ureters or ureteroceles. Notably, 67% of patients underwent pyeloplasty, 9% underwent endoscopic puncture of ureterocele, 3% underwent ureteral reimplantation, 6% underwent endoscopic correction of reflux, 7% underwent partial nephrectomy of non-functioning moiety, and the remaining 9% underwent robotic-assisted laparoscopic ureteroureterostomy. The median follow-up period after surgery was 33 months (interquartile range, 12-54). Post-operative complications occurred in 5 patients (Clavien-Dindo 1-2). Patients with CAKUT present clinical symptoms later in life. Parents of patients diagnosed during fetal screening and treated conservatively should be aware of this possibility, and children should be appropriately counseled when they enter adolescence. Similar surgical skills and operative techniques used in the pediatric population may be applied to adults.

Voiding Cystourethrogram Before Pyeloplasty: To Do or Not To Do?

To assess the incidence of concomitant vesicoureteral reflux (VUR) in unilateral cases of ureteropelvic junction obstruction(UPJO) and to identify factors that predict VUR. Files of 381 pediatric patients who underwent unilateral pyeloplasty between 2000 and 2017 were retrospectively reviewed.A total of 270 patients with available data and ≥5 years of follow-up were eligible for this study.Demographic parameters,preoperative hydronephrosis grade,renal pelvis anteroposterior diameter(APD),renal parenchymal thickness(PT),split renal functions on MAG-3 scan and VUR status were noted.The patients were divided into two groups:Those with concomitant VUR(Group I, n:24, 8.9%) and those without VUR(Group II,n:246, 91.1%). Among 270 patients(205 boys,75.9%) with a median age of 4 months(2-98),197 (72.9%)had antenatal hydronephrosis.Median follow-up was 11 years(5-22).Among 24 patients with concurrent VUR,6(25%) had Grade II VUR,whereas Grade III-V VUR was detected in 18(75%).Of these,12(50%) had ipsilateral VUR,3(12.5%) had contralateral,and 9(37.5%) had bilateral VUR.In a median 137-month follow-up,spontaneous VUR resolution was observed in 6(25%) patients,whereas 15 (62.5%) patients underwent endoscopic subureteral injection and 3(12.5%) patients ureteroneocystostomy,respectively.Preoperative APD[35.5, IQR(27.6-36.0) vs. 26.5 IQR(25.0-35.0), p=0.004] were significantly higher in Group I,whereas Group I had significantly lower PT[3.7, IQR(3.4-6.4) vs. 5.8 IQR(4.4-6.1), p=0.026].Predictive factors for concomitant VUR were presentation with febrile UTI(OR:2.769,p=0.048), PT<3.95 mm(OR:1.367,p=0.043),and APD>28.8 mm (OR:1.035,p=0.001). Our results indicated that concomitant VUR and UPJO might be detected in 1 out of every 11 patients undergoing pyeloplasty,while some type of surgical intervention for VUR was required in 75% of these patients.Thus,VCUG prior to pyeloplasty may be limited in those presenting with febrile UTI,having higher APD and lower PT on preoperative urinary ultrasonography.

Ureteropelvic junction obstruction with polyps in children: clinical manifestations and supranormal preoperative differential renal function.

To describe and analyze the clinical manifestation and pre-DRF of UPJO children with polyps and explore the possible influencing factors of supranormal pre-DRF. All patients undergoing primary Anderson-Hynes pyeloplasty for UPJO due to polyp were retrospectively reviewed. Patients' characteristics, parameters of ultrasound and dynamic renograms (DR) were recorded in elaborate. Pre-DRF in groups of different age, weight, gender, pain, grade of hydronephrosis, anterio-posterior pelvic diameter (APD), length of kidney and postoperative ultrasonic parameters were compared. A total of 18 UPJO children with polyps were included. Five (27.78%) patients had SFU III grade of hydronephrosis. Seven (38.89%) patients were supranormal pre-DRF. All patients had pre-DRF > 40%. Drainage curve was delayed excretion in 12 (66.67%) patients and T1/2 < 20min was in 4 (22.22%) patients. Among the 16 patients who underwent preoperative IVP examination, 15 (93.75%) patients had concentration of intrarenal pelvis contrast agent within 10min. No significant difference in post-APD reduction rate and post-minPT increased was found between supranormal pre-DRF and non-supranormal pre-DRF groups. The supranormal pre-DRF was more likely to occur in young and low-weight children. The preoperative renal function of UPJO patients with polyps was well preserved, and 38.89% of them had supranormal pre-DRF. Patients with supranormal pre-DRF can be managed with the same strategies as those with normal renal function.

Epidemiology of Infantile Ureteropelvic Junction Obstruction in the US

To describe sex- and diagnosis-specific comorbidities, outcomes, and secular trends associated with ureteropelvic junction obstruction (UPJO) in a large, real-world population diagnosed with hydronephrosis in infancy. We identified all infants ≤1year old with ≥1 claim in the Optum Clinformatics 2007-2020 nationwide population database and used univariable and multivariable Cox regression analyses to estimate associations of demographic and clinical characteristics of infants with a UPJO diagnosis with surgical status. Of 22,349 infants with hydronephrosis (1.1% of infants; males-1.4%, females-0.7%), 1722 (7.7%; 7.9%-males, 7.2%-females) had UPJO. Follow-up was ≥1year in 1198 (70%) and ≥3years in 555 (32%) cases, and UPJO repair was performed in 542 children (31.5%; 32.3%-males, 29.5%-females); 77.7% within 1year and 97.3% within 3years. UPJO repair was associated with prior urinary tract infection (UTI) (hazard ratio (HR) 1.41, 95% confidence interval (CI) 1.12-1.76) and South (HR 1.42, 95% CI 1.14-1.78) or Midwest (HR 1.60, 95% CI 1.26-2.04) geographic region but did not change over time. This population-based study provides a real-world view of postnatally diagnosed hydronephrosis, focusing on UPJO, for which 522 cases (∼1/3) had ≥3years continuous coverage. UPJO-associated comorbidities were more common in females, and the frequencies of UPJO-associated surgery and comorbidities were higher than in other studies. Other than UTI, no other associated kidney or urinary tract diagnoses were associated with UPJO repair. We identified unique sex- and diagnosis-specific differences in associated comorbidities and interventions in children diagnosed with UPJO in the first year of life.

Ureteropelvic Junction Obstruction (UPJO)

Ureteropelvic junction obstruction (UPJO) is an abnormality in the canal that connects the renal pelvis to the ureter, leading to impairment of urinary flow. The use of maternal ultrasound has increased the number of UPJO during the antenatal period. Histopathological features in UPJO are important for establishing the diagnosis and understanding the pathogenesis of the condition. The current study aims to explain the irregularity of the muscularis propria and a decreased Cajal cells in the affected segment of the UPJO.

The Minimal Utility of Analyzing Ureteropelvic Junction Tissue at the Time of Pyeloplasty

Introduction: Ureteropelvic junction obstruction is a common cause of upper tract obstruction that often necessitates surgical intervention because of its severe implications. A high proportion of these surgeries include pathologic analysis of this tissue with unclear clinical value. We examined our institution's practices concerning sending the ureteropelvic junction (UPJ) specimens for pathology analysis, its clinical value, and the associated costs for both pediatric and adult cases. Methods: We performed retrospective chart review using Current Procedural Terminology codes for pyeloplasty over 8 years. Clinical variables were extracted from operative reports, path reports, and postoperative clinic notes. Pathology results were classified dichotomously as “benign” or “malignant” and subsequently assigned to 1 of 4 categories—inflammation, fibrosis, muscular hyperplasia, or no atypical findings. Results: Two hundred sixty-nine pyeloplasty surgeries were included, 68% of which were in children. Pathologic analysis was requested in most of the cases (91%), and this was slightly more common in adults (94%) than in pediatric patients (90%). All available pathology reports found benign findings in the UPJ specimen, mostly commonly categorized as “normal.” No cases of malignancy were noted. At the list price for pathologic analysis, $103,027 was spent over 8 years without the discovery of clinically significant pathology findings. Conclusions: There was a lack of clinically meaningful results from pathologic analysis of UPJ specimens excised during pyeloplasty. A UPJ specimen should not be routinely sent for pathologic analysis rather selectively if there is clinical concern for nonbenign etiology of UPJ obstruction.

Does preoperative screening VCUG affect the outcomes and complications of pyeloplasty in patients with ureteropelvic junction obstruction?

The role of voiding cystourethrogram (VCUG) in evaluating vesicoureteral reflux (VUR) in patients with known ureteropelvic junction obstruction (UPJO) remains unclear. While VCUG is frequently performed, the incidence of concomitant VUR and UPJO is low, and VUR is often low-grade with high rates of spontaneous regression. To analyze the clinical relevance of VCUG in patients with UPJO by determining its incidence and studying the difference in clinical outcomes between patients with known, unknown, and negative VUR. Retrospective review of patients with UPJO who underwent pyeloplasty from 2012 to 2020 with <18 years-old, unilateral UPJO, postoperative follow-up of ≥2 months and had at least 1 renal ultrasound (US) after pyeloplasty. Results were compared among 3 groups: patients who underwent VCUG before pyeloplasty and were found to have VUR (group 1), patients who underwent VCUG before pyeloplasty without VUR (group 2), and patients who did not have a VCUG before pyeloplasty (group 3). A total of 275 patients met the inclusion criteria, of which 21 patients were classified in group 1, 166 patients in group 2, and 88 patients in group 3 (Table). The age at preoperative VCUG was 14.7±32.9 months in group 1 and 15.17±35.8 months in group 2 (p=0.960). Overall, the incidence of concomitant UPJO and VUR was 11.2%. In group 1 the initial VUR grade was 5 in 2 patients, 4 in 3, 3 in 5, 2 in 7, and 1 in 4 patients. Of these, only 1 patient required ureteral reimplantation after pyeloplasty. Post-pyeloplasty, no significant differences were observed in complications (p=0.7436), length of follow up (p=0.3212), SFU grade 4 hydronephrosis (p=0.2247), postoperative UTIs (p=0.1047) and pyeloplasty success rate (p=0.4206) among the 3 groups. Despite the use of antibiotic prophylaxis being significantly different amongst the three groups (p<0.001), it was not associated with a lower incidence of postoperative UTIs (group 1 p=0.068, group 2 p=0.486, group 3 p=1). In patients with reflux, an increase in age was associated with a decrease in the rates of complications (p=0.019). We found no significant difference in the outcomes in patients who had a preoperative VCUG as compared to those who did not. The preoperative diagnosis of VUR by VCUG changed the management in less than 1% of the study population and thus its role in patients with UPJO should be reevaluated.

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

To identify the risk factors for adverse outcomes after pediatric pyeloplasty. 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. 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%. 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.

The efficacy of robotic-assisted laparoscopic pyeloplasty for pediatric ureteropelvic junction obstruction: a systematic review and meta-analysis.

To evaluate the safety and effectiveness of robotic-assisted laparoscopic pyeloplasty (RALP) for treating pediatric ureteropelvic junction obstruction through an extensive comparison of RALP, open pyeloplasty (OP) and laparoscopic pyeloplasty (LP). We conducted a comprehensive search of the following databases: PubMed, Excerpta Medica Database, Cochrane Library, Web of Science database, China National Knowledge Infrastructure, WanFang Data, and China Biology Medical Disc. Baseline data were compared, the sources of heterogeneity were assessed, and publication biases were detected. This study was registered with PROSPERO (CRD42023415667). 26 studies with 6074 cases performing pyeloplasty were included, and the overall data are comparable. Our analysis showed no significant difference in success rate and postoperative complications between RALP and OP, and RALP is associated with a shorter length of stay (LOS) (MD - 1.00 95%CI - 1.45 to - 0.55, p < 0.0001). In addition, compared to LP, RALP was associated with a shorter anastomosis time (MD - 18.35 95%CI - 29.88 to - 6.82, p = 0.002) and fewer postoperative analgesics (MD - 0.09 95% CI - 0.18 to - 0.01, p = 0.03); however, RALP has a longer operative time (OT) (MD 52.39, 95% CI 39.75-65.03, p < 0.00001) and higher cost. The heterogeneity of OT may be influenced by factors, such as age and region, while the heterogeneity of LOS primarily stems from regional differences. No significant publication bias was detected. Our meta-analysis shows that RALP can be an alternative to OP and LP with a high success rate, minimal postoperative complications, and shorter LOS. In addition, RALP contributes to reduce anastomosis time and postoperative analgesic drugs. However, further well-designed, large-scale, randomized controlled trials with additional parameters are needed to conduct a more comprehensive analysis of heterogeneity.

Robot-assisted pyeloplasty for ureteropelvic junction obstruction: initial experience with the novel avatera system.

This pilot study was designed to interpret the technically specific features of the avatera robotic system and present our initial experience with this novel platform in robot-assisted pyeloplasty (RAP). A single-center prospective study was conducted including all patients who underwent RAP with the avatera robotic system from June 2022 to October 2022 in our Department. Transperitoneal robot-assisted dismembered pyeloplasty was performed in all cases. The trocar placement and the surgical technique were similar in all patients. The successful completion of the procedures, operation time (including draping, docking and console time), decrease in hemoglobin postoperatively, and presence of any complications were the study's primary endpoints. In total, nine patients underwent RAP using the avatera system. All procedures were successfully completed. The draping of the robotic unit was completed in a median time of 10min (range 7-15), while the median docking time was 17min (range 10-24). The median console time was 88min (range 78-116) and no complications were noticed. The median hemoglobin drop was calculated to 0.7g/dL (range 0.4-1). During the mean follow-up of 9.33 ± 2.78months, no late postoperative complications were noticed. The early outcomes of the use of the novel avatera system in RAP are presented. All operations were successfully completed with safety and efficacy, without complications or significant blood loss.

Combination of robot‐assisted laparoscopic pyeloplasty for lower moiety ureteropelvic junction obstruction in a partial duplex system and percutaneous endoscopic surgery for renal calculi reusing the port for robotic pyeloplasty

IntroductionUreteropelvic junction obstruction is often associated with renal calculus formation. However, there is no report of using robot‐assisted laparoscopic pyeloplasty combined with percutaneous endoscopic surgery for ureteropelvic junction obstruction and renal calculi in a partial duplex system.Case presentationA 19‐year‐old female patient with lower moiety ureteropelvic junction obstruction and renal calculi in a partial duplex system was referred to our hospital because of left lumbar pain, left acute pyelonephritis, and an increase in left renal calculi during follow‐up at the referral hospital. To prevent the complication of percutaneous nephrolithotripsy following pyeloplasty, robot‐assisted laparoscopic pyeloplasty combined with percutaneous endoscopic surgery was performed. Two years after surgery, the patient reported no left lumbar pain.ConclusionThe combination of robot‐assisted laparoscopic pyeloplasty and percutaneous endoscopic surgery can be proposed as a safe and less‐invasive treatment option for ureteropelvic junction obstruction and renal calculi in a partial duplex system.

Determination of tissue tracer transit of Technetium-99m-mercaptoacetyltriglycine diuretic renography in infants with suspected ureteropelvic junction obstruction - A multicenter prospective observational study

There is an ongoing controversy regarding management of ureteropelvic junction obstruction in infants, with a shift towards a non-operative approach. However, precise predictors of outcome are lacking. Recent studies postulated a high prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit with regard to the development of an impaired differential renal function and its potential improvement following pyeloplasty. To evaluate the prognostic value of Technetium-99m-mercaptoacetyltriglycine tissue tracer transit for the occurrence of changes in differential renal function in infants with suspected unilateral ureteropelvic junction obstruction in a prospective observational multicenter study. Infants below 3 months of age with a unilateral isolated hydronephrosis≥grade 3 received ultrasound and Technetium-99m-mercaptoacetyltriglycine diuretic renography at two different time points (timepoint 1 and timepoint 2). Data were analyzed at local centers and at the study center and were collected in an internet-based database system. Tissue tracer transit was determined for each diuretic renography, inter-observer variation for tissue tracer transit and standard parameters for judgement of differential renal function development were assessed. Thirty-seven patients were analyzed. Median age was 11 weeks (7-15) at timepoint 1 and 26 weeks (19-33) at timepoint 2. A delayed tissue tracer transit at timepoint 1 was not associated with deterioration of differential renal function at timepoint 2 in both, locally (10/37 cases) and centrally (4/37) analyzed cases. However, sensitivity and specificity were poor. The intraclass correlation coefficient comparing local and central findings of tissue tracer transit and renal drainage demonstrated poor or fair agreement. Analysis of standard parameters for differential renal function development revealed a prognostic value only for the dichotomized anteroposterior renal pelvic diameter (APD, p=0.03, 95%-CI 1.2-22.2). Regarding the primary endpoint of our study, we could not confirm the hypothesis that delayed tissue tracer transit reliably predicts a subsequent decline in differential renal function in the cohort of patients studied. Whether the low age of the patients, technical problems in the correct assessment of tissue tracer transit by the investigator in early infancy, the study design, or the parameter itself played a role is debated. In the presented setting tissue tracer transit was not useful as a predictive parameter for deterioration of differential renal function in infants with suspected unilateral ureteropelvic junction obstruction. Sensitivity and specificity of tissue tracer transit were not sufficient for risk stratification. Improved utility of tissue tracer transit as a marker might be achieved using a different study setting.

Pyeloplasty in Children with Ureteropelvic Junction Obstruction and Associated Kidney Anomalies: Can a Robotic Approach Make Surgery Easier?

Robot-assisted pyeloplasty is widely used in pediatric surgery because of its well-known advantages over open or laparoscopic surgery. The aim is to explore our experience and evaluate the achievements we have made. We evaluated patients undergoing robotic pyeloplasty from January 2016 to November 2021, including those who presented with a ureteropelvic junction obstruction associated with other anomalies of the kidney. The parameters examined were: age, weight, associated renal malformations, conversion rate, operative time, and intra- and postoperative complications. Of 39 patients, 7 (20%) were included, of whom 5 (71%) were male and 2 (29%) were female. The mean age at surgery was 84 months (range 36-180 months), and the mean weight at surgery was 24.4 kg (range 11-40 kg). In five (71%) patients the ureteropelvic junction obstruction (UPJO) was left-sided and in two (29%) it was right-sided. In four (57%) cases, UPJO was associated with a horseshoe kidney, right-sided in one (25%) patient, and left-sided in the other three (75%). A 180° rotation of the kidney was present in one (14%) patient. Nephrolithiasis was present in two (29%) patients. The mean operative time was 160 min (range 140-240 min). The average bladder catheter dwell time was 1 day (range 2-3 days), while the average abdominal drainage dwell time was 2 days (range 2-4 days). The mean hospitalization time was 4 days (range 3-9 days). On average, after 45 days (range 30-65) the JJ ureteral stent was removed cystoscopically. No intraoperative complications were reported, while one case of persistent macrohematuria with anemia requiring blood transfusion occurred postoperatively. Ureteropelvic junction obstruction might be associated with other congenital urinary tract anomalies such as a duplicated collecting system, horseshoe kidney, or pelvic kidney. These kinds of malformations can complicate surgery and require more attention and accuracy from the surgeon. Our experience shows that, with regards to the robotic learning curve required for pyeloplasty, the treatment of the ureteropelvic junction in these situations does not present insurmountable difficulties nor is burdened by complications. The application of robot-assisted surgery in pediatric urology makes difficult pyeloplasties easier.

The Role of Renal Parenchyma to Hydronephrosis Area Ratio (PHAR) in Evaluation of Ureteropelvic Junction Obstruction in Children

Background The cortex/ pelvis ratio or parenchymal to pelvicalyceal area ratio can help initial evaluation and follow up of the children with uretropelvic junction obstruction as simple modality using the cut off which is 1.6 (pelvis/ cortex) ratio. There are many studies evaluating the various preoperative parameters which influence the post-operative outcomes after pyeloplasty. Practically there are many ultrasound parameters in the post-operative period which indicate the change in renal function. So, our rationale in this study is to evaluate the role of the parenchyma hydronephrosis area ratio (PHAR) in initial evaluation and follow up of UPJO patients in correlation to renal isotope studies. Objective To evaluate sonographic assessment of Renal Parenchyma to Hydronephrosis Area Ratio (PHAR) in the initial management and follow up of UPJO patients in correlation with the renal scan. Patients and Methods Site of the study: All patients were selected from the children who attended our outpatient department and have proven UPJO and meeting the criteria for the need of surgical intervention at Faculty of Medicine, Ain Shams University. Sample Size: 36 patients. Using PASS II Program for sample size calculation and according to (Rickard et al,2016), the expected AUC for PHAR prediction of future surgical intervention = 0.18, 30% rate of surgical intervention, setting power at 8% and error at 0.05, sample size of 36 patients will be needed. Results We enrolled 36 cases of children ≤ 16 years old (7.93 ± 0.83) with unilateral UPJO. Preoperative ultrasound parameters of the hydronephrotic kidneys [including degree of hydronephrosis, parenchymal thickness and PHAR] and renal isotope are measured &amp; compared with the same parameters after surgical repair of the UPJO (Anderson Hynes pyeloplasty) at 3rd months. After operation, 31 cases (86.1%) improved &amp; 5 cases not improved (13.9%). We find a significant change in all parameters at 3 months postoperatively (p &amp;lt; 0.01) as T ½ (25.22 ± 2.49 &amp; 17.57 ± 3.84) significantly decrease &amp; parenchymal thickness (9.42 ± 4.92 &amp; 15.12 ± 4.86), GFR of the affected kidney (34.31 ± 3.31 &amp; 48.32 ± 6.99) split renal function (37.30 ± 3.80 &amp; 44.03 ±4.11) and PHAR (0.86 ± 0.30 &amp; 2.45 ± 0.93) significantly increase post operatively. PHAR post operatively shows positive correlation with parenchymal thickness &amp; renal isotope while negative correlation with T ½. Conclusion PHAR is a promising parameter that can be estimated on presentation US to help predict the future need for surgery and follow up in children with ureteropelvic junction obstruction. Early identification of children who may require surgical intervention allows for closer surveillance of those patients as well as the opportunity for more selective ordering of invasive testing.

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

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. 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 1mg/kg of furosemide (max 20mg/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 30min following furosemide injection. The average APRPD before furosemide injection in the obstructed kidney prior to pyeloplasty was 26.3mm (SD 9.0mm) compared to the non-dilated (not obstructed) kidney measurement of 5.1mm (SD 3.6mm) (p<0.001). Following administration of furosemide, the average APRPD was 31.4mm (SD 8.8mm) in the obstructed kidney, and 7.8mm (SD 4.1mm) in the non-dilated kidney (p<0.001). After pyeloplasty, the pre-furosemide APRPD measurement was 17.8mm (SD 11mm), which was significantly less compared to the pre-pyeloplasty APRPD (p<0.001). The post-pyeloplasty, post-furosemide APRPD measurement was 25.8mm (SD 12mm), also significantly less compared to the pre-pyeloplasty measurement (p=0.02). The changes in APRPD in the obstructed kidney prior to pyeloplasty was 5.1mm (SD 3.5mm) and after pyeloplasty was 8mm (SD 4.6mm) (p=0.002). Change in APRPD in the non-dilated kidney was 2.7mm (SD 2.3mm). 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). 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.

Robot-assisted laparoscopic pyeloplasty is a valid option for ureteropelvic junction obstruction repair in adults with congenital renal abnormalities: a case series study

BackgroundCongenital renal anomalies are rare but may be associated with obstruction of the ureteropelvic junction. Given the rarity of simultaneous ureteropelvic junction obstruction [UPJO] and renal anomalies in the adult population, there is limited literature on approaching these patients. We report our experience with robotic assisted laparoscopic pyeloplasty for UPJO repair in this subset of patients.MethodsData on adult patients with simultaneous congenital renal abnormalities and UPJO who underwent robotic assisted laparoscopic pyeloplasty between 2008 and 2020 was reviewed. Pre-operative data, intraoperative parameters as well as post-operative data including symptom resolution and radiologic findings were recorded.ResultsTen patients, 4 female and 6 males, with a mean age of 47 years were identified as having simultaneous congenital renal abnormalities and UPJO. Anomalies identified were horseshoe kidney in four patients, duplex kidney with obstruction of one moiety in two patients, malrotated kidney in two patients, and pelvic kidney in two patients. Eight out of ten were symptomatic at presentation with flank pain being the most common symptom. Eight patients underwent robotic pyeloplasty via the dismembered technique, while two underwent robotic Y-V pyeloplasty. With a mean follow up time of 13 months, 8/9 (88%) symptomatic patients enjoyed symptom resolution. Post-op renogram was available for nine patients and showed resolution of obstruction in all patients (100%). One patient developed a urine leak which was managed successfully with drainage.ConclusionsRobotic assisted laparoscopic pyeloplasty is a safe, feasible and effective surgical approach in management of adult patients with concomitant UPJO and renal anomalies.

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

Children with suspected ureteropelvic junction obstruction (UPJO) may present with a paradoxical ipsilateral supranormal differential renal function (snDRF) on 99mTechnetium mercaptoacetyltriglycine scintigraphy (MAG3 scan). 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. 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. 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. 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. 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.

Percutaneous nephrostomy in infants: a 20-year single-center experience

To investigate the safety and efficacy of the imaging-guided percutaneous nephrostomy (PCN) procedure in infants. A total of 75 (50 boys; 66.7%) patients with a mean age of 121 days (range, 1-351 days) who underwent PCN over a period of 20 years were included in this retrospective study. For each patient, PCN indications, catheter size, the mean duration of catheterization, complications, and the procedure performed following nephrostomy were recorded. Technical success was determined based on the successful placement of the nephrostomy catheter within the pelvicalyceal system. Clinical success was defined as the complete resolution of hydronephrosis and improvement in renal function tests during follow-up. In patients with urinary leakage, technical and clinical success was determined based on the resolution of leakage. The technical success rate was 100%, and no procedure-related mortality was observed. In 11 patients (14.7%), bilateral PCN was performed. The most frequent indication of PCN was ureteropelvic junction obstruction (n = 41, 54.7%). Procedure-related major complications were encountered in two patients (methemoglobinemia and respiratory arrest caused by the local anesthetic agent in one patient and the development of urinoma caused by urinary leakage from the puncture site in the other). Mild urinary leakage was the only minor complication that occurred and only in one patient. Catheter-related complications were managed through replacement or revision surgery in 16 patients (21.3%). Imaging-guided PCN is a feasible and effective procedure with high technical success and low major complication rates, and it is useful for protecting kidney function in infants.

Robot‐assisted laparoscopic pyeloplasty in the management of lower pole ureteropelvic junction obstruction in a patient with an incomplete duplicated collecting system

IntroductionThe performance of robot‐assisted laparoscopic pyeloplasty has recently been increasing in frequency. However, patients with duplicated renal pelvises and ureters can present challenges.Case presentationA 71‐year‐old woman presented with flank pain and was diagnosed with ureteropelvic junction obstruction with an incomplete duplicated collecting system. Preoperative imaging did not reveal the details of the stenosis. Therefore, three reconstructive procedures were prepared: The Anderson–Hynes procedure, end‐to‐side pyeloureterostomy, and upper pole ureter to lower pole pyeloplasty with the Anderson–Hynes procedure for the lower pole. These procedures were determined by the length of the intact ureter and the presence of crossed vessels. During the surgery, the crossing vein was severed, allowing successful reconstruction with Anderson–Hynes anastomosis.ConclusionPreoperative evaluation and preparation of multiple surgical techniques are crucial in robot‐assisted laparoscopic pyeloplasty for incomplete duplicated collecting systems.

Mini-laparotomy in-situ pyeloplasty for repair of the ureteropelvic junction obstruction: Outcome of 150 cases.

To evaluate the functional and cosmetic outcomes of using the mini-laparotomy technique In Situ pyeloplasty to repair UPJ obstruction in young infants less than 6 months. Between January 2014 and March 2020, 150 young infants (less than 6 months) diagnosed with unilateral ureteropelvic junction obstruction (UPJO) and treated by mini-laparotomy In Situ pyeloplasty were included in this analysis. Once the UPJ has been identified, it was grasped by an Allis forceps for gentle traction. Two facing transverse incisions were made in the dilated pelvis facing the upper ureter. The transverse ureteric incision was then opened longitudinally. An anastomosis was done between the most dependent part of the lower lip of the pelvis and the apex of ureteric spatulation using 6/0 polyglactin (Vicryl®) sutures in the direction of "out-in-in-out." Follow-up was scheduled for 1 month and then every 3 months for a year with abdominal ultrasonography. DTPA was done for all patients 1 year after repair. The mean age was 3 ± 0.5 months, and the mean follow-up was 1.5 ± 0.3 years. Our technique was done in all included patients with a functional success of 96% (all patients restored normal function, and no obstruction was reported). Parents were satisfied with the cosmetic appearance of the wound in 91% of cases. Major complications occurred in 4% of cases. Successful repair of ureteropelvic junction obstruction in young infants can be achieved by using mini-laparotomy In Situ pyeloplasty technique with satisfactory functional and cosmetic outcomes.