Feasibility and Effectiveness of Repeat Laparoscopic Pyeloplasty for Recurrent Ureteropelvic Junction Obstruction in Pediatric Patients

Objective: To assess the outcomes of redo laparoscopic pyeloplasty (RLP) in pediatric patients with recurrent ureteropelvic junction obstruction (UPJO) in contrast to redo open pyeloplasty (ROP). In addition, evaluate the feasibility and efficacy of RLP as a treatment modality for recurrent UPJO in children. Materials and Methods: The data of 44 patients from March 2012 to March 2022, who underwent redo pyeloplasty, were retrospectively reviewed. In Group RLP, the children underwent RLP, whereas ROP was attempted in Group ROP. Demographics, clinical manifestations, surgical duration, hospitalization duration, complication rates, and treatment success were examined within the respective groups. Moreover, preoperative and postoperative measurements of anterior-posterior diameter of the renal pelvis (APD), preoperative assessment of differential renal function (DRF), and the percentage of improvement in DRF (PI-DRF) were subject to analysis. Results: The study included 28 patients who underwent RLP (Group RLP), and 16 patients who underwent ROP (Group ROP). In all cases, the Anderson-Hynes technique was employed. There was no significant difference between the two groups regarding age, body mass index, gender distribution, affected side, preoperative APD, postoperative APD, and preoperative DRF. In comparison to Group ROP, Group RLP exhibited a shorter hospitalization duration, a longer surgical procedure duration, and a higher percentage improvement in PI-DRF. The median follow-up period for Group RLP was 25 months, whereas it was 25.5 months for Group ROP. Notably, the success rates were similar between the two groups, with a success rate of 89.2% in RLP and 87.5% in ROP (p = 0.634). Conclusion: RLP has a comparable success rate to ROP and is a safe, effective, and feasible procedure for the treatment of failed pyeloplasty in children.

Pyelo-ureteral junction obstruction in poorly functioning kidneys: Does conservative management play a role in pediatric patients?

Background

Management of Pyelo-ureteral Junction Obstruction (PUJO) in poorly functioning kidneys in pediatric patients is still controversial, particularly regarding the role of conservative treatment.

Aim

To evaluate and present the outcomes of internal diversion and follow-up results of a small series of pediatric patients with UPJO in poorly functioning kidneys.

Study design

Retrospective review of 17 consecutive patients with unilateral PUJO in kidneys with Differential Renal Function (DRF) <20% undergoing temporary internal urinary diversion between 2009 and 2021 at a single tertiary center. DRF was reassessed after 1-3 months of diversion and subsequent management was conservative or surgical (pyeloplasty or nephrectomy) based on surgeon's and family's preferences without randomization.

Results

After a trial of internal urinary diversion, 4/17 patients (23%) showed a DRF increase ≥5% (9%-12%), up to a maximum DRF of 28%, 3 underwent pyeloplasty, while 1 was managed conservatively. The remaining 13 patients showed no differential renal function improvement after diversion, and 7 were managed expectantly while 6 surgically (4 pyeloplasty, 2 nephrectomy). Overall, nine patients (53%) were managed surgically and 8 (47%) expectantly After a median (range) follow-up of 3.1 (0.3-7.9) years, no significant difference was observed between groups regarding symptoms (p = 0.205), need for further surgery (p = 1.000), and renal function (p = 1.000).

Discussion

Although fraught with the limitation of a small sample size, this is the first study reporting on the conservative management of this controversial group of patients.

Conclusion

In present pediatric series of pyelo-ureteral Junction obstruction in poorly functioning kidneys with differential renal function <20%, function recovery after a trial of internal urinary diversion was quite exceptional, and no difference was observed in outcome between patients managed surgically and conservatively after stent removal.

Does Preoperative Function Affect the Outcome Following Pyeloplasty in Poorly Functioning Kidneys among Pediatric Population?

Aim:

To determine the efficacy and outcome of pyeloplasty in poorly functioning kidneys in the pediatric population and whether pyeloplasty could be offered as an upfront procedure in such patient population, instead of nephrectomy.

Materials and Methods:

A retrospective data analysis of 83 patients who underwent pyeloplasty in poorly functioning kidneys from 2010 to 2015 was performed. Success was defined based on improvement in symptoms, stable or improved function, and better drainage on post-operative Tc-99m Diethylene Triamine Pentaacetic acid scan instead of DTPA scan renography done after 3 months and yearly thereafter.

Results:

Eighty-three patients with a mean age of 6.8 ± 2.88 years with poor function on isotope renogram (<30%) were included in the study. Three patients were excluded in view of postoperative outflow obstruction. Out of the remaining 80 patients, 56 were male and 24 were female. They were divided into two groups based on preoperative differential renal function (DRF), Group I (n = 26) having preoperative DRF of <10% and Group II (n = 54) having preoperative DRF of 10%–30%. All patients underwent laparoscopic dismembered pyeloplasty with ureteral stenting. The mean DRF improved from 7.58 ± 2.39 to 29.71 ± 5.16 postoperatively in Group I. However, in Group II, DRF improved from 20.81 ± 5.68 to 37.25 ± 7.11 postoperatively. At a follow-up of 24 months, the overall success rate was 98%.

Conclusion:

Pyeloplasty gives good intermediate-term results even in extremely poorly functioning kidneys and an upfront pyeloplasty instead of nephrectomy should be offered to all pediatric patients irrespective of preoperative function.

Pyeloplasty in children with low differential renal function: Functional recoverability

INTRODUCTION AND OBJECTIVE

Ureteropelvic junction obstruction (UPJO) is a common pathology in pediatric urology practice. Indications for intervention are well established while the ideal management of children with UPJO in poorly functioning kidneys is still debatable. We aimed in this study to evaluate the outcome of pyeloplasty in patients with UPJO and low DRF ≤20%.

STUDY DESIGN

We retrospectively evaluated 218 children with congenital UPJO from two tertiary hospitals between 2008 and 2018. We included only those with primary unilateral UPJO and DRF ≤20% on diuretic renography. Open dismembered pyeloplasty with stenting was carried out in all. Patients with bilateral UPJO, solitary kidney, DRF above 20%, association with other urinary anomalies and patients who underwent previous renal or ureteric surgeries and patients with missed follow-up were excluded. Clinical and radiological outcomes of this subgroup of patients were assessed.

RESULTS

A total of 21 patients (12 boys, 9 girls) with a median age at surgery of 2 years were included. Preoperative DRF ranged from 8 to 20% with a mean of 15% ± 3.5%. The median follow-up period was 2.5 years. Renal ultrasound showed improved HN in 16 patients (4 had a complete resolution) and stable in the remaining 5. Most of the improvement was noted in the first postoperative ultrasonography 16/21 (76%). Diuretic renography showed improved DRF by 10-15% in 8 patients (38%) while the remaining patients showed stable DRF with a non-obstructive curve with a mean improvement in DRF of 8 ± 5%. No postoperative complications were encountered and none of our patients required reintervention during follow-up.

DISCUSSION

The ideal management of children with UPJO and poorly functioning kidneys is still arguable. In our study we evaluated the outcome of pyeloplasty in patients with a low DRF ≤ 20% aiming to test the patients' variables that can affect the improvement of DRF and HN grade after surgical intervention, however, none of these preoperative variables seemed to be a significant predictor.

CONCLUSIONS

Children with unilateral UPJO and DRF ≤ 20% have a favorable outcome after pyeloplasty. Improvement of HN in the first postoperative renal ultrasound is a good indicator for success.

Renal Cortical Thickness After Pyeloplasty in Pediatric Ureteropelvic Junction Obstruction

Purpose

The main goal of pyeloplasty is to maintain or improve renal function. Diuretic renography is the gold standard for evaluating renal function after pyeloplasty. Renal ultrasonography (RUS) is commonly used to determine hydronephrosis in pediatric patients. We hypothesized that the change in the renal parenchymal cortex would predict pyeloplasty success. In this study, we aim to measure renal cortical thickness change after pyeloplasty in ureteropelvic junction obstruction patients.

Materials and Methods

We retrospectively reviewed 38 patients who underwent pyeloplasty between 2005 and 2019. We divided patients into three age groups and compared the difference of renal parenchymal thickness change by using generalized estimating equations to identify associated factors for renal cortical thickness change after pyeloplasty.

Results

Thirty-nine kidney units were identified. The median age at the time of surgery was 41.61±40.99 months. Generalized estimating equations showed significant change of renal parenchymal thickness over the period of follow-up (p=0.02). The estimate of thickness change was 0.0373 mm/month. Age at the time of surgery was not associated with significant renal cortical thickness over the period of follow-up. The positive predictive factors for renal cortical thickness were creatinine clearance, pre-operative anteroposterior diameter and pre-operative renal differential function. The negative factors for decrease of renal cortical thickness were body weight, presentation with abdominal mass, and history of infection.

Conclusion

Renal cortical thickness after pyeloplasty was improved over the period of follow-up. Age at surgery was not associated with improvement of renal parenchymal thickness.

Pyeloplasty in Adults With Ureteropelvic Junction Obstruction in Poorly Functioning Kidneys: A Systematic Review

OBJECTIVES

To systematically summarize the available evidence concerning the impact of pyeloplasty on symptoms and differential renal function (DRF) in adults with unilateral UPJO in poorly functioning kidneys (PFK), and to identify potential predictors of kidney function recovery that could help clinicians select candidates for pyeloplasty.

METHODS

A literature search (MEDLINE, Embase, Google Scholar, Scopus, ClinicalTrials.gov, and the WHO Clinical Trials Registry) and systematic review were performed up to September 2020 according to the PRISMA guidelines. PFK were defined as a baseline DRF ≤30% on renal scintigraphy. The primary endpoints were symptom relief and postoperative scintigraphic DRF. Predictors of kidney function recovery were evaluated and compared among studies.

RESULTS

Nine studies comprising 731 patients met the inclusion criteria and were included for evidence synthesis. A DRF increase >5% occurred in 13.3%-53.8% of 160 patients with a pre- and postoperative renal scan. Symptoms improved in 73.3%-93.3% of 141 adults after pyeloplasty. Neither patient's age, baseline DFR, comorbidities, degree of hydronephrosis, kidney parenchymal thickness, nor kidney biopsy findings consistently predicted a significant DRF increase among 375 patients undergoing pyeloplasty.

CONCLUSION

Based on a low level of evidence, pyeloplasty may relieve symptoms and stabilize kidney function in adults with UPJO in PFK. A significant number of patients showed a DRF increase >5%, yet no consistent predictor of kidney function recovery was identified. Until more evidence becomes available, pyeloplasty could be considered for selected cases after accounting for the risks of a failure requiring a future nephrectomy.

Pyeloplasty is a safe and effective surgical approach for low functioning kidneys with ureteropelvic junction obstruction

INTRODUCTION

Indications for treatment of ureteropelvic junction obstruction (UPJO) include symptomatic obstruction, urinary tract infections, presence of an obstructive pattern on functional renal scan and/or worsening differential renal function (DRF). This paper aims to determine the relationship between preoperative DRF and surgical outcomes after pyeloplasty. We hypothesized that low preoperative DRF is not an independent predictor of pyeloplasty failure.

METHODS

A retrospective chart review was performed to identify all patients undergoing pyeloplasty for UPJO between 2008 and 2019. Patients were included only if they had at least one preoperative functional scan and a minimum of one renal ultrasound post-operatively. Patients were divided into three groups based on DRF for analysis: Group 1- 0-10%, Group 2 - >10-≤20%, Group 3 - >20%. Baseline, intraoperative and postoperative characteristics, including success and complications were compared. Additional sensitivity analyses were performed comparing patients with ≤20%, and >20% function, ≤30%, and >30% function as well as an analysis of patients undergoing only minimally invasive reconstruction.

RESULTS

Three hundred and sixty-four patients met inclusion criteria. We identified 8 patients in Group 1, 24 patients in Group 2 and 332 patients in Group 3. Mean procedure time was longest for the ≤10% function group (237.9 vs 206.4 vs 189.1; p = 0.01). We found no difference in 30-day post-operative complications, overall success rate or the need for additional procedures among the three groups. For patients in Group 1, we noted variation in the post-procedure DRF with a range of -2.8 to +47% change. In this group, none of patients with low DRF underwent nephrectomy. Multivariate logistic regression did not identify renal function as a predictor of operative success OR 1.00 (95% CI: 0.97-1.03) (p-value: 0.88).

DISCUSSION

The results of the present study suggest that low DRF alone is not associated with worse outcomes and shows no difference in the failure rate. The incidence and type of complications were not increased for the lower functioning groups. The main limitation of this study would be its retrospective nature and single-institution experience. Furthermore, post-operative functional studies were not available for all patients, limiting the ability to draw conclusions on the change in DRF after surgery.

CONCLUSIONS

In a large cohort, preoperative DRF was not predictive of pyeloplasty success rate. DRF ≤10% was not associated with higher incidence of complications or failure rate. The DRF alone should not dictate the management options available for patients with UPJO.

Physician perspectives on discussions with parents of infants with suspected ureteropelvic junction obstruction

INTRODUCTION

The purpose of this study was to understand pediatric urologists' perceived role of patient characteristics on discussions about treatment of infants with suspected UPJ obstruction.

METHODS

We conducted semi-structured interviews with pediatric urologists from three geographically diverse sites. Interview domains included: clinical indications for surgery, discussions with parents, and consideration of parent socioeconomic factors. Transcribed data and field notes were analyzed using a team-based, inductive grounded theory approach.

RESULTS

Thirteen physicians were interviewed. Physicians reported a standardized approach to discussions to facilitate parental understanding. While they did not report overt consideration of demographics, they tailored discussions based on educational and cultural background and language barriers. Physicians also reported that concerns about risk of loss to follow up contributed to their treatment recommendations. Most physicians recognized that the lack of clear data often led to use of personal experience to guide recommendations.

CONCLUSION

Physicians recognize a gap in data to guide surgical decisions and utilize personal experience to augment this gap. They also recognize the influence of educational and language barriers on discussions with families and consider risk of loss to follow up when making recommendations, suggesting an implicit consideration of demographics. These findings suggest that development of evidence-based guidelines may reduce treatment variations.

LEVEL OF EVIDENCE

Not applicable (qualitative research study written in compliance with COREQ guidelines).

Does relative renal function improve after intervention for chronic ureteric obstruction?

Introduction

Unilateral renal function often deteriorates with chronic ureteric obstruction. Our objectives were to determine the change in relative renal function (RRF) by MAG3 renography after intervention for ureteric obstruction, and to identify clinical/epidemiological factors which influence long-term outcomes.

Material and methods

We identified 228 patients from 2006 to 2017 who underwent MAG3 renography before and after intervention for unilateral ureteric obstruction. Patients were grouped into categories preoperatively - with normal RRF (43–57%) through mild (29–42%), moderate (15–28%) and severe (<15%) impairment of RRF. Patient demographics, types of obstructive uropathy and intervention employed were analysed. Each group was assessed for the absolute change in RRF and change in RRF category postoperatively.

Results

The mean patient age was 50.4 years (SD 16.7), and 62.3% were female. Overall, the mean pre- and post-intervention RRF of the obstructed kidney did not differ significantly (32.30% vs. 32.20%, P = 0.835). Most patients remained in their preoperative RRF group: 85.9% of normal, 67.4% of mild, 64.4% of moderate and 73.3% of patients with severe RRF impairment did not change category.

Patients with mildly impaired preoperative RRF showed a significant worsening postoperatively (36.37% vs. 34.58%, P = 0.024). The other three groups showed no significant change in RRF following intervention.

Multivariate logistic regression analysis showed no statistically significant association between type of intervention, age, gender or diagnosis and improvement in postoperative RRF category.

Conclusions

Our results show that RRF does not improve significantly after intervention for ureteric obstruction. The aim should therefore be to maintain existing renal function and relieve symptoms.

Impact of successful pediatric ureteropelvic junction obstruction surgery on urinary HIP/PAP and BD-1 levels

INTRODUCTION

In the pediatric patient whose ureteropelvic junction obstruction (UPJO) is not always symptomatic, imaging is the most common means of detecting surgical success. There is interest, however, in other means of post-operative monitoring. A panel of antimicrobial peptides (AMPs) has been previously found to be elevated in UPJO, but the impact of surgical correction on these AMPs is unknown.

OBJECTIVE

To determine if elevated levels of candidate urinary AMP biomarkers of urinary tract obstruction decrease following UPJO repair.

STUDY DESIGN

Pediatric patients undergoing surgical correction of an UPJO were recruited for participation. Bladder urine from uninfected consenting/assenting patients was collected immediately prior to surgery and then at least 6 months afterward. Based on prior studies demonstrating significant elevation of beta defensin 1 (BD-1), hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), cathelicidin (LL-37), and neutrophil gelatinase-associated lipocalin (NGAL) in patients with UPJO versus control patients, we performed enzyme-linked immunosorbent assays on these four AMPs to compare their expression before and after surgical intervention. If found to significantly decrease, AMP levels were compared to healthy controls. AMP levels were normalized to urine creatinine. Results were analyzed with paired t test or Wilcoxon test using Graphpad software. Correlation was calculated using Pearson or Spearman correlation. A p-value of <0.05 was considered significant.

RESULTS

13 UPJO patients were included in this study; 9 were male (69%). Age at surgery was a median of 4.3 years (average 6.1, range 0.4-18.4 years). Follow-up urine samples were collected a median of 27.4 months after surgery (average 27.4; range 7.8-45.3 months). All 13 patients had clinical improvement and/or signs of improved hydronephrosis on post-operative imaging. HIP/PAP and BD-1 significantly decreased in post-surgical samples compared to pre-surgical samples (p = 0.02 and 0.01, respectively); NGAL and LL-37 did not significantly change. Overall, HIP/PAP decreased in 12 patients (92%) and BD-1 decreased in 11 patients (85%). BD-1 levels after successful repair were not different from healthy controls (p = 0.06).

DISCUSSION

Urinary biomarkers of obstruction should detect significant obstructive pathology as well as reflect its resolution. This would enable their use in post-operative monitoring and augment current methods of determining successful surgical outcome through imaging.

CONCLUSIONS

The AMPs HIP/PAP and BD-1 are significantly elevated in UPJO but then significantly decrease after pyeloplasty, with BD-1 returning to healthy control levels. As a result, these AMPs could serve as markers of successful surgical intervention.

Laparoscopic pyeloplasty as an alternative to nephrectomy in adults with poorly functioning kidneys due to ureteropelvic junction obstruction

OBJECTIVES

To evaluate outcomes of laparoscopic pyeloplasty (LP) in adults with poorly functioning kidney due to ureteropelvic junction obstruction (UPJO).

METHODS

A retrospective comparative analysis was performed between adult patients who underwent LP due to UPJO with differential renal function (DRF) ≤ 15% and DRF > 15%. LP success rate and complications were assessed. LP success was defined as symptoms improvement and DRF improvement or stabilization. DRF and estimated glomerular filtration rate (eGFR) were analyzed before and 12 months after surgery to evaluate renal function recovery. DRF was estimated using Tc-99 m DMSA renal scintigraphy.

RESULTS

Among 121 LP performed in the study period at our institution, 15 and 42 were included in the DRF ≤ 15% and DRF > 15% groups, respectively. At a median follow-up of 17.8 months, all patients with DRF ≤ 15% reported symptoms improvement. LP success rate was 86.7% and 90.5% (p = 0.65) for patients with DRF ≤ 15% and DRF > 15%, respectively. There were no complications in the DRF ≤ 15% group, while there were three complications recorded in the DRF > 15% group (Clavien 2 and 3b). In the DRF ≤ 15% group, mean pre-operative and post-operative DRF was 9.5% ± 3.6 and 10.5% ± 7.8 (p = 0.49), respectively. Median pre-operative and post-operative eGFR was 68.5 ml/min and 79.8 ml/min (p = 0.93), respectively. Two patients had DRF improvement after LP.

CONCLUSIONS

LP in adult patients with UPJO and poor function kidneys is an effective and safe procedure. DRF recovery is seen in a minority of the patients; however, LP is an alternative to nephrectomy.

Changes in differential renal function after pyeloplasty in infants and children

INTRODUCTION

Ureteropelvic junction obstruction (UPJO) is one of the most common causes of hydronephrosis in pediatric populations. Many need surgical intervention. The aim of surgery is preserving renal function and reducing symptoms such as urinary tract infections and pain.

OBJECTIVES

The objectives were to evaluate differential renal function (DRF) in infants and children after surgery for UPJO and to identify factors predicting postoperative improvement. The difference in outcomes between patients with antenatal hydronephrosis and those diagnosed later was evaluated.

STUDY DESIGN

A total of 85 children (63 boys and 22 girls) aged 0-16 years, treated for UPJO with dismembered pyeloplasty, were followed up as per a structured protocol including ultrasounds and renal scans (MAG-3) pre-operatively and three and 18 months postoperatively. Five children with bilateral or single kidney UPJO were excluded. Patient records were retrospectively reviewed, and the patients were grouped as per prenatal (group 1, n = 23) or postnatal (group 2, n = 57) diagnosis. Univariable and multivariable logistic regression analyses searching for factors predicting >5% postoperative improvement in DRF on the obstructed side were performed. Factors included in analyses were age at diagnosis and surgery, sex, type of presentation, cause of obstruction, estimated glomerular filtration rate, pre-operative DRF, anteroposterior diameter (APD), APD/renal parenchymal thickness, and grade of hydronephrosis as per the Onen alternative grading system (grade 1-4).

RESULTS

Pre-operative DRF on the obstructed side was a mean of 42% (standard deviation, 12), with no difference between the groups. The median age at surgery was 0.9 (0.2-10) and 8.1 (0.6-16) years in groups 1 and 2, respectively (P < 0.001). The majority had unchanged DRF 18 months postoperatively, 19 (27%) patients improved by >5%, and one deteriorated. The proportion of patients with improved DRF was higher in group 1 (n = 10; 45%, P = 0.026). Anteroposterior diameter, APD/parenchymal thickness, pre-operative DRF, and antenatal diagnosis were predictors in the univariable analyses, and high APD (odds ratio [OR] = 1.1, P = 0.0023), antenatal diagnosis (OR = 0.23, P = 0.048), and low pre-operative DRF (OR = 0.90, P = 0.0045) built the best model of independent factors predicting improvement in DRF in multivariable analyses (Summary Figure).

DISCUSSION

The limitation of the study is that it is retrospective, but it has the advantage of a uniform follow-up protocol, including patients from a five-year period, with few lost to follow-up. The results can be of interest in evaluating factors of importance for predicting recovery of function in obstructive uropathies in children.

CONCLUSION

The majority of children had preserved or improved function after surgery for UPJO. Those with an antenatal diagnosis displayed a greater ability to catch up in DRF, and high APD, antenatal diagnosis, and low pre-operative DRF were independent predictive factors of an improvement in renal function after pyeloplasty.

Ultrasound-Based Scoring System for Indication of Pyeloplasty in Patients With UPJO-Like Hydronephrosis

Background: Previous scoring systems have used renal scan parameters to assess severity of ureteropelvic junction obstruction-like hydronephrosis (UPJO-like HN), however this information is not always reliable due to protocol variation across centers and renogram limitations. Therefore, we sought to evaluate the Pyeloplasty Prediction Score (PPS), which utilizes only baseline ultrasound measurements to predict the likelihood of pyeloplasty in infants with UPJO-like. Methods: PPS was developed using three ultrasound parameters, Society of Fetal Urology (SFU) grade, transverse anteroposterior (APD), and the absolute percentage difference of ipsilateral and contralateral renal lengths at baseline. PPS was evaluated using prospectively collected prenatal hydronephrosis data (n = 928) of patients with UPJO-HN. Children with vesicoureteral reflux. primary megaureter, other associated anomalies, bilateral HN and <3 months of follow-up were excluded. Scores were analyzed regarding its usefulness in predicting which patients would be more likely to undergo pyeloplasty. Sensitivity, specificity, likelihood ratios (LR) and receiver operating characteristic (ROC) curve were determined. Results: Of 353 patients, 275 (78%) were male, 268 (76%) had left UPJO-like HN, and 81 (23%) had a pyeloplasty. The median age at baseline was 3 months (IQR 1-5). The PPS system was highly accurate in distinguishing patients who underwent pyeloplasty using baseline ultrasound measurements (AUC: 0.902). PPS of 7 and 8 were found to have a sensitivity of 85 and 78%, and specificity of 81 and 90%, respectively. PPS of 8 was associated with a LR of 7.8, indicating that these patients were eight times more likely to undergo pyeloplasty. Conclusion: Overall, PPS could detect patients more likely to undergo pyeloplasty using baseline ultrasound measurements. Those with a PPS of eight or higher were eight times more likely to undergo pyeloplasty.

Pyeloplasty vs. nephrectomy for ureteropelvic junction obstruction in poorly functioning kidneys (differential renal function <20%): a multicentric study

INTRODUCTION

Management of poorly functioning kidneys with ureteropelvic junction obstruction (UPJO) is controversial, with some recommending direct nephrectomy and others direct pyeloplasty, and others temporary diversion. This study aimed to determine whether pyeloplasty is associated with higher complication rate than nephrectomy under these circumstances and whether it allows for functional recovery.

METHODS

A retrospective review of 77 patients undergoing surgery for UPJO associated with a differential renal function (DRF) < 20% at 4 centres between January 2000 and December 2015 was conducted. Short- and long-term complications between pyeloplasties (n = 47) and nephrectomies (n = 16) and the changes in the DRF after pyeloplasty were compared.

RESULTS

Patients undergoing nephrectomy had significantly lower median pre-operative DRF (p < 0.001) and were significantly more likely to undergo a minimally invasive approach (p = 0.002) than those undergoing pyeloplasty. No postoperative variable was statistically different between groups. After a mean follow-up of 63 (10-248) months, no statistically significant difference was found in intra-operative, early, late, and overall complications between pyeloplasty and nephrectomy. Pyeloplasty failed in 3% (2/62) of cases. Of the patients undergoing successful pyeloplasty, 36 had a pre-operative and a postoperative renogram, and functional recovery >5% was observed in 13 (36%), whereas the DRF remained unchanged in 16 (45%). Only postnatal diagnosis was associated with a significantly higher chance of functional recovery (odds ratio [OR] = 4.13, p = 0.047).

DISCUSSION

Nephrectomy was more commonly performed using a minimally invasive approach and required less-intense follow-up than pyeloplasty. Moreover, complications after pyeloplasty, although occasional, required additional surgery which was never required after nephrectomy. Moreover, it should be considered that conservative treatment might be a third option in some of these patients.

CONCLUSIONS

In the study patients, pyeloplasty was not associated with significantly higher morbidity than nephrectomy. Need for deferred nephrectomy seems exceptional in decompressed kidneys even though renal function remains poor. Of the pyeloplasty cases not requiring additional surgery, one-third showed an improvement in DRF and a postnatal diagnosis was the only predictive factor for renal functional recovery.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview

In the context of ante-natally diagnosed hydronephrosis, the vast majority of children with a dilated renal pelvis do not need any surgical treatment, as the dilatation resolves spontaneously with time. Slow drainage demonstrated at Tc-99m-mercaptoacetyltriglycine (MAG3) renography does not necessarily mean obstruction. Obstruction is defined as resistance to urinary outflow with urinary stasis at the level of the pelvic-ureteric junction (PUJ) which, if left untreated, will damage the kidney. Unfortunately this definition is retrospective and not clinically helpful. Therefore, the identification of the kidney at risk of losing function in an asymptomatic patient is a major research goal. In the context of renovascular hypertension a DMSA scan can be useful before and after revascularisation procedures (angioplasty or surgery) to assess for gain in kidney function. Renal calculi are increasingly frequent in children. Whilst the vast majority of patients with renal stones do not need functional imaging, DMSA scans with SPECT and a low dose limited CT can be very helpful in the case of complex renal calculi. Congenital renal anomalies such as duplex kidneys, horseshoe kidneys, crossed-fused kidneys and multi-cystic dysplastic kidneys greatly benefit from functional imaging to identify regional parenchymal function, thus directing further management. Positron emission tomography (PET) is being actively tested in genito-urinary malignancies. Encouraging initial reports suggest that F-18-fluorodeoxyglucose (FDG) PET is more sensitive than CT in the assessment of lymph nodal metastases in patients with genito-urinary sarcomas; an increased sensitivity in comparison to isotope bone scans for skeletal metastatic disease has also been reported. Further evaluation is necessary, especially with the promising advent of PET/MRI scanners. Nuclear Medicine in paediatric nephro-urology has stood the test of time and is opening up to new exciting developments.

The role of urinary KIM-1, NGAL, CA19-9 and β2-microglobulin in the assessment of ureteropelvic junction obstruction in adults

PURPOSE

The objective of this study is to evaluate the diagnostic properties of urinary biomarkers in adults with ureteropelvic junction obstruction: KIM-1, NGAL, CA19-9, and β2-microglobulin. We also assessed urinary biomarker concentrations following pyeloplasty.

MATERIAL AND METHODS

We prospectively studied adults from December 2013 to February 2015. We included 47 patients with a mean age of 38.6 ± 12.7 years. Each patient provided four samples of voided urine for biomarker measurement, one at pre-operative consultation and the others at 1, 3, and 6 months of post-operative follow-up. The control group consisted of 40 healthy individuals with no hydronephrosis on ultrasound evaluation.

RESULTS

KIM-1 had an area under the curve of 0.79 (95% CI 0.70-0.89), NGAL 0.71 (95% CI 0.61-0.83), CA19-9 0.70 (95% CI 0.60-0.81), and β2-microgloblin 0.61 (95% CI 0.50-0.73). KIM-1 was the most sensitive marker with a cut-off of 170.4 pg/mg creatinine (sensitivity 91.4%, specificity 59.1%), whereas CA19-9 was the most specific with a cut-off of 51.3 U/mg creatinine (sensitivity 48.9%, specificity 88.0%). Urinary concentrations of biomarkers decreased after pyeloplasty.

CONCLUSIONS

The evaluation of urinary biomarkers is useful in adults undergoing pyeloplasty. KIM-1, NGAL, and CA19-9 were elevated and significantly decreased after surgery.

Percent improvement in renal pelvis antero-posterior diameter (PI-APD): Prospective validation and further exploration of cut-off values that predict success after pediatric pyeloplasty supporting safe monitoring with ultrasound alone

INTRODUCTION

Renograms are frequently obtained post-pyeloplasty in patients with residual hydronephrosis to confirm adequate drainage. Recent evidence suggests that percent improvement in antero-posterior diameter (PI-APD) ≥38 is predictive of success. We sought to further explore PI-APD ranges that would allow identification of patients who would benefit from ultrasound (US) monitoring alone vs. post-operative renal scan, and those more likely to develop recurrent ureteropelvic junction obstruction (rUPJO).

METHODS

A single-center prospectively-collected pyeloplasty database (2008-2015) was queried (n = 151). Only patients with both pre- and post-operative APD measurements were included (n = 138). PI-APD was divided into 3 categories: <20%; 20-39%; ≥40%. The following variables were collected post-operatively: patients monitored with US alone, renogram and US, rUPJO and minimal or resolved hydronephrosis (SFU ≤2; UTD ≤1; APD ≤15 mm).

RESULTS

Mean age at first and last follow-up were 4.8 (median 4.0; range 0-60) months and 26.6 (median 20.5; range 1-77) months, respectively. Of 138 patients, 84 (61%) had US alone, 54 (39%) had a renogram and US post-operatively, and 6 (4%) developed rUPJO. Of 84 patients who had US alone, 71 (84%; p < 0.01) demonstrated ≥40% PI-APD. Of 54 patients with renogram and US 46 (85%; p < 0.01) had ≥40 PI-APD. Of the 6 patients who developed rUPJO, all were in the <20 PI-APD group (100%; p < 0.01). Resolution of hydronephrosis according to SFU, UTD and APD occurred in 96/138 (70%), 89/138 (64%) and 113/138 (82%) patients respectively. Of these, 87 (91%), 81 (91%), and 108 (95%) occurred in >40% PI-APD group.

CONCLUSION

≥40% PI-APD at the first post-operative visit strongly predicts pyeloplasty success, as up to 82% of these patients showed resolved hydronephrosis and 61% underwent non-invasive monitoring by US alone. Our data suggests that up to 85% of renograms may have been unnecessary. Finally, <20% PI-APD permitted identification of all rUPJO cases. Stratification of patients based in PI-APD is a promising strategy for further minimizing radiation exposure while safely detecting children at risk for rUPJO.

Therapeutic approaches and long-term follow-up for prenatal hydronephrosis

Objective:

This study summarises the outcomes of 149 patients who underwent surgery for antenatally diagnosed unilateral hydronephrosis.

Methods:

The medical records of such patients over a 23-year period were reviewed retrospectively. Age at the time of operation, preoperative and postoperative mean pelvic diameter on ultrasound, split renal function, washout patterns on scintigraphy, and early and late complications were recorded.

Results:

The mean preoperative follow-up period was five months (range: 1–66 months). One patient was operated on after 12 months and two patients after five years of follow-up. Mean preoperative pelvic diameter and renal function were 30.8 mm and 38.6%, respectively; all patients had an obstructive wash-out pattern. In the postoperative period, the corresponding measurements were 11.7 mm and 39.2%, with 111 non-obstructive, 24 partially obstructive, and 14 obstructive wash-out patterns. Three patients with severe caliectasis and low renal function underwent surgery despite mild hydronephrosis. The mean postoperative follow-up period was six (range 4–11) years. Complications developed in 14 (9.3%) patients.

Conclusion:

Patients with antenatal hydronephrosis may need surgery even after a follow-up period of six years. Because of the potential late development of complications, postoperative follow-up should be continued for 10 years.

Gravity-assisted drainage imaging in the assessment of pediatric hydronephrosis

INTRODUCTION

As early detection of hydronephrosis increases, we require better methods of distinguishing between pediatric patients who require pyeloplasty vs. those with transient obstruction. Gravity-assisted drainage (GAD) as part of a standardized diuretic renography protocol has been suggested as a simple and safe method to differentiate patients.

METHODS

Renal scans of 89 subjects with 121 hydronephrotic renal units between January 2004 and March 2007 were identified and analyzed.

RESULTS

Of all renal units, 65% showed obstruction. GAD maneuver resulted in significant residual tracer drainage in eight renal units, moderate drainage in 12 renal units, and some improvement in 40 units after the GAD maneuver. Of the eight renal units with significant residual tracer drainage, only two proceeded to pyeloplasty. After pyeloplasty, nine children had improved time to half maximum (T(1/2) Max) and 13 were unchanged.

CONCLUSIONS

Our study was limited due to its retrospective design and descriptive analyses, but includes a sufficient number of subjects to conclude that GAD as part of a diuretic renography protocol is an effective and simple technique that can help prevent unnecessary surgical procedures in pediatric patients.

Is decreased diameter of renal pelvis in prone position an indicator of successful pyeloplasty?

OBJECTIVE

To evaluate patients who had undergone pyeloplasty for pelviureteric junction obstruction, by measuring the anteroposterior diameter (APD) of the renal pelvis in supine and prone positions, and determine whether a decrease in APD in prone position can exclude obstruction in dilated renal system.

MATERIALS AND METHODS

From January 2012 to December 2013, patients who had undergone pyeloplasty were evaluated by ultrasound in two centers. The difference of APD of the renal pelvis in supine and prone positions was obtained. Correlation was made with the pre- and post-pyeloplasty renal function by radionuclide renogram.

RESULTS

There were 42 patients (31 males, 11 females; age range 5 months to 18 years). Residual hydronephrosis was detected in 41 patients of whom 35 patients (85%) showed decrease in APD by >10% in prone position. These patients and the one without hydronephrosis showed either no deterioration or improvement in renal function. Six patients (15%) showed either no change or increase in APD in prone position. Three patients (7.5%) were confirmed to have decrease in renal function indicating obstruction. Three patients (7.5%) showed no deterioration of renal function, but sluggish drainage on radionuclide renogram.

CONCLUSION

Demonstration of decreased APD of renal pelvis in prone position by ultrasound is useful to differentiate obstructed from non-obstructed dilated renal system, and it correctly identified 85% candidates with successful pyeloplasty. In patients with no decrease or increase in APD at prone position, further follow-up is recommended to rule out obstruction.

Functional outcomes of early versus delayed pyeloplasty in prenatally diagnosed pelvi-ureteric junction obstruction

Although initial conservative management is popular in the management of antenatally detected pelvi ureteric junction (PUJ) obstruction [1-3], several authors [4,5] have questioned this approach and expressed concern about failure to recover the function lost during expectant management following surgery. In this single center prospective study, we have compared the functional outcomes following early versus delayed pyeloplasty in SFU grade 3-4 PUJ obstruction.

METHODS

Among those children, who presented between 2004 and 2013, with prenatal diagnoses of unilateral PUJ obstruction (n = 886), those with SFU grade 1 or 2 hydronephrosis on USG (n = 533) were excluded. In the remaining 353 children with SFU grade 3 and 4 hydronephrosis, 243 had obstructive pattern on radionuclide scan. After excluding those with severely impaired or supranormal split renal function (SRF), palpable mass, single kidney status, bilateral disease and associated other urological anomalies a total of 126 children were included in the study group. Parents who were unwilling for a frequent follow-up underwent early pyeloplasty, (Group I: n = 62) while the remaining underwent initial conservative management, with 3 monthly USG and nuclear scans (Group II; n = 64). In this group pyeloplasty was performed whenever there was deterioration in SRF >10%, or urine infection or pain during the follow-up. A standard open dismembered pyeloplasty was performed by the same surgeon in all patients. Radionuclide scan was performed at 1 year, at the same center using the same protocol, to assess final SRF and drainage. The functional outcomes were compared using student's t test and chi square test.

RESULTS

Group I comprised of 62 patients while Group II 64 patients. The mean age at pyeloplasty was 2.8 months in group I while 12.5 months in group II. There was no significant difference in the initial antero posterior diameter (APD) between the groups; 30.2 (±3.2) mm in group I and 29.6 (±3.7) mm in group II. At 1-year follow up after surgery, there was improvement in the APD, 16.8 (±4.2) mm in group I and 18.2 (±4.5) mm in group II, with no significant difference between them. In group I, the initial mean SRF was 34.1% (±6.4) and there was significant improvement (p = 0.01) in mean SRF to 37.2 (±7.1) at 1-year follow up after surgery. In group II, the mean SRF was 35.9 (5.7) initially and there was a deterioration to 32.6 (±5.5) before surgery (Figure). At 1-year follow up after surgery, there was a marginal improvement to 33.5 (5.6), however it was significantly lower compared to the initial SRF (p = 0.01). Compared to initial function, at 1-year follow up after pyeloplasty, SRF improved in significantly higher number of patients; 17/62 (27.4%) in group I while only 7/64 (10.9%) in group II (p = 0.03) (Table). There was significantly fewer patients with deterioration in final SRF at 8/62 (12.9%) in group I compared to 22/64 (34.4%) in group II (p = 0.03).

DISCUSSION

Although several publications [1-3] have reported functional recovery during initial conservative treatment of PUJ obstruction, in our study a large proportion of patients (80%) in Group II had loss of function during follow-up. This is probably because the study population included only SFU grade 3-4 with obstructive renogram. Several authors have expressed concern about irreversible loss of renal function during expectant management [4,5]. Findings of our study reveal that irrespective of initial SRF, early pyeloplasty in prenatally diagnosed SFU grade 3-4 PUJ obstruction leads to significant improvement of SRF, while delayed pyeloplasty leads to a marginal but, significant loss. This fact should be highlighted to parents so that informed decisions can be made regarding early versus delayed surgery.

An analysis of long-term occurrence of renal complications following pediatric pyeloplasty

OBJECTIVE

Few reports discuss post-pubertal renal complications after pyeloplasty. We analyzed long-term complications, such as decreased renal function (RF) measured by serum creatinine (SCr), hypertension (HTN), or proteinuria (protU) following pediatric pyeloplasty.

SUBJECTS AND METHODS

We retrospectively investigated 257 patients who underwent dismembered pyeloplasty due to ureteropelvic junction obstruction from January 1986 to December 2001. Medical history, preoperative and postoperative blood pressure, urinalysis, and SCr results were reviewed.

RESULTS

Fifty-five patients (47 male, 8 female) who were followed up for at least 10 years with post-pubertal follow-up data available were analyzed. Seven (12.7%) patients were diagnosed with HTN, and 10 (18.2%) with protU. The grade of hydronephrosis decreased, and the differential RF measured by MAG-3 renal scan significantly increased at final analysis (p<0.001). Presence of preoperative symptoms (p=0.034), and SCr elevation (p=0.018) showed correlation with HTN. HTN took 15.7 (±5.8) (7-25) years, and protU detection took 16.2 (±5.9) (6-23) years, with the highest incidence of both HTN and protU between 15 and 20 years postoperatively.

CONCLUSION

According to our investigation, a prudent evaluation of signs of RF decrease at 10 years after surgery, and then every 5 years, until 20 years should be recommended, although further studies are necessary.

The risk factors and clinical significance of acute postoperative complications after unstented pediatric pyeloplasty: a single surgeon's experience

PURPOSE

To analyze the risk factors and clinical significance of postoperative complications after unstented pediatric pyeloplasty.

MATERIALS AND METHODS

We analyzed 285 kidney units (KUs) on which unstented pyeloplasty was performed between April 2002 and March 2010. Measures included preoperative factors, postoperative complications, change in postoperative differential renal function (DRF), and failure of pyeloplasty. Risk factors for acute complications requiring additional ureteral stenting and decreased DRF were analyzed.

RESULTS

During a median follow-up period of 67.0 months, an additional ureteral stenting was required in 28 KUs (9.8%) due to the development of acute postoperative complications after unstented pyeloplasty. The incidence of complications increased significantly as preoperative DRF increased. DRF of more than 60% was the only independent risk factor for acute complications. Postoperative decrease in DRF was observed in 58 KUs (22.4%) among 259 KUs analyzed. Pyeloplasty failure was observed in 10 KUs (3.5%). The development of acute complications was not a risk factor for a decrease in DRF or pyeloplasty failure.

CONCLUSIONS

Urinary diversion during pyeloplasty is not related to a decrease in DRF or pyeloplasty failure. However, in patients with a preoperative DRF of greater than 60%, diversion could be considered due to the high prevalence of complications.

Time course of hydronephrotic changes following unilateral pyeloplasty

OBJECTIVES

The temporal pattern of hydronephrotic change following pyeloplasty has not been well defined. To address this issue, 23 years of postpyeloplasty follow-up data from a single surgeon were analyzed.

PATIENTS AND METHODS

Records of dismembered pyeloplasty from 1986 to 2004 were retrospectively reviewed. Ultrasound follow-ups were conducted at 3-6-month intervals after surgery for up to 3 years, and were then extended to either annually or biannually until the completion of puberty. Overall outcome of hydronephrosis (HN), timing of initial improvement and normalization were determined. Factors associated with these changes were examined.

RESULTS

Of 215 patients who completed follow-up of at least 5 years, about 80% experienced either normalization or improvement. Once they had shown improvement of HN during follow-up, no recurrence was observed. The median time for recognition of initial improvement and normalization of HN was 8 months and 41 months after surgery, respectively. Multivariate analysis revealed that the presence of immediate postoperative obstruction was a negative factor for initial improvement. Symptomatic presentation and no initial improvement until 6 months after pyeloplasty turned out to be negative factors for normalization.

CONCLUSIONS

The results confirm the excellent long-term outcome of pyeloplasty, and highlight the importance of frequent ultrasound until initial improvement of HN, when subsequent ultrasound follow-ups may be safely omitted to focus on follow-up of renal function, proteinuria and hypertension.

Long-term results of pyeloplasty in poorly functioning kidneys in the pediatric age group

OBJECTIVE

To determine the efficacy and long-term outcome of pyeloplasty in poorly functioning kidneys in the pediatric age group.

METHOD

Retrospective data analysis was performed on patients who underwent pyeloplasty in 2000-2008. The parameter analyzed was postoperative outcome. Success was defined on the basis of either improvement in symptoms or better drainage on postoperative Tc-99m DTPA renography done after 3 months and yearly thereafter.

RESULTS

A total of 39 patients with a mean age of 8.6 years (4 months to 13 years), and male to female ratio of 3:1, with poor function on isotope renogram (<30%) were included in the study. Left to right side ratio was 1.3:1. Dismembered pyeloplasty was done in all patients. Laparoscopic pyeloplasty was done in 27 (66.7%) and open in 12 (33.3%) patients. Follow-up renograms were available for 35 patients: 31 showed improvement in drainage and no further deterioration in renal function and 4 showed an obstructed pattern; of these, two patients had significant deterioration in split function and the other two underwent redo pyeloplasty by open technique. At a mean follow up of 41.6 months (8-75), overall success rate was 90%.

CONCLUSION

Pyeloplasty gives good intermediate-term results in poorly functioning kidneys in the pediatric age group.

Relative renal function does not improve after relieving chronic renal obstruction

Study Type - Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Technetium-99m MAG3 renography can be used to quantify relative renal function (RRF). Deterioration of renal function occurs with chronic obstruction. Small studies have previously shown that RRF is not improved in adult patients after pyeloplasty. Some studies have suggested that patients with higher preoperative RRF are more likely to improve. To our knowledge, these data represent the largest review of cases related to this subject. This study verifies past studies' assertions that RRF does not improve after relief of chronic renal obstruction. Using multivariable analysis, we identify lower age and lower preoperative RRF as predictors of >7% improvement in RRF. These data suggest that the aim of relieving obstruction should be to maintain RRF and alleviate symptoms, but not to seek improvement in overall renal function.

OBJECTIVE

To determine the change in relative renal function (RRF) after relief of chronic obstruction in adults.

PATIENTS AND METHODS

We retrospectively identified 85 adult patients who underwent scintigraphic diuretic renography before and after an intervention to relieve chronic unilateral renal obstruction. Patients were stratified into groups of low (<20%), medium (20-40%) and high (>40%) preoperative RRF in the obstructed kidney. Each group was assessed for change in RRF after relief of obstruction. We performed multivariable logistic regression analysis to determine whether age and pre-procedural RRF predicted a >7% improvement in RRF, controlling for medical comorbidities and type of obstruction.

RESULTS

The mean (sd) patient age was 43.6 (16.8) years and 66% of patients were female. The mean (sd) pre- and postoperative RRF values were not significantly different (37.6 [12.3] % vs 38.4 [13.6] %; P = 0.31). Patients stratified by low, medium and high preoperative function showed no significant change in postoperative RRF (P = 0.53, 0.39 and 0.77, respectively). In multivariable logistic regression analysis, younger age (odds ratio [OR] 0.90, 95% confidence interval [CI] 0.83-0.98) and lower preoperative RRF (OR 0.90, 95% CI 0.83-0.97) predicted improvement in RRF of >7%, after adjustment.

CONCLUSIONS

RRF does not significantly increase after relief of chronic obstruction. The goals of relieving chronic renal obstruction should be to maintain renal function and relieve symptoms, but not to regain renal function.

When is it necessary to perform nuclear renogram in patients with a unilateral neonatal hydronephrosis?

PURPOSE

To examine whether anteroposterior(AP) pelvic diameter on postnatal renal ultrasound scan (US) can predict both initial differential renal function (DRF) and deterioration in DRF in patients with prenatally diagnosed hydronephrosis.

METHODS

One hundred and thirty-three patients diagnosed with a unilateral prenatal hydronephrosis, confirmed postnatally, were evaluated. We tried to find the cutoff values for initial AP diameter and change in AP diameter based on initial DRF and renal outcome. Reduction of 5% or more was considered as deterioration in function. All patients had an initial US scan at a mean age of 1.62 weeks (1-4) and nuclear renogram at 13.24 weeks (7-21). All patients had a second US at a mean age of 10.58 weeks (6-19). 119 patients had a second renogram.

RESULTS

Initial mean pelvic diameter was 20.86 (11-49) mm. When AP pelvic diameter was less than 20 mm, 98.6% of all renal units had a function of ≥40%. The cutoff point for AP pelvic diameter was 19.05 when DRF was ≥45% (P < 0.001). When the reduction in hydronephrosis in pelvic diameter was analyzed to predict the initial renal function, a cutoff point of 1.3 mm decrease was found when initial renal function was ≥40% (P < 0.001). The reduction in AP pelvic diameter was 2.1 mm when initial DRF was ≥45% (P = 0.009). For all patients except 3 individuals, if there was a reduction in AP diameter or the AP diameter was stable, then no reduction in function was observed.

CONCLUSION

When the AP pelvic diameter is less than 20 mm at presentation, DRF is normal. If the AP diameter is stable or decreases, there is unlikely to be a significant deterioration in renal function. Consequently, in selected patients, congenital unilateral hydronephrosis can be followed with serial ultrasounds.

Screening ultrasound in follow-up after pediatric pyeloplasty

OBJECTIVES

To investigate whether an initial ultrasound (US) adequately identifies those patients who need further investigation and possibly intervention while decreasing instrumentation and radiation exposure. The recommended imaging after pediatric pyeloplasty has included intravenous pyelography, radionucleotide renography, and ultrasound US.

METHODS

We retrospectively reviewed pediatric open pyeloplasty cases performed between 1999 and 2007. Of 116 patients reviewed, 49 met the inclusion criteria of unilateral pyeloplasty with pre- and postoperative US and mercaptoacetyltriglycine (MAG-3). Hydronephrosis was judged by anterior posterior pelvic diameter and caliectasis. Change in renal function on MAG-3 was defined as increase or decrease in function >5%.

RESULTS

Of 49 patients, 42 (85.7%) showed improved or stable hydronephrosis postoperatively and 7 (14.3%) showed increased hydronephrosis. Forty-six (93.8%) patients had either improved or stable renal function. Of 42 patients with stable or improved hydronephrosis, 41 (97.6%) also had stable or improved function. Comparatively, of 7 patients with increasing hydronephrosis, 2 (28.6%) showed deteriorated renal function, P = .05.

CONCLUSIONS

Postpediatric pyeloplasty imaging should aim to identify those who require further intervention. Our data demonstrate that at-risk patients can be identified with a sentinel US and selectively determine who needs further MAG-3 investigation. This should increase compliance while decreasing costs, instrumentation, and radiation exposure.