Obstructive Hydronephrosis Research Articles

Spectrum of Disorders Diagnosed on 99mTc-MAG3 Radioisotope Renography: A Report of 260 Saudi Arabian Patients

Background: Diuretic renography using 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) is a relatively non-invasive technique and has been increasingly used as a reliable technique for the evaluation of kidney function in a wide range of kidney disorders. Methods: In this retrospective study, we retrieved the medical records of patients referred to the Radiology Department of Radiology, King Abdulaziz Specialist Hospital, Taif, Saudi Arabia, with suspected kidney disease and underwent 99mTc-MAG3 diuretic renography during January 2020 to November 2021. Results: The medical records of 260 patients were retrieved. Most of the patients had either suspected obstructive (n = 80; 30.7 %) or non-obstructive hydronephrosis (n = 60; 23.1 %). The left kidney was affected in more than half of the patients (n = 155; 59.6 %). In terms of split kidney functions, the right kidney had a median function of 50.9 (38.5–75.5); overall, 39 patients (69.6%) had good right kidney function. The left kidney had a median function of 49.4 (24.5–61.5); overall, 33 patients (58.9%) had good left kidney function. Conclusion: Radioisotope renography is useful for assessing kidney functions in real-life settings. The present study’s results indicate that radioisotope renography using 99mTc-MAG3 is helpful in the visual interpretation of kidney failure, obstructive uropathy and kidney stenosis.

69-Year-Old Man With Dysuria and Right Lower Abdominal Pain

69-Year-Old Man With Dysuria and Right Lower Abdominal Pain

Importance of the hounsfield unit value measured by computed tomography in the differentiation of hydronephrosis and pyonephrosis

BackgroundAcute or chronic obstruction of the urinary tract can be due to a lot of different causes. Patients with pyonephrosis usually complain of a triad of fever, loin pain and elevated white blood cell count in cases of acute obstruction; and they may also have hypotension in severe cases of the disease. These patients have to be treated with appropriate decompression, or they may develop septic shock. The urgency of the need for treatment greatly depends on the differentiation between hydronephrosis and pyonephrosis.There is a lack of reliable clinical prognosticators of pyonephrosis in patients with obstructive hydronephrosis. Hounsfield unit (HU) measurement is considered as an adequate predictor of pyonephrosis and may aid in the diagnosis and management of this disease that may be fatal.The use of HU values in differentiation between pyonephrosis from hydronephrosis depends on the fact that the pyonephrotic fluid contains infected material, urine, cellular particles and microorganisms, which when combined can increase the HU values on a computed tomography (CT) study.This study was done to assess the diagnostic value of the HU measured CT in differentiation between hydronephrosis and pyonephrosis.ResultsThirty-nine patients were included in this study. All patients had loin pain and were diagnosed with pelvicalyceal dilatation by ultrasonographic examination. They then underwent non-contrast CT examination.Using CT scan, the degree of PC dilatation was significantly higher among hydronephrosis group as hydronephrosis group had 63.1% severe dilatation of PCs versus 30.8% in pyonephrosis group with p value 0.0001.Pelvic wall thickness > 2 mm was reported in 10 (76.9%) patients of pyonephrosis group versus in three (7.9%) patients among hydronephrosis group with p value 0.0001.The mean Hounsfield units were significantly higher among pyonephrosis group compared to hydronephrosis group (16 ± 5.2 versus 1.7 ± 5.5) with p value 0.0001.Sensitivity analysis showed that Hounsfield units can significantly diagnose pyonephrosis using the cutoff point 6.2 units, with sensitivity 92.3%, specificity 93.3%, area under the curve (AUC) 96.9% and p value 0.0001.ConclusionsMeasuring HU in a NCECT scan of the kidney might be helpful for differentiating between hydronephrosis and pyonephrosis especially upon considering 6.2 HU as a cutoff point.

Diuretic Renal Scintigraphy Protocol Considerations.

Diuretic renal scintigraphy plays a critical diagnostic role by providing a physiologic means for differentiating between obstructive and nonobstructive hydronephrosis as well as assessing the function of the affected kidney. The exam accuracy is highly dependent upon and benefits from close attention to the protocol. This article reviews kidney anatomy and physiology, patient preparation, available radiopharmaceuticals, diuretic administration, acquisition, processing, quantification, and interpretation criteria.

When prolapse cannot be reduced: incarcerated procidentia due to pelvic mass

Our objective is to demonstrate a surgical approach to the treatment of incarcerated procidentia with obstructed ureters due to a pelvic mass. A 61-year-old woman presented with constipation, vaginal swelling, and difficulty voiding. On examination she had complete procidentia, which could not be reduced with gentle pressure. On imaging the prolapse appeared to contain a large pelvic mass measuring 11.5 cm in its greatest diameter, with features consistent with a mature teratoma. She was also noted to have bilateral ureteral obstruction and prominent hydronephrosis. After unsuccessful prolapse reduction under anesthesia, Bovie electrocautery was used to perform a posterior colpotomy. The obstructing mass was dissected away from the uterus and its connecting pedicle transected. The prolapse could then be reduced and a robotic hysterectomy performed. Pathology showed multiple pelvic masses including an 8-cm necrotic cystic nodule most consistent with uterine fibroids and a 4.5-cm mature cystic teratoma with associated seromucinous cystadenoma of the left ovary. Bilateral nephrostomy tubes were placed postoperatively. Incarcerated procidentia is an uncommon occurrence, which in rare cases may be due to a pelvic mass. Surgical management may be required with colpotomy for removal of the pelvic mass in order to reduce the prolapse and resolve the case.

Obstructive hydronephrosis with secondary urosepsis.

Obstructive uropathy is one of the leading causes of urosepsis. In patients with severe hydronephrosis, underlying sepsis and renal dysfunction should be treated with caution. The immediate drainage of hydronephrosis is crucial for infectious source removal and is hence related to the patient's prognosis.

Evaluating TIMP-2 and IGFBP-7 as a predictive tool for kidney injury in ureteropelvic junction obstruction.

ABSTRACTA major challenge in the management of ureteropelvic junction obstruction (UPJO) is the selection of patients who would benefit from surgical treatment. Tissue inhibitor metalloproteinase-2 (TIMP-2) and insulin-like growth factor-binding protein 7 (IGFBP7) indicate renal cell stress and are associated with cell cycle arrest. The [TIMP-2] [IGFBP7] ratio (Nephrocheck®) has been recently applied in patients in intensive care units patients to predict the development of acute kidney injury. In this study, we evaluated the performance of these biomarkers performance to distinguishing obstructive hydronephrosis (HN) from non-obstructive HN.Materials and Methods:Consecutive patients with UPJO were enrolled in this study. Urinary [TIMP-2] [IGFBP7] and clinical characteristics (hydronephrosis grade, differential renal function, and drainage half-time) were measured in the following groups: 26 children with obstructive HN at initial diagnosis (group 1A) and after six months of dismembered pyeloplasty (group 1B); 22 children with non-obstructive HN (group 2), and 26 children without any urinary tract condition, as the control group (group 3).Results:Comparing the initial samples, [TIMP-2] [IGFBP7] had higher levels in the HN groups and lower levels in the control group; however, no difference was observed between the HN groups (obstructive vs. non-obstructive). After six months of follow-up, patients who underwent dismembered pyeloplasty showed stability in the urinary concentration of [TIMP-2] [IGFBP7]. All patients with [TIMP-2] [IGFBP7] higher than 1.0 (ng/mL)2/1000 had diffuse cortical atrophy on ultrasonography.Conclusions:We showed that urinary levels of urinary [TIMP-2] [IGFBP7] are higher in children with HN than controls. Nephrocheck® is not reliable in predicting the need for surgical intervention for pediatric patients with UPJO.

Correlation of resistive index of main renal artery and inter-lobar artery with degree of hydronephrosis.

Objective: To study the correlation of resistive index of main renal artery and inter-lobar artery with degree of hydronephrosis. For the purpose of this study data collection was carried through different research works conducted previously regarding hydronephrosis and its effects on the resistivity index of renal arteries. Study Design: Systemic Review. Setting: Radiology Research Section, University of Lahore. Period: September 2018 to May 2020. Material & Methods: Research was conducted with the help of keywords. One hundred and three articles were found at initial stage. A table was designed for data collection purpose including the information such as author of article, year of research, type of hydronephrosis, number of patients, and the resistive index of renal arteries. The data included both male and female patients of any age suffering from hydronephrosis of any origin and no area or time limitation was applied. Results: Pooling results of this systematic review depicts that the researchers conducted various researches addressing the cause of hydronephrosis, the effect of type of hydronephrosis on the resistive index, difference between resistivity index of obstructive and non-obstructive hydronephrosis, level of obstruction and its effect on RI of the renal artery, factors that influence RI other than renal in origin but not a single research conducted on human subject represents the correlation of different grades or degrees of hydronephrosis with either main renal artery or inter-lobar arteries. Out of 17 articles, 8 (47%) articles discuss the resistive index for both obstructive and non-obstructive hydronephrosis while remaining 9 (53%) articles discuss only the mean resistive index for the obstructed kidney. Conclusion: Although renal resistive index is the parameter which is influenced by a variety of other factors such as age of patient, plasma renin level, and the simultaneous presence of certain diseases like hypertension, cardiac diseases, diabetes mellitus, and renal disorders. The presence of any of these factors may rise the RI values even if there is no renal obstruction. Yet different research mainly shows that the values of RI are high i.e. >0.70 in case of obstructed kidney while generally the values of RI are <0.70 in case of none obstructed kidney.

Severe Hydronephrosis Secondary to Ovarian Serous Carcinoma

This case study examines a patient with severe hydronephrosis caused by ureteral obstruction, secondary to ovarian serous carcinoma. Gynecologic malignancies, especially advanced ovarian carcinoma, are common extrinsic causes of obstructive hydronephrosis. Sonography is a valuable modality to visualize the kidneys, diagnose hydronephrosis, and determine the grade of hydronephrosis. The treatment of hydronephrosis aims to remove the build-up of urine, prevent permanent kidney damage, and treat the underlying cause. Prolonged or severe cases of hydronephrosis can lead to acute kidney injury.

Moderate Hydronephrosis among Acute Ureteral Calculus on Ultrasonographic Imaging in a Tertiary Care Center in Nepal: A Descriptive Cross-sectional Study.

Ureteric calculi are lying at any point of ureter from the pelvic ureteric junction to the vesicoureteral junction. If left untreated, ureteropelvic junction obstruction can lead to hydronephrosis. With the improved availability of computed tomography and ultrasound scanning, hydronephrosis is being diagnosed more frequently. The main aim of this study is to find out the prevalence of moderate Hydronephrosis among ureteral calculus on ultrasonography imaging in a tertiary care center of Nepal. A descriptive cross-sectional study was conducted among 110 acute ureteral calculus cases at Radiodiagnosis and Imaging Department of Chitwan Medical College and Teaching Hospital, Bharatpur from 15th August 2020 to 15th May 2021. The ethical approval was taken from the Institutional Review Committee of same institution. Convenient sampling technique was used to select the participant. The collected data was entered in excel 16 and analysed in Statistical Package for Social Sciences. Point estimate at 95% Confidence Interval was done and frequency and percentage were calculated. Out of the 110 cases of acute ureteral calculus, 31 (28.2%) (19.79-36.60 at 95% Confidence Interval) has moderate hydronephrosis in the ultrasonographic imaging. The mean age of participants was 31.61±8.51 years and male to female ratio was 1.97:1. Vesicoureteric junction was the most common site for ureteric calculus 39 (35.5%). The ultrasound is an easy method to be applied, and a fast one to help and diagnose obstructive hydronephrosis. The main causes of hydronephrosis are kidney stones, followed by ureteral stones, with a moderate degree of hydronephrosis.

Role of nuclear medicine SPECTCT methods in the diagnosis of Urinary Tract Urothelial Cell Cancer

Nuclear medicine methods, with subsequent hybrid SPECT-CT images, are highly sensitive and specific visual methods that establish the functional status of the target organs, diagnose and stage pathological secondary lesions with increased mineral activity in bone and joint structures and determine the exact localization, anatomical structure and the corresponding morphological characteristics of the tumors localized in the lower and upper urinary tract. Urothelial carcinomas develop in the process of malignant transformation of cells of the transitional epithelium. Depending on their location, urothelial tumors are divided into those that develop in the lower urinary tract (bladder, urethra) and in the upper urinary tract (ureters and collecting system of both kidneys). Whole-body bone scintigraphy and dynamic nephroscintigraphy with subsequent targeted SPECT-CT studies are of great clinical importance in patients with these oncological localizations for the accurate diagnosis and staging of bone secondary lesions, for visualization of obstructive hydronephrosis and relative renal function, especially in high-risk patients Key words: urothelial carcinomas, SPECT-CT, dynamic nephroscintigraphy, bone scintigraphy

Quantitative evaluation of upper urinary tract pump function in pigs with acute unilateral lower ureteral obstruction by 640-slice dynamic volume CT

BackgroundIt is a challenging problem to differentiate obstructive hydronephrosis from noninvasive evaluation of renal pelvis and ureteral motility in patients. The purpose of this study was to explore the value of 640-slice dynamic volume CT (DVCT) in the quantitative measurement of upper urinary tract (UUT) pump function after acute unilateral lower ureteral obstruction in pigs.MethodsIn this study, a perfusion pig model was constructed by constant pressure perfusion testing of the renal pelvis and left nephrostomy. The perfusion and pressure measuring devices were connected to create a state of no obstruction and acute obstruction of the lower part of the left ureter. After successful modelling, continuous dynamic volume scanning of the bilateral renal excretion phase was performed with 640-slice DVCT, and pump functions of the renal pelvis and part of the upper ureter were calculated and analysed. No obstruction or acute obstruction of the lower part of the left ureter was observed. Pump functions of the renal pelvis and part of the upper ureter were determined.ResultsThe results showed that after LUUT fistulostomy, the time difference between the average UUT volume and positive volume value increased gradually, and the calculated flow velocity decreased, which was significantly different from that of the RUUT. The volume difference of the LUUT increased significantly in mild obstruction. In the bilateral control, the volume change rate of the LUUT increased with mild obstruction and decreased with severe obstruction, and there was a significant difference between the left and right sides.ConclusionThe continuous dynamic volume scan and measurement of 640-slice DVCT can obtain five pump function datasets of UUT in pigs with acute lower ureteral obstruction.

A Rare Case of Abdominal Aortic Aneurysm with Ureteral Compression

Abstract Introduction: In this report, we present a rare case of aortic aneurysm with associated left ureter obstruction and consequent hydronephrosis. Case presentation: A 62-year-old man was admitted for epigastric and periumbilical pain, extended in the spine, and anuria. As for associated diseases, he presented arterial hypertension stage II/III, chronic ischemic cardiomyopathy, acidosis, hyperpotassemia, spondylosis with radiculopathy, acute renal failure, renal lithiasis, and eating difficulties. After performing a CT scan, the patient was diagnosed with giant abdominal infrarenal aortic aneurysm with ureter compression, and retroperitoneal rupture with common and internal iliac arteries occlusion. We performed a xifo-pubian laparotomy with endoaneurysmorrhaphy and aortoiliac bilateral bypass using silver Dacron vascular prosthesis (16 × 8 mm in diameter). Douglas drainage was necessary, ending with laparoraphy. The patient presented a favorable postoperative evolution. Conclusion: Open surgery remains the gold standard method of treatment for large aortic aneurysms, given the inability of endovascular procedures to solve problems caused by compression.

Urosepsis and hydronephrosis secondary to vaginal vault prolapse: A case report

Pelvic organ prolapse (POP) is a common condition affecting older women. POP can cause hydronephrosis in some patients. Although rare, especially in the subset of patients with vaginal vault prolapse, unrecognized obstructive hydronephrosis can result in renal impairment and urosepsis. We present a case of a 69-year-old female with obstructive urosepsis on a background of vaginal vault prolapse. The case highlights the importance of early recognition and intervention of obstructive urosepsis in patients with severe POP disease. Level of evidence: Not applicable for this multicentre audit.

Machine learning-assisted decision-support models to better predict patients with calculous pyonephrosis

BackgroundTo develop a machine learning (ML)-assisted model capable of accurately identifying patients with calculous pyonephrosis before making treatment decisions by integrating multiple clinical characteristics.MethodsWe retrospectively collected data from patients with obstructed hydronephrosis who underwent retrograde ureteral stent insertion, percutaneous nephrostomy (PCN), or percutaneous nephrolithotomy (PCNL). The study cohort was divided into training and testing datasets in a 70:30 ratio for further analysis. We developed 5 ML-assisted models from 22 clinical features using logistic regression (LR), LR optimized by least absolute shrinkage and selection operator (Lasso) regularization (Lasso-LR), support vector machine (SVM), extreme gradient boosting (XGBoost), and random forest (RF). The area under the curve (AUC) was applied to determine the model with the highest discrimination. Decision curve analysis (DCA) was used to investigate the clinical net benefit associated with using the predictive models.ResultsA total of 322 patients were included, with 225 patients in the training dataset, and 97 patients in the testing dataset. The XGBoost model showed good discrimination with the AUC, accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 0.981, 0.991, 0.962, 1.000, 1.000, and 0.989, respectively, followed by SVM [AUC =0.985, 95% confidence interval (CI): 0.970–1.000], Lasso-LR (AUC =0.977, 95% CI: 0.958–0.996), LR (AUC =0.936, 95% CI: 0.905–0.968), and RF (AUC =0.920, 95% CI: 0.870–0.970). Validation of the model showed that SVM yielded the highest AUC (0.977, 95% CI: 0.952–1.000), followed by Lasso-LR (AUC =0.959, 95% CI: 0.921–0.997), XGBoost (AUC =0.958, 95% CI: 0.902–1.000), LR (AUC =0.932, 95% CI: 0.878–0.987), and RF (AUC =0.868, 95% CI: 0.779–0.958) in the testing dataset.ConclusionsOur ML-based models had good discrimination in predicting patients with obstructed hydronephrosis at high risk of harboring pyonephrosis, and the use of these models may be greatly beneficial to urologists in treatment planning, patient selection, and decision-making.

Evaluation of the Patients with Antenatal Hydronephrosis Diagnosed Ureteropelvic Junction Obstruction with the Hydronephrosis Severity Score

Objective: Ureteropelvic junction obstruction is the main cause of obstructive antenatal hydronephrosis. Although surgery is the traditional treatment modality, there is still no consensus on surgical indications. We aimed to analyse the patients referred as antenatal hydronephrosis and diagnosed with ureteropelvic junction obstruction with Hydronehprosis Severity Score that has been developed by Babu at al. Method: The patients who were admitted with antenatal hydronephrosis in 2013-2018 and diagnosed as ureteropelvic junction obstruction and followed up in our clinic for at least one year were evaluated. The cases with unilateral hydronephrosis were included. Those with vesicoureteral reflux, horseshoe kidney, hydroureter, ureterovesical junction obstruction were excluded. Renal ultrasonography and nuclear scintigraphy results were re-evaluated. They were grouped as mild (0-4), moderate (5-8) and severe (9-12) based on scoring of three parameters; differantial renal function, drainage curve pattern and US grade. Clinical outcomes were also classified in three groups; resolution (grade 1-no hydronephrosis), persistance (grade 2-3 hydronephrosis) and surgical intervention. The relation between the scores and clinical outcomes were analysed. Results: A total of 57 patients were evaluated. 2 with horseshoe kidney, 4 with vesicoureteralreflux, 7 with bilateral hydronephrosis, 4 with ureteric outlet obstruction, 12 with incomplete records were excluded. Finally, 28 patients were included. Hydronephrosis was resolved in 4 (14.2%), persisted in 5 (17.8%) and surgical intervention was required in 19 (67.8%) patients. 1/5 patients with mild, 15/20 patients with moderate and 3/3 patients with severe HSS underwent surgery. 77.2% of the patients with a total score of ≥6 initially required surgical intervention at their follow-up. Conclusion: HSS may provide a significant predictive value for surgical intervention for the patients classified as “mild” or “severe” at the initial evaluation. In the “moderate” group, the risk increases in the patients with HSS≥6. Existing data should be evaluated with larger case series.

Screening of renal anomalies in first-degree relatives of children diagnosed with non-syndromic congenital anomalies of kidney and urinary tract.

Non-syndromic congenital anomalies of kidney and urinary tract (CAKUT) are usually sporadic in nature but familial clustering of cases have been observed suggesting a genetic predisposition to this condition. We aimed to determine the frequency and pattern of renal anomalies in first-degree relatives of children with non-syndromic CAKUT. We screened all the first-degree relatives of children with CAKUT. A total of 149 first-degree relatives, belonging to 62 families were screened with ultrasonography. A renal anomaly was detected in 9 out of the 62 families. Two of these nine families had identical anomalies (child and a parent) indicating single-gene disorders with possible autosomal dominant inheritance, while the rest of families had a non-identical anomaly. The anomalies detected in the first-degree relatives were renal hypodysplasia (n = 2), multicystic dysplastic kidney (n = 3), pelviureteric junction obstruction (n = 2) and mild hydronephrosis (n = 2). The incidence of a sonographically detected anatomic renal anomaly in first-degree relatives of children with CAKUT was found to be 6.0%. Familial cystic kidney disease was found in two out of the 4 families with cystic kidney disease. Significant renal anomalies were identified in first-degree relatives of children with non-syndromic CAKUT and hence, attempts must be made to screen the family members of children with non-syndromic CAKUT.

Pyonephrosis drained by double-J catheter.

An infectious disease with obstructive hydronephrosis, pyonephrosis causes suppurative destruction of the renal parenchyma. In such cases, retrograde ureteric stenting is considered a good choice for the drainage of pyonephrosis, as an alternative to percutaneous nephrostomy and nephrectomy. The complication rate is minimal in retrograde ureteric stenting compared with about 4% in percutaneous nephrostomy.

Use of double-J ureteric stents post-laparoscopic pyeloplasty to treat ureteropelvic junction obstruction in hydronephrosis for pediatric patients: a single-center experience.

ObjectivesWe aimed to investigate the safety concerns associated with placing double-J ureteric stents post-laparoscopic pyeloplasty surgery for congenital ureteropelvic junction obstruction (UPJO) and hydronephrosis.MethodsA total of 1349 patients with postoperative double-J stent placement at our center were included. Clinical variables for enrolled patients were collected by two independent authors. We compared clinical variables and the efficacy of stenting post-laparoscopic pyeloplasty.ResultsThe mean age of the patients was 4.23 ± 2.39 years. A total of 58.49% of patients were diagnosed with left UPJO with hydronephrosis and 33.95% were diagnosed with right UPJO. Furthermore, 7.56% of patients had bilateral UPJO. In all cases, 96.96% of indwelling double-J stents were successfully removed 4 weeks post-surgery. A total of 3.04% of the patients still required further management, including stent migration to the renal pelvis (0.37%), stent migration to the bladder (0.30%), prolapse of the stent through the ureter (0.15%), blockage of stents (1.85%), and fouling of stents (0.37%).ConclusionsDouble-J ureteric stents used after laparoscopic pyeloplasty for treating UPJO in hydronephrosis for pediatric patients is a safe, feasible, and beneficial method, which can be recommended for routine procedures. However, caution should be practiced for follow-up and removal using this method.

Urinary biomarkers in pelvic-ureteric junction obstruction: a systematic review

Antenatal hydronephrosis is a common finding detected on prenatal ultrasound. Although hydronephrosis will spontaneously resolve in the majority of newborns, there is a significant amount of cases that will worsen with the risk of a progressive and permanent loss of renal function. There is an increasing concern among experts that the current criteria for evaluation of clinically significant obstructions are limited. Our aim is to provide a systematic review of the available literature on biomarkers of renal injury, potential targets for diagnosis and prognosis of children with hydronephrosis. The main search was conducted in the electronic databases from inception through March 2019 using various combinations of the keywords: pelvic-ureteric [All Fields] AND junction [All Fields] AND obstruction [All Fields] AND “biomarkers” [MeSH Terms] OR “biomarkers” [All Fields] OR “biomarker” [All Fields]. To broaden the research, additional articles were identified through hand-searching review of the references reported in each study previously selected. Histopathological studies, studies with no control group or with participants suffering from concomitant urological diseases and articles published in language other than English were excluded. Data on study design, sample size, average patient age, hydronephrosis definition used, surgical indication, duration and pattern of follow-up, details on biomarker studied, diagnostic test characteristics, area under the curve (AUC) on receiver operating characteristic (ROC) analysis with the best cut-off (BCO) values, sensitivity, specificity and outcomes were all collected. 38 articles analysing 41 biomarkers were selected. The most frequent proteins investigated were neutrophil gelatinase-associated lipocalin (NGAL) (n=9; 23.7%), monocyte chemotactic peptide-1 (MCP1) (n=8; 21.1%), transforming growth factor β1 (TGFβ1) (n=7; 18.4%), epidermal growth factor (EGF) (n=6; 15.8%) and kidney injury molecule 1 (KIM 1) (n=6; 15.8%). Twenty-seven (71.1%) studies evaluated the effect of pyeloplasty on voided urine biomarker concentrations, comparing their values before and after surgery. Twelve (31.6%) studies investigated the correlation between preoperative biomarker concentration and the anterior posterior renal pelvis diameter (DAP) while 20 (52.6%) studies investigated the correlation between preoperative biomarker concentration with the split renal function (SRF) measured on nuclear medicine assessments. ROC curves were used to investigate the performance of urinary biomarkers in the total patient data set in 27 (71.1%) studies. Some biomarkers offer promising results. However, a critic analysis of the published studies demonstrates bias and lack of consistency suggesting that larger multicentre and carefully designed prospective studies are still needed to evaluate the clinical usefulness of urinary biomarkers in the diagnosis and follow-up of children with congenital obstructive hydronephrosis.