Hybrid Retroperitoneoscopic Pyeloplasty for Congenital Ureteropelvic Junction Obstruction in Infants Weighing Less than 10 kg.

Introduction: Success rate of laparoscopic pyeloplasty for ureteropelvic junction obstruction (UPJO) in children is comparable with open pyeloplasty. Prolonged ileus and injury to adjacent viscera more often occurred in transperitoneal approach; however, longer operation time is noted in retroperitoneal approach. Purpose: This study presented a hybrid retroperitoneoscopic pyeloplasty (HRP), for congenital UPJO in infants weighing <10 kg. Materials and Methods: From February 2017 to June 2020, 10 HRP procedures were performed in 9 patients by 1 surgeon. Retroperitoneal dissection of the renal pelvis and the upper third ureter was first performed, followed by extracorporeal suturing for pyeloureterostomy. Results: Mean operative age and body weight were 4.23 ± 3.69 months and 6.18 ± 1.57 kg. Operative, CO2 inflation, and extracorporeal suture time were 147.9 ± 39.5, 40.6 ± 11.2, and 62.9 ± 26.1 minutes, respectively. Surgical outcome was confirmed by renal ultrasound and diuretic renogram. Postoperative follow-up duration was 15.2 ± 7.7 months. Three patients had postoperative febrile urinary tract infection and recovered after antibiotic treatment. Conclusion: In infants or smaller children with UPJO, the HRP procedure may be considered as an effective and minimally invasive alternative with shorter learning curve for inexperienced surgeons.

Posterior Urethral Valve and Prenataly Resolved Multicystic Dysplastic Kidney.

Multicystic dysplastic kidney is a rare congenital anomaly of the kidney and urinary tract. The association with the posterior urethral valve is also very rare. Here we present a patient with both entities and prenatal resolution of the cysts.A 10-week old baby was referred for nephrourological work up due to prenatal diagnosis of the left multicystic kidney. He had serial US scans during the pregnancy. Immediately before delivery the cysts were not seen (prenatal resolution). There were no extrarenal anomalies. The first postnatal ultrasound scan revealed normal sized right kidney without dilatation of the pelvicalyceal system. The bladder had normal thickness of the wall. Technetium-99m dimercaptosuccinic acid scan showed no activity on the left side, and the right kidney appeared normal. At two months of age, a poor urinary steam was observed and additional urologic work up was indicated on clinical suspicion of PUV. Voiding urethrocystography revealed posterior urethral valve and the baby underwent cytoscopic valve resection.Conclusion: We present a rare association of two congenital anomalies of the kidney and urinary tract with prenatal involution of the multicystic dysplastic kidney that is extremely rare event as seen in our case. Presence of posterior urethral valve must be suspected in a male baby with a poor urinary stream even when his ultrasound scan of urinary system appears normal.

Prenatal diagnosis and outcome of unilateral multicystic kidney.

We reviewed the records of 144 patients. The mean gestational age at first US diagnosis was 27.5 ± 4.3 weeks. An anomaly of the contralateral kidney was detected in 25% of cases. An extrarenal anomaly was detected in 13.8%. Karyotype analysis was performed in 16.6% of cases and revealed trisomy 18 in 2 cases with extrarenal defects. Karyotype analysis was normal in all the patients who had isolated multicystic dysplastic kidney (MCDK). The diagnostic accuracy of prenatal ultrasound was 92.2%. Contralateral kidney anomaly was detected 33.9% of patients, and half of these were vesicoureteral reflux. Antihypertensive therapy was required in 2.6% of cases. Nephrectomy was performed in 8%, and partial or total involution of MCDK was achieved in 33.9% of patients. MCDK can be accurately diagnosed by prenatal sonography, and prognosis depends on extrarenal and contralateral renal abnormalities. In isolated cases, require of surgery is rare, and serial follow-up is suggested to determine involution.Impact statementWhat is already known on this subject? Multicystic dysplastic kidney (MCDK) is one of the most renal anomalies and is associated with numerous renal and extrarenal abnormalities. It can lead to severe consequences in the neonatal period.What do the results of this study add? The accuracy of prenatal ultrasonography is excellent for detecting MCDK. In isolated unilateral cases, chromosomal aberrations are low, and the majority of them involute spontaneously. A periodic follow-up of the contralateral kidney is mandatory due to an increased risk of an anomaly. Genital anomaly risk is increased in males.What are the implications of these findings for clinical practice and/or further research? Detailed evaluation and follow-up of the contralateral kidney are crucial for counselling in isolated cases. Karyotype analysis in isolated unilateral MCDK is debateable. Postnatal prognosis is encountering, and the majority of patients have no requirement of surgery.

Multicystic Dysplastic Kidney With Mass Effect in a Neonate Treated With Nephrectomy: Case Report.

Multicystic Dysplastic Kidney is a developmental disease that results in a lobulated kidney of noncommunicating cysts and abnormal parenchymal tissue. Dysplastic kidneys are usually benign and often involute over time with conservative management. The second most common cause of palpable abdominal mass in a neonate, Multicystic Dysplastic Kidney can cause respiratory distress secondary to extrinsic compression. However, such cases are sparse. Here we present the case of an otherwise healthy term newborn with an exceptionally large MCDK requiring CPAP support and intubation. His respiratory distress improved immediately after nephrectomy. Communication about cases like this will inform management of future comparable cases.

Robot-assisted laparoscopic pyeloplasty (RALP) in children with complex pelvi-ureteric junction obstruction (PUJO): results of a multicenter European report.

PURPOSE: This study aimed to report a multi-institutional retrospective case series of outcomes after robot-assisted laparoscopic pyeloplasty (RALP) in pediatric patients with complex pelvi-ureteric junction obstruction (PUJO). METHODS: All patients undergoing complex RALP over the last 5 years were included. RALP was defined complex in the following cases of PUJO: anatomic variations including ectopic, malrotated, horseshoe, or duplex kidney and recurrent PUJO after failed open pyeloplasty. RESULTS: Forty-eight patients underwent complex RALP in four European centers in the study period and included 18 girls and 30 boys with a median age of 8 years (range 5-12). The PUJO was associated with anatomic variations in 35/48 (72.9%), whereas a recurrent PUJO was present in 13/48 (27.1%). A dismembered Anderson-Hynes pyeloplasty was performed in all patients. The median operative time including docking was 178.5 min (range 117-255) and the median anastomotic time was 64.8 min (range 50-76). All patients were discharged on 2nd postoperative day (POD). The median follow-up was 18.2 months (range 14-43). The overall success rate was 95.8% (46/48). Early postoperative complications (< 30th POD) included urinary tract infections (UTIs) and stent-related irritative symptoms in 4/48 (8.3%) [II Clavien], whereas late complications (> 30th POD) included recurrence of PUJO in 2/48 (4.2%), who needed re-operation [IIIb Clavien]. CONCLUSIONS: RALP was safe, feasible, and with good mid-term outcome in complex PUJO. An accurate pre-operative planning, a standardized technique, and an experienced surgical robotic team represented key points to manage successfully such complex cases.

A comparison between short- and long-term D-J stent in Anderson-Hynes pyeloplasty for pelvi-ureteric junction obstruction.

PURPOSE: A double-J (D-J) stent is usually kept in situ during Anderson-Hynes (A-H) pyeloplasty for pelvi-ureteric junction (PUJ) obstruction. The aim of the study is to determine whether early removal of D-J stent is better than long-term stenting. METHODS: In this prospective comparative study, conducted from January 2018 to April 2019 in Chittagong Medical College Hospital, patients with PUJ obstruction, age less than 12 years, were divided into group A (long-term stenting) and group B (short-term stenting) by simple randomization. Main outcome variables were urinary tract infection (UTI), stent colonization, encrustation, renal cortical thickness, differential renal function (DRF), glomerular filtration rate (GFR), and flow rate in DTPA renogram. RESULTS: There were 31 patients in each group. Median age was 5 years (IQR: 2.3 to 7 years) and male to female ratio was 2.1:1. Frequency of post-operative UTI and stent colonization were significantly higher in group A than group B (p < 0.001). All the patients of both groups had similar improvement in renal cortical thickness, DRF, GFR, and flow rate. The study was potentially limited by its small sample size and high median age (5 years). CONCLUSION: Early removal of D-J stent had lower incidence of UTI, stent colonization, encrustation, and stent migration.

Our experience with laparoscopic Anderson-Hynes ureteropyeloplasty. / Ureteropieloplastia Anderson-Hynes laparoscópica en niños. Nuestra experiencia.

OBJECTIVE: To analyze whether the application of laparoscopic surgery in the treatment of pyeloureteral junction obstruction (PUJO) has been beneficial for pediatric patients. MATERIALS AND METHODS: Medical records of all patients undergoing PUJO surgery from January 1997 to December 2017 were retrospectively reviewed. Patients with <6-month follow-up and patients undergoing video-assisted surgery were excluded. Open surgery was compared with laparoscopic surgery. The following data were collected: surgical approach, need for and type of urinary diversion, operating time, mean hospital stay, complications, and restenosis rate. Ultrasound and diuretic renogram parameters were also retrieved. RESULTS: 328 Anderson-Hynes pyeloplasties were analyzed, 142 of which had been performed laparoscopically. Overall success rate was 96.6%, and complication rate was 11.9%. No significant differences were noted between open and laparoscopic surgery. In 97.5% of surgeries, urine was diverted using an external nephroureteral catheter, a double J stent, or a Salle stent, with significant differences between open and laparoscopic surgery. Mean operating time was significantly longer in laparoscopic surgery. Mean hospital stay was significantly shorter in the laparoscopic surgery group. CONCLUSION: Surgical approach does not play a role in PUJO surgery success. Therefore, in our view, laparoscopic surgery should be the technique of choice in pediatric patients.

OBJETIVO: Analizar si la aplicación de la cirugía laparoscópica en el tratamiento de la estenosis pieloureteral (EPU) han sido beneficiosos para el paciente pediátrico. MATERIAL Y METODO: Hemos revisado de forma retrospectiva las historias clínicas de todos aquellos pacientes intervenidos de EPU desde enero 1997 hasta diciembre 2017. Se excluyeron las que tuvieron seguimiento menor a 6 meses, y las cirugías videoasistidas. Se han comparado la cirugía abierta con la cirugía laparoscópica. Se han recogido los siguientes datos: abordaje quirúrgico, necesidad y tipo de derivación urinaria, tiempo quirúrgico, estancia media, complicaciones, tasa de reestenosis. Los parámetros ecográficos y del renograma diurético también han sido recogidos. RESULTADOS: Se han analizado 328 pieloplastias, 142 se realizaron laparoscópicamente. La tasa de éxito global ha sido del 96,6%, existiendo un 11,9% de complicaciones; sin existir diferencias significativas entre la cirugía abierta y la laparoscópica. En el 97,5% de las cirugías, la orina se derivó mediante catéter nefroureteral externo, catéter doble J o catéter tipo Salle; existiendo diferencias entre cirugía abierta y laparoscópica. El tiempo quirúrgico medio fue significativamente superior en la cirugía laparoscópica. La estancia media fue menor en el grupo de cirugía laparoscópica de forma significativa. CONCLUSION: La vía de abordaje no es un factor que influya en el éxito de la cirugía de la EPU, por ello pensamos que la cirugía laparoscópica es la técnica de elección en pacientes pediátricos.

Multicystic dysplastic kidney - treat each case on its merits.

OBJECTIVES: To assess outcomes of unilateral multicystic dysplastic kidney (MCDK) managed at an Australasian centre over a 15 year period. To assess if MCDK involution could be predicted based on change noted between first two postnatal ultrasound scans 6 months apart. SUBJECTS AND METHODS: A retrospective study was performed. RESULTS: One-hundred-and-six cases of unilateral MCDK were studied. Eighty-four of these presented antenatally. Twenty-two MCDK cases presented postnatally. Urological anomalies associated with MCDK included vesicoureteric reflux (VUR), ureterocele and contralateral pelviureteric junction obstruction (PUJO). Children undergoing surgical intervention for these anomalies were offered concurrent MCDK nephrectomy. Morbidity associated with MCDK under surveillance included febrile culture-positive urinary tract infection in 20 cases (20.7%), hypertension in four (3.7%) and Wilms' tumor in one (0.9%). Thirty-six cases (34%) underwent complete involution, 32 (30.2%) were in the process of involuting and 38 cases (35.8%) underwent nephrectomy because of failure of involution or associated morbidity. If the MCDK reduced in cranio-caudal interpolar length by 20% or more between the first postnatal USS and the next one 6 months later, then it was very likely to involute spontaneously. If the MCDK did not reduce in cranio-caudal interpolar length by 20% between the first postnatal scan and the next one 6 months later, then it was highly likely to fail to involute, and in our study, correlated with the outcome of nephrectomy. CONCLUSION: Although MCDK is a benign condition, it should be carefully investigated and followed-up, as involution may not occur in over a third. In some cases, morbidity may occur. Each case of MCDK should be managed on its own merits. LEVEL OF EVIDENCE: Level II - Prognosis study, Retrospective.

[Pelviureteric junction obstruction and crossing vessels: pro "vascular hitch"]. / Subpelvine Stenose & kreuzende Gefäße ­ Pro "vascular hitch".

The vascular hitch procedure for pelviureteric junction obstruction caused by crossing lower-pole vessels is a controversial treatment option. Since this minimally-invasive technique has been introduced in patients with aberrant lower-pole vessels, multiple publications have reported successful short, intermediate and long-term outcomes. Success rates of > 90 % are similar to those of Anderson-Hynes pyeloplasty. In general, an associated intrinsic stenosis seems to be rare. Histological evidence of muscular hypertrophy may simply indicate a compensatory mechanism and may be reversible to a certain degree. To differentiate between those patients who are eligible for a vascular hitch procedure and those who should receive an initial Anderson-Hynes pyeloplasty, an intraoperative diuretic test should be performed (volume bolus plus intravenous administration of furosemide). An associated intrinsic stenosis seems to be unlikely in a funnel-like and otherwise normal-looking pelviureteric junction, decreasing hydronephrosis after mobilisation of renal pelvis and crossing vessels and effective peristalsis of the renal pelvis after intraoperative diuretic testing. The vascular hitch technique is less demanding than laparoscopic Anderson-Hynes pyeloplasty and less time-consuming with regard to the duration of the surgical procedure and anaesthesia. Further advantages are: no risk of urinary leakage or anastomotic stricture and no need for intra-luminal stenting. Therefore, in a selected group of patients with solely extrinsic pelviureteric junction obstruction, the vascular hitch procedure is a valuable alternative to classic Anderson-Hynes pyeloplasty with seemingly long-term efficiency.

Laparoscopic transposition of lower pole crossing vessels in children with extrinsic pelvi-ureteric junction obstruction: a worthy alternative to dismembered pyeloplasty.

Pelviureteric junction obstruction (PUJO) due to intrinsic or extrinsic causes is a common problem in childhood. Extrinsic compression by a lower pole-crossing blood vessel can present symptomatically in older children. In these cases, laparoscopies Vascular Hitch can represent a valid alternative to pyeloplasty dismembered. We analyzed the data of 4 children affected by extrinsic PUJO treated at our institution with the laparoscopic Vascular Hitch procedure modified by Chapman. Surgical indications included presence of clinical symptoms, worsening of intermittent hydronephrosis, signs of obstruction on the MAG-3 scan, clear or suspected images of polar crossing vessels on CT scan or Uro-MRI. All procedures were completed laparoscopically. No complications occurred. Mean follow-up was 13 months with resolution of symptoms and PUJ obstruction and significant improvement of hydronephrosis in all cases. When blood vessels crossing lower pole represent the pure mechanical cause of UPJ obstruction the laparoscopic Vascular Hitch procedure represents an excellent alternative to dismembered pyeloplasty. It is less technically demanding then pyeloplasty and is associated with a lower complication rate. The main challenge is to intraoperatively ascertain the absence of associated intrinsic stenosis.

Trends in surgical management of multicystic dysplastic kidney at USA children's hospitals.

INTRODUCTION AND OBJECTIVE: Multicystic dysplastic kidney (MCDK) is a congenital renal cystic disease often incidentally diagnosed in children. Historically, children with MCDK underwent early nephrectomy because of concerns for the development of hypertension or malignancy. Over the last decade, management recommendations have not supported routine early surgical removal of MCDK. The study authors sought to determine the current trends in the use of nephrectomy for MCDK in US children's hospitals because national practice patterns have not been investigated. METHODS: A population-based retrospective cohort study using the Pediatric Health Information System (PHIS) was conducted. The study population was comprised of patients aged 0-18 years with a diagnosis of MCDK (International Classification of Diseases-9th revision, code 753.19) admitted to the inpatient department of the study hospital between January 2006 and September 2015. Patients with additional renal anomalies including polycystic kidney, medullary cystic kidney, and medullary sponge kidney were excluded, as were patients treated in a hospital that did not contribute data to the PHIS continuously throughout the study period. Trends in the annual proportion of nephrectomies performed were analyzed among admissions in the study population, along with patient clinical and demographic information. RESULTS: A total of 3792 MCDK admissions, in 34 hospitals, were included in the study. Overall, 569 nephrectomies were performed during the study period. The proportion of nephrectomy decreased annually by 9.2% on average, from 22.1% in 2006 to 7.3% in the first 3 quarters of 2015. No significant trends were observed in the annual number of overall MCDK admissions or patient age at procedure among patients who had a nephrectomy. Among nephrectomies, 84.2% were open and 15.8% were minimally invasive procedures (laparoscopic non-robotic, 10% and robotic, 5.8%). The proportion of minimally invasive nephrectomies increased annually by 13.7%, from 8% in 2006 to 29% in 2015. DISCUSSION: Trends in the use of nephrectomy for MCDK at a national level have not been previously reported. This study is limited by the use of inpatient discharge data, which did not allow estimating the true rate of nephrectomy in patients born with MCDK. CONCLUSIONS: During the study period, there has been a decrease in the use of nephrectomy for MCDK in pediatric hospitals, along with a concurrent increase in utilization of minimally invasive techniques to perform nephrectomies. These results suggest that in general, urologists at freestanding children's hospitals are heeding recommendations for observation and against routine early surgical removal of these kidneys; although trends in the use of nephrectomy varied between hospitals, there is room for continued improvement in following these recommendations.

Rare case with plethora of upper urinary tract anomalies associated with pelviureteric junction obstruction: a surgical challenge managed with robot assistance.

The genitourinary system for reasons unknown is more likely to have birth defects than any other system. The anomaly of collecting system draining the kidney represent mystifying subset of congenital anomalies. Pelviureteric junction obstruction (PUJO) is most common. Chronic obstruction can lead to stasis, urinary infection and stone formation in PUJO. Extrarenal calyces, which is characterised by presence of calyces and renal pelvis outside the renal parenchyma is one of the rare anomalies seen among the collecting system right gonadal vein drains into inferior vena cava. Its altered drainage into right renal vein is rarely seen and reported. Glut of these multiple anomalies in a single case is an extremely rare event. We hereby discuss a case of 40-year-old male patient with combination of all these anomalies and discuss the embryology, presentation and management.

Guidelines of the Italian Society of Videosurgery in Infancy for the minimally invasive treatment of pediatric nephrectomy and partial nephrectomy.

Throughout history, the pediatric laparoscopic nephrectomy was first described at the beginning of the Nineties by Erlich and colleagues in a child and by Koyle and colleagues in an unweaned patient. (...).

Tubulocystic anomalies of the mesonephric duct associated with ipsilateral renal dysgenesis.

INTRODUCTION: Renal agenesis and multicystic dysplastic kidney (MCDK) are usually associated with either an absent or atretic ureter. Occasionally, these renal anomalies may be associated with a dilated tortuous ureter, ureterocele or other cystic malformation of mesonephric duct (MND) remnants. OBJECTIVES: The objective of this study was to identify and classify anatomical variants of tubulocystic remnants of the MND, with a secondary focus on natural history and management outcomes. PATIENTS AND METHODS: A retrospective cohort study of patients seen in the study institution between 2007 and 2014 with a tubulocystic abnormality of MND structures associated with either MCDK or renal agenesis was conducted. Medical imaging and progress notes were reviewed for all patients. Data collected included anatomical information, surgical intervention, histology and outcomes of both conservatively managed and surgically resected MND remnant structures. RESULTS: Nineteen patients were identified, 5 girls and 14 boys. Median age at presentation was 4.6 years. Anomalies of the MND occurred on the left in 9 patients and on the right in 10 patients. Mean follow-up was 3.4 years. Patients fell into 3 distinct anatomical groups: Type I, including orthotopic remnants corresponding to ureteric bud structures (ureter and trigone); Type II, including ectopic MND remnants of ureteric bud structures, and Type III, including complex remnants corresponding to MND structures other than those from ureteric bud (vas, epididymis and seminal vesicles). Anomalies of structures arising from urogenital sinus and paramesonephric ducts were also identified. Most patients were asymptomatic and successfully managed conservatively. Transvesical puncture of trigonal cysts provided effective decompression in 5 patients. Partial or complete MCDK regression was seen in 7 patients, whereas MND cystic anomalies did not regress spontaneously. DISCUSSION: When MND tubulocystic structures persist along with renal agenesis or MCDK, most arise from ureteric bud structures in an orthotopic position as a ureterocele with or without a blind-ending ureter-like structure. Less commonly, ureteric bud structures insert ectopically into the urogenital tract, or tubulocystic structures arising from the remainder of the MND occur. Embryogenesis of other urogenital structures may also be abnormal, and conditions such as Zinner syndrome and obstructed hemivagina and ipsilateral renal agenesis syndrome should be considered. CONCLUSIONS: Complications are uncommon, and surgical intervention should be limited to symptomatic patients. Remnants of metanephric blastema may involute, but MND remnants persist.

Pelvic dystopia of right rudimentary multicystic dysplastic kidney as a rare cause of bedwetting in a patient with a single pelvic ectopic left kidney, and agenesis of the uterus and vagina (Mayer-Rokitansky-Küster-Hauser syndrome): a case report.

BACKGROUND: Pelvic dystopia of rudimentary multicystic dysplastic kidney as a rare cause of bedwetting in children. CASE PRESENTATION: We report the case of a 14-year-old Kazakh girl who presented with difficulty in starting the stream of urine and intermittent interruption of the urinary stream while voiding as well as bedwetting, caused by a rare congenital disease (pelvic dystopia of rudimentary multicystic dysplastic kidney). The diagnostic workup, differential diagnosis, and management, and a review of the literature are presented. Persistent since she was 2 years old, bedwetting was stressful for both the parents and child. Initially detected radiologically and endoscopically, a bladder mass was thought suspicious for ureterocele, papilloma, or mixed tumor of the urinary bladder, but surprisingly, turned out to be a pelvic dystopia of the rudimentary multicystic dysplastic kidney. Transvesical excision of this mass was performed. CONCLUSIONS: The purpose of this case report is to draw attention to the fact that a persistent case of bedwetting which does not respond to conventional therapy should be subject to further examinations to exclude surgical causes of the disease.

A refractory hypertensive patient with fibromuscular dysplasia and multicystic dysplastic kidney.

The case of a 16-year-old male patient with left renal artery stenosis due to fibromuscular dysplasia (FMD) and an atrophic kidney due to a right multicystic dysplastic kidney (MCDK) who presented with refractory hypertension is reported. On continuous Doppler imaging, the peak systolic velocity (PSV) at the stenotic site of the left renal artery was 404 cm/s. The FMD formed a "string-of-beads" appearance on computed tomographic angiography (CTA) and renal artery angiography. Percutaneous transluminal renal angioplasty (PTRA) with a balloon catheter was performed, after which the left renal artery returned to near normal, and his blood pressure decreased to within the normal range. In this case, the main cause of refractory hypertension was considered to have been renal artery stenosis due to left FMD.

Neuronal defects an etiological factor in congenital pelviureteric junction obstruction?

INTRODUCTION: Congenital pelviureteric junction obstruction (PUJO) is one of the most frequent causes of neonatal hydronephrosis. Obstruction at the PUJ has potential severe adverse outcomes, such as renal damage. While pyeloplasty has been established as the definitive treatment, the exact pathophysiology of congenital PUJO remains unknown. Recent research has proposed neuronal innervation defects as an etiological factor in congenital PUJO. We aim to study the expression of various neuronal markers in PUJO specimens compared with controls, and evaluate whether severity of renal disease or dysfunction pre-operatively is related to expression of neuronal markers in resected PUJO specimens. MATERIALS AND METHODS: All consecutive patients who underwent dismembered pyeloplasty at KK Women's and Children's Hospital, Singapore, for intrinsic PUJO from 2008 to 2012 were included. Patients with other co-occurring renal pathologies were excluded. Controls were obtained from nephrectomy patients with Wilm's tumor or other benign renal conditions during the same period. Specimens were stained immunohistochemically with neuronal markers protein gene product 9.5 (PGP9.5), synaptophysin, and S-100, and with CD-117, a marker for interstitial cells of Cajal (Table). Levels of expression of the markers were assessed semiquantitatively (decreased, increased or no change) in comparison with controls by two independent observers. Pre-operative data of patients' renal anatomical (ultrasonography measurements of renal pelvis size) and functional parameters (differential renal function measured using MAG-3 renal scans) were obtained. DISCUSSION: Thirty-eight PUJO specimens (38 renal units) and 20 controls were studied. Mean patient age at pyeloplasty was 25.3 months (2.9-167.6 months). Median pre-operative pelvic size was 25.0 mm (17.0-50.0 mm). Both PUJO specimens and controls showed great heterogeneity in distribution of innervation. All four immunohistochemical markers were not predictive of significant pre-operative renal pelvis dilation or pre-operative diminished renal function of the operated kidney. CONCLUSIONS: There exists marked variability in expression of neuronal markers synaptophysin, PGP9.5, and S-100, and CD-117 in PUJO specimens compared with controls. Our results show no clinical significance of the expression of neuronal markers in predicting degree of pre-operative renal pelvis dilation or differential renal function. The heterogeneity of expression of neuronal markers in PUJO specimens and controls in our population is at variance with prior studies. The etiology of PUJO is likely to be complex and multifactorial.