PUJO is the most common form of obstruction in the upper urinary tract.¹ Pelviureteric junction Obstruction (PUJO) is the most common cause of UPJO is defined as an obstruction to the flow of urine from the renal pelvis to the proximal ureter. It causes flank pain, hematuria, UTI, and also renal function impairment. UPJO can result from intrinsic factors (like congenital abnormalities) or extrinsic factors (such as crossing vessels). The literature highlights a prevalence of intrinsic causes, especially in antenatally diagnosed cases. Studies consistently report a higher incidence of UPJO in males, typically unilateral, with a common left-sided predominance. The age at diagnosis and surgical intervention varies, influencing outcomes.

Hydronephrosis (HDN) in children, with an incidence of 1 in 1000-2000 newborns.³ Pelviureteric junction obstruction (PUJO) is one of the most common causes of obstructive uropathy in children⁵. Pelviureteric junction obstruction is the most common congenital anomaly of the upper ureter. Intrinsic PUJO is the commonest cause of hydronephrosis⁴.

Prenatal hydronephrosis is one of the most commonly detected ultrasounds finding, affecting 1-5%of all pregnancies.

Hydronephrosis causes progressive renal impairment if left untreated. Pediatric urinary obstruction is associated with potential urinary tract infection (UTI), renal scarring, and functional deterioration and has been shown to have implications on renal function during adulthood⁹.

The conventional open Anderson Hynes dismembered pyeloplasty remains the gold standard surgical treatment with a long-term success rate exceedingly more than 90%.^4. The goal of pyeloplasty is to achieve a dependent, tension free anastomosis with good vascularity, which leads to the relief of the obstruction and also helps in improving function of the kidney ⁶ through recently minimally invasive techniques have been developed in an attempt to reduce post operative morbidity and pain, open dismembered pyeloplasty continues to be preferred surgery for correction of UPJO in developing countries like India^7. In this prospective observational study, we analyzed the outcomes of primary pyeloplasty in kidneys with unilateral ureteropelvic junction obstruction (UPJO) over a 18 months period. The ultrasound parameters are the reduction in the antero-posterior diameter (APD) of the pelvis of kidney, and increase in parenchymal thickness in a growing kidney. The definitive evidence of improved function is shown by an isotope renogram in the follow up period. It is useful to look for an objective improvement in glomerular filtration rate (GFR) and the radiotracer clearance from the pelvicalyceal system(PCS).

Despite the convenience of US in following up, debate persists regarding what parameters and values matter most. Generally the APD and CT (cortical thickness) are used as measurements, while others like pelvic cortical ratio and calyx to parenchymal ratio are proposed. The interpretation of values, however, is not straightforward.

AIMS AND OBJECTIVES

General: To systematically determine the functional outcome after pyeloplasty in children with unilateral hydronephrosis due to pelvi-ureteric junction obstruction, and the possible variables that could affect it. To evaluate the resolution of symptoms such as pain, infections, or hydronephrosis following the surgery.

Specific: To assess the impact of patient related factors (age at surgery, severity of obstruction) on surgical outcomes. To analyze the complication rates associated with unilateral pyeloplasty in pediatric patients.

To determine the long-term effectiveness of pyeloplasty in preventing further renal deterioration.

To evaluate the role of post operative, follow up protocols, including imaging and clinical assessments, in ensuring optimal outcome.

Inclusion Criteria-All children above the age of 1 month and younger than 12 years who presented to our department with unilateral pelviureteric junction obstruction and required Anderson-Hynes dismembered pyeloplasty were included in the study.

Exclusion Criteria - Children with bilateral pelviureteric junction obstruction, children with other associated renal anomalies like duplex system, horseshoe kidney, solitary kidney, recurrent PUJO or PUJ obstruction secondary to stones were excluded.

A hospital based prospective observational study was done over a period of 1 year and 6 months from February 2023 to July 2024 at Pediatric Surgery Department, Institute of Post Graduate Medical Education & Research (IPGMER), Kolkata, West Bengal, India. All the parents/guardians were informed regarding details of surgery, complications, post operative care, and follow up protocols.  Many children with antenatally diagnosed hydronephrosis who were placed under watchful waiting were also excluded from the study. Approval was taken from the Institutional Ethics Committee prior to starting the study.  40 patients with unilateral pelviureteric junction obstruction were included in this study. 26(65%) were male and 14(35%) were female.

The age of the patients ranged from 1 month to 54 months. The patient’s histories were taken and physical examination done. Baseline blood investigations were done including hemoglobin, serum urea and creatinine. Urine routine & microscopic examination as well as urine culture sensitivity were done. Ultrasounds (Renal Biometry) were done to see the anteroposterior diameter of the renal pelvis (APD) and the cortical thickness; and the ureter. In symptomatic children, we considered APD of 2 cm or more as significant. Micturating cystourethrogram (MCU) was done to rule out vesicoureteral reflux (VUR) after urine culture was sterile. Diuretic renogram with DTPA (F-15 protocol) was done to look for the function and drainage pattern of the kidneys. The DRF of affected kidney was noted, along with presence of an obstructed curve. Drainage was classified as unobstructed if T1/2 was less than10 min and the drainage curve was descending; or equivocal if T1/2 was between 10-19 minutes: and obstructed when t1/2 was more than 20 mins with obstructive curve.

Indications for surgical intervention-

• Intermittent Obstruction
• Abdominal pain or renal colic
• Recurrent infections
• Progressive dilatation of kidneys on serial ultrasound
• Delayed drainage
• Progressive loss of renal function
• Decrease of >/= 10% in serial DTPA Renogram was deemed significant. Generally, we considered 35-40% function in the hydronephrotic kidney as candidates for surgical intervention.

Those children taken up for surgery underwent AH dismembered pyeloplasty via flank approach under General anesthesia (GA). Extraperitoneal approach was adopted.

 The patients were discharged on 7th post operative day if post operative period was uneventful. DJ stent was removed after 4-6 weeks.

Follow-up examinations included serial ultrasound and diuretic renography for the assessment of both the morphological and functional outcomes at 6 months and 1 year post-operatively.

Success was defined as both symptomatic relief and radiographic resolution of obstruction. Six months post-operatively the patients were evaluated with an ultrasound of the kidneys to look for changes in AP diameter and cortical thickness and a diuretic renogram to look for the improvement in drainage and function. Same tests were repeated after 1 year.

A total of 40 patients were included. All the patients had unequivocal obstruction on diuretic renography.

PATIENTS GENDER

Table 1. Distribution of the participants according to sex

Total 65% participants were male (26 participants), and 35% were female (14 participants), making up the total study group.

AFFECTED SIDE: 

Table 2. Distribution of Affected Side Among Participants

55% of the patients presented with left sided PUJ obstruction, while 45% had pathology involving the right kidney; showing a slightly left sided predominance.

MODE OF DIAGNOSIS:              

Table 3. Mode of Diagnosis among Participants

The majority, 55% (22 participants), were diagnosed postnatally, while 45% (18 participants) were diagnosed prenatally. This indicated that postnatal diagnosis was slightly more common in the sample. Also the high percentage of antenatally diagnosed cases could be due to the fact that our institution being a tertiary referral centre. 

MEDIAN AGE OF DIAGNOSIS IN MONTHS-    

Table 4. Descriptive Summary Statistics for Age of Participants

The mean age was 18.1 months, with a median age of 16 months. The standard deviation was 14.3, indicating a wide age distribution among the participants. The minimum age was 1 month, and the maximum age was 54 months. The 95% confidence interval for the mean age ranges from 13.5 to 22.6 months.

PREOPERATIVE VARIABLES

Table 5. Summary statistics of the pre-operative renal function variables

The average preoperative APD was 5.1 cm, with a standard deviation of 1.9 cm and a 95% confidence interval ranging from 4.4 to 5.7 cm. The mean differential renal function (DRF) was 26.7%, with a standard deviation of 12.4%, and the 95% confidence interval was between 22.7% and 30.7%. The mean preoperative glomerular filtration rate (GFR) was 23.6 ml/min, with a standard deviation of 12.5 ml/min and a confidence interval of 19.6 to 27.7 ml/min. Finally, the mean global GFR was 89.7 ml/min, with a standard deviation of 21.3 ml/min and a confidence interval from 82.9 to 96.6 ml/min.

SURGICAL VARIABLES-MEAN AGE OF SURGERY IN MONTHS-

Table 6. Summary Statistics of the age of surgery

The median was 21 months and mean was 25.7 months with standard deviation of 18.3 months, indicating variability in the ages. The 95% confidence interval for the mean age ranges from 19.8 to 31.5 months. This suggested that the average age at surgery was approximately 25.7 months.

POST OPERATIVE DRF% AT 6 MONTHS & AT  1 YEAR-   

Table 7. Summary statistics of the post-operative DRF at six months and 1 year

At six months, the mean DRF was 30.1% with a standard deviation of 10.9%, and the 95% confidence interval ranges from 26.6% to 33.6%. By one year, the mean DRF slightly increases to 30.9%, with a standard deviation of 11.5% and a confidence interval of 27.2% to 34.6%.

POST OPERATIVE APD AT 6 MONTHS &AT 1 YEAR-

Table 8. Summary statistics of the post-operative APD at six months and 1 year

At six months, the mean APD was 4.2 cm, with a standard deviation of 1.8 cm and a 95% confidence interval of [3.6, 4.8] cm. By one year, the mean APD decreases slightly to 3.9 cm, maintaining the same standard deviation of 1.8 cm, with a confidence interval of [3.4, 4.5] cm. These results indicate a small reduction in APD from six months to one year, with variability in the measurements at both time points.

INDICATIONS FOR UNDERGOING SURGERY-                                                                                                                                                                                    

Table 9. Distribution of the participants according to the presenting problem

The most common presentation was an abdominal pain, alone or with presence of a lump observed in 12 cases (30.0%), followed by abdominal lump in 10 cases(25%)followed by recurrent urinary tract infections (8 cases, 20.0%) . Incidental findings were noted in 6 cases (15.0%), while abdominal pain alone was seen in 5 cases (12.5%). Abdominal lump with fever accounted for 3 cases (7.5%), and failure to thrive was the least common, reported in 1 case (2.5%).

Table 10. Summary statistics of the post-operative DRF at six months and 1 year

At six months, the mean DRF was 30.1%, with a standard deviation of 10.9% and a 95% confidence interval ranging from 26.6% to 33.6%. By one year, the mean DRF increases slightly to 30.9%, with a standard deviation of 11.5% and a confidence interval of 27.2% to 34.6%. These findings indicate a small improvement in DRF over the one-year period, along with some variability in the measurements at both time point.

Table 11. Summary statistics of the post-operative GFR at six months and 1 year

At six months, the mean GFR was 30.1 ml/min, with a standard deviation of 12.3 ml/min and a 95% confidence interval of [26.2, 34.1] ml/min. By one year, the mean GFR shows a slight increase to 31.2 ml/min, with a standard deviation of 13.6 ml/min and a confidence interval of [26.8, 35.6] ml/min. These results suggest a modest improvement in GFR from six months to one year, along with variability in the measurements at both intervals.

Table 12. Distribution of the participants according to the post-operative GFR category at six months and 1 year

At both six months and one year, 8 patients (20%) fall into the GFR category of less than 20%, while 32 patients (80%) have a GFR greater than 20%. This indicates a distribution of GFR categories over the one-year period, with a majority of patients maintaining a GFR above 20%.

At The End Of 1 Year Follow Up Post Op DRF Improved >5% In 40% Patients, Remained static In 55 %Cases & Deteriorated In  2 % Patients.

Table 13. Distribution of the participants according to the different categories of the post-operative change of GFR at six months and 1 year

The GFR improved from six months to one year, raising from 30% to 40%. Meanwhile, the percentage of patients with static GFR decreased slightly, while those who deteriorated increased from 2.5% to 5%. Overall, the data suggest a positive trend in GFR improvement over the one-year period.

APD & DRF changes in 1 year

Observations:

1. Trend: The points are scattered without a clear linear trend, suggesting a weak or no direct relationship between APD and DRF changes at 1 year.
2. Cluster: Most of the data points are clustered near the centre (around 0 for both axes), indicating minimal changes in both parameters for many individuals.
3. Outliers: There are some data points farther from the cluster, indicating cases where the changes in either DRF or APD (or both) were more pronounced.
4. Range:

• DRF Change: Spans approximately from -10 to +20.
• APD Change: Spans approximately from -4 to +1.

Based on the visual distribution, the relationship appears weak or inconsistent, but statistical analysis (e.g., correlation coefficient) would provide a more precise interpretation.

Comparison to the 1-Year Plot:

• The range of DRF change in this plot is slightly wider (extending to -20), while the APD change range is narrower compared to the 1-year plot.
• Both scatter plots lack a clear relationship, although the clustering patterns are slightly different.

Key observations of the correlation matrix

Pre-op DRF and Post-op DRF: Preop DRF vs. Post OP DRF six months (0.868): Very strong positive correlation, suggesting that preoperative differential renal function is strongly associated with postoperative DRF at six months.

Global GFR:

Preop Global GFR vs. Post OP APD 6 months (0.435): Moderate positive correlation, indicating a moderate association between preoperative global GFR and postoperative APD.

Table 13. Table of complications

Thus, complications were encountered in 17 out of 40 patients(42.5%). most commonly encountered complication was lumbar hernia found in 7.5% of the patients.5 out of 40 patients suffered from major complications (12.5%) and required further surgery.12 out of 40 suffered from minor complications.(30%).

Intraoperative findings-aberrant lower polar crossing vessels as a cause for pelviureteric junction obstruction was found in 3 patients (7.5%).

In case of UPJO theddismembered pyeloplasty has been proved to be the best mode of treatment for ureteropelvic junction obstruction.¹⁹ The procedure eliminates the diseased segment and reestablishes the continuity of urinary tract.²⁰ Significant improvement in surgical techniques, refinements of surgical materials and sutures enable us to obtain a nearly water tight anastomoses.^21,22 In our study, 65% of participants were male and 35% were female. Other studies also show that obstruction is more commonly found in boys than in girls, especially in the newborn period, when the ratio exceeds 2:1.¹²

According to our study, left UPJO was present in 55% (n=22) and right sided UPJO was present in 45% (n=18). Studies show a 66% left sided UPJO.⁸ Other studies show that left-sided lesions predominate, particularly in the neonate, up to approximately 67%. This is in concordance with our study.

In our study, the most common presenting complaint was flank pain, alone with presence of abdominal lump found in 12 cases (30%). The next presenting complaint was abdominal lump found in 10 cases (25%). This was followed by recurrent febrile UTI.

In our study the mean preoperative DRF was 26.7%. A recent study, which utilized DRF<40% as the main indication for pyeloplasty, regardless of HN grade &APD, showed a much higher febrile UTI rate of 12.5% for patients followed non surgically, when compared to previous studies.³¹This abnormally higher UTI rate seen, was most likely secondary to waiting for too long to allow renal function loss to occur.

In our study, at 6 months, the post operative GFR improved in 12 patients (30%), the post operative GFR remained stable in 27 patients (67.5%) and deteriorated in 1 case (2.5%).

When the post operative GFR at 1 year was studied, results showed that post operative GFR improved in 16 cases (40%), remained stable in 22 cases (55%) and deteriorated in 2 patients. (5%).

The degree of hydronephrosis deteriorated in 2 cases but improved or was preserved in 38 cases.

While studying the effects of patients age,affected side,clinical features on the functional outcome of dismembered pyeloplasty,no statistically significant correlation was found.(p value >0.05). This is in concordance with other studies. There was no statistically significant difference in improvement in renal function by age group or patient presentation. Preoperative DRF was the only statistically significant predictor of improvement in renal function after pyeloplasty.

23 patients (57.5%) had uneventful post operative course while 17 patients (42.5%) suffered from some sort of complication. When these results were compared with other national studies, the complication rate was higher. This may be because the surgeries were performed by not one surgeon but by different surgeons of the surgical team, which included trainee paediatric surgeons as well. The most commonly encountered complications were lumbar hernia in 3 patients, high drain output in 2 patients which resolved with conservative treatment, post operative subacute intestinal obstruction in 2 children, ileus in 2 children and UPJ restenosis in 2 patients.

In our study, there were 2 cases of failure or recurrent PUJO. Out of these 2 cases, one underwent redo pyeloplasty and one unfortunate case ended up in nephrectomy as kidney parenchymal tissue had become papery thin.

Thus, Anderson Hynes Pyeloplasty which is the gold standard treatment for UPJO needs to be followed up with radionuclide scan to know the post operative function of the kidney,the only way to assess the functional status of the kidney.The need for redo pyeloplasty is based on symptoms and the deteriorating renal function.

However, one result that demands mention is the fact that the preoperative mean APD was 5.1 cm. Where as mean APD at the end of 6 months post-operatively was 4.2 cm and it was 3.9 cm at the end of 1 year. There was only a modest decrease. May be surgeons performed limited excision of pelvis of such dimensions.

The most commonly encountered complication was lumbar hernia in 3 patients. (7.5%)

Recommendations Of Our Study

• Hydronephrosis that has resolved postnatally does not merit prolonged follow up & has satisfactory outcome.²⁶
• The presence of two normal post natal renal ultrasound excludes presence of significant renal disease.
• We recommend that any infant with hydronephrosis be immediately referred to a surgeon for appropriate intervention.
• We suggest that surgery be considered in patients with obstructed hydronephrosis,and either reduced DRF or its worsening on repeat evaluation.

• While most experts suggest that pyeloplasty be considered in patients showing obstructed drainage & DRF<40%, others propose surgery at DRF<35% or an obstructed renogram with prolonged t1/2 >20 minutes.²⁸
• However, waiting for renal function to decrease before considering pyeloplasty is not warranted,since function does not improve even when the obstruction is corrected & drainage times improve.

Limitations Of This Study

In spite of every sincere effort, my study has lacunae. The notable shortcomings of this study are:

• Small number of study sample
• Non randomized study design
• Follow up period was only one year.
• The surgeries were performed not by a single surgeon but by different surgeons in different learning curve.
• The study was carried in a tertiary care hospital:  so, hospital bias cannot be ruled out.

In our study, at the end of 1 year, improvement in renal function occurred in 16 (40%) patients, the GFR remained static in 22 (55%) of patients and GFR deteriorated in 2(5 %) of patients. Age at surgery, side of affection or clinical features showed no statistically significant correlation with the functional outcome after surgery. Majority of patients had small improvement in DRF over 1 year period. There was a positive trend in GFR improvement over 1 year period. These findings can be used to counsel parents regarding the potential effects of UPJO and Pyeloplasty.

However, what can be objective criterion for surgery remains matter of debate. Using only DRF deterioration has its own problems. Thus, what should be the exact objective criterion for undergoing pyeloplasty is also a matter of debate. Further randomized control trials with a more number of cases are needed.

1. Grignon A, Filiatrault D, Homsy Y, Robitaille P, Filion R, Boutin H, Leblond R. Ureteropelvic junction stenosis: antenatal ultrasonographic diagnosis, postnatal investigation, and follow-up. Radiology. 1986 Sep;160(3):649-51.
2. Bansal R, Ansari MS, Srivastava A, Kapoor R. Long-term results of pyeloplasty in poorly functioning kidneys in the pediatric age group. Journal of pediatric urology. 2012 Feb 1;8(1):25-8.
3.  Maheshwari R, Ansari MS, Mandhani A, Srivastava A, Kapoor R. Laparoscopic pyeloplasty in pediatric patients: the SGPGI experience. Indian Journal of Urology. 2010 Jan 1;26(1):36-40.
4. Ahmed S, Crankson S, Sripathi V. Pelviureteric obstruction in children:Conventional pyeloplasty is superior to endo-urology. Australian and New Zealand journal of surgery. 1998 Sep;68(9):641-2.
5. Capello SA, Kogan BA, Giorgi LJ, Kaufman RP. Prenatal ultrasound has led to earlier detection and repair of ureteropelvic junction obstruction. The Journal of urology. 2005 Oct;174(4 Part 1):1425-8.
6. Göğüş Ç, Karamürsel T, Tokatli Z, Yaman Ö, Özdiler E, Göğüş O. Long-term results of Anderson-Hynes pyeloplasty in 180 adults in the era of endourologic procedures. UrologiaInternationalis. 2004 Jun 25;73(1):11-4.
7. Moreira-Pinto J, Osório A, Vila F, de Castro JL, Réis A. Dismembered pyeloplasty for ureteropelvic junction syndrome treatment in children. African Journal of Paediatric Surgery. 2012 May 1;9(2):98-101.
8. Ibrahim Selmy G, Mohamed Salih ES, Salah El-Din Zykri M, Abd El-Maksoud AE. outcome of pediatric pyeloplasty in renal units with split renal function less than 20%. Al-Azhar Medical Journal. 2019 Oct 1;48(4):489-500.
9. Peters CA. Obstruction of the fetal urinary tract. J Am Soc Nephrol. 1997 Apr;8(4):653-63. doi: 10.1681/ASN.V84653. PMID: 10495796.
10. Abbas T, Elifranji M, Al-Salihi M, Ahmad J, Vallasciani S, Elkadhi A, Özcan C, Burgu B, Akinci A, Alnaimi A, Salle JP. Functional recoverability post-pyeloplasty in children with ureteropelvic junction obstruction and poorly functioning kidneys: systematic review. Journal of pediatric urology. 2022 Oct 1;18(5):616-28.
11. Bowen DK, Mittal S, Aghababian A, Eftekharzadeh S, Dinardo L, Weaver J, Long C, Shukla A, Srinivasan AK. Pyeloplasty is a safe and effective surgical approach for low functioning kidneys with ureteropelvic junction obstruction. Journal of Pediatric Urology. 2021 Apr 1;17(2):233-e1.
12. Inugala A. Long term outcomes following pyeloplasty for unilateral pelviureteric junction obstruction in paediatric patients. International Surgery Journal. 2021 Sep 28;8(10):3055-9.
13. Sinha A, Bagga A, Krishna A, Bajpai M, Srinivas M, Uppal R, Agarwal I. Revised guidelines on management of antenatal hydronephrosis. Indian journal of nephrology. 2013 Mar 1;23(2):83-97.
14. Kapoor R, Gupta A, Abbey P, Sethi RS, Yadav PS, Choudhury SR, Chadha R. Evaluation of the outcome of pyeloplasty in children with poorly functioning kidneys due to unilateral ureteropelvic junction obstruction. Journal of Indian Association of Pediatric Surgeons. 2022 Sep 1;27(5):544-52.
15. Babu, R., & Sai, V. (2010). Pelvis/cortex ratio: A sonographic marker of pelvi ureteric junction obstruction in children. Indian journal of urology : IJU : journal of the Urological Society of India, 26(4), 494–496. https://doi.org/10.4103/0970-1591.74437
16. Babu, R., Rathish, V. R., & Sai, V. (2015). Functional outcomes of early versus delayed pyeloplasty in prenatally diagnosed pelvi-ureteric junction obstruction. Journal of pediatric urology, 11(2), 63.e1–63.e635.
17. https://doi.org/10.1016/j.jpurol.2014.10.007Menon, P., Rao, K. L., Bhattacharya, A., & Mittal, B. R. (2016). Outcome analysis of pediatric pyeloplasty in units with less than 20% differential renal function. Journal of pediatric urology, 12(3), 171.e1–171.e1717.
18. Kord, E., Neeman, B. B., Perez, D., Chertin, B., Zisman, A., &Neheman, A. (2023). The effect of ureteropelvic junction obstruction and pyeloplasty on somatic growth during infancy. Therapeutic advances in urology, 15, 17562872231172835. https://doi.org/10.1177/17562872231172835
19. Poulakis, V., Witzsch, U., Schultheiss, D., Rathert, P., & Becht, E. (2004). Die Geschichte der operativenBehandlung der Harnleiterabgangsstenose (Pyeloplastik). Von Trendelenburg (1886) biszurGegenwart [History of ureteropelvic junction obstruction repair (pyeloplasty). From Trendelenburg (1886) to the present]. Der Urologe. Ausg. A, 43(12), 1544–1559. https://doi.org/10.1007/s00120-004-0663-x
20. Sutherland, R. W., Chung, S. K., Roth, D. R., & Gonzales, E. T. (1997). Pediatric pyeloplasty: outcome analysis based on patient age and surgical technique. Urology, 50(6), 963–966. https://doi.org/10.1016/S0090-4295(97)00397-X

1. Smith, K. E., Holmes, N., Lieb, J. I., Mandell, J., Baskin, L. S., Kogan, B. A., & Walker, R. D., 3rd (2002). Stented versus nonstented pediatric pyeloplasty: a modern series and review of the literature. The Journal of urology, 168(3), 1127–1130. https://doi.org/10.1016/S0022-5347(05)64607-1
2. Ahmed, S., &Crankson, S. (1997). Non-intubated pyeloplasty for pelviureteric junction obstruction in children. Pediatric surgery international, 12(5-6), 389–392. https://doi.org/10.1007/BF01076947
3. Tayib A. M. (2004). Long term results of pyeloplasty in adults. Saudi medical journal, 25(3), 363–366.
4. Janetschek, G., Peschel, R., & Bartsch, G. (2000). Laparoscopic Fengerplasty. Journal of endourology, 14(10), 889–893. https://doi.org/10.1089/end.2000.14.889
5. Inagaki, T., Rha, K. H., Ong, A. M., Kavoussi, L. R., & Jarrett, T. W. (2005). Laparoscopic pyeloplasty: current status. BJU international, 95 Suppl 2, 102–105. https://doi.org/10.1111/j.1464-410X.2005.05208.x
6. Ismaili, K., Avni, F. E., Wissing, K. M., & Hall, M. (2004). Long-term clinical outcome of infants with mild and moderate fetal pyelectasis: validation of neonatal ultrasound as a screening tool to detect significant nephrouropathies. The Journal of pediatrics, 144(6), 759-765.
7. Nguyen, H. T., Herndon, C. A., Cooper, C., Gatti, J., Kirsch, A., Kokorowski, P., ... & Campbell, J. B. (2010). The Society for Fetal Urology consensus statement on the evaluation and management of antenatal hydronephrosis. Journal of pediatric urology, 6(3), 212-231.
8. Heinlen, J. E., Manatt, C. S., Bright, B. C., Kropp, B. P., Campbell, J. B., & Frimberger, D. (2009). Operative versus nonoperative management of ureteropelvic junction obstruction in children. Urology, 73(3), 521-525
9. Muradi T, Turkyilmaz Z, Karabulut R, et al. Our experience of operated pediatric ureteropelvic junction obstruction patients. Urologia Journal. 2023;90(4):720-725. doi:10.1177/03915603211046161
10. Siddique, M., Pansota, M. S., Saleem, M. S., &Attique-ur-Rehman (2014). Outcome of pyeloplasty in children. Journal of Ayub Medical College, Abbottabad : JAMC, 26(1), 71–75.
11. Li, B., McGrath, M., Farrokhyar, F., & Braga, L. H. (2020). Ultrasound-Based Scoring System for Indication of Pyeloplasty in Patients With UPJO-Like Hydronephrosis. Frontiers in pediatrics, 8, 353. https://doi.org/10.3389/fped.2020.00353
12. Chertin, B., Rolle, U., Farkas, A., & Puri, P. (2002). Does delaying pyeloplasty affect renal function in children with a prenatal diagnosis of pelvi-ureteric junction obstruction?. BJU international, 90(1), 72–75. https://doi.org/10.1046/j.1464-410x.2002.02829.x
13. Sharifiaghdas, F., Amini, J., Narouie, B., Rouientan, H., Ahmadzade, M., & Emami, M. A. (2024). Pediatric Pyeloplasty in the Poor Function Kidneys: Does Surgical Success Guarantee Improvement in Renal Function? Single-Center Experience and Review of Literature. Urology journal, 21(1), 52–56. https://doi.org/10.22037/uj.v20i.7768
14. Tireli, G. A., Eliçevik, M., Demirali, O., Unal, M., & Sander, S. (2005). Moderate approach to the antenatally diagnosed unilateral ureteropelvic junction obstruction: experience with 93 patients. Pediatric surgery international, 21(8), 621–624. https://doi.org/10.1007/s00383-005-1480-z
15.  Reilly P, Aurell M, Britton K, Kletter K, Rosenthal L, Testa T. Consensus on diuresis renography for investigating the dilated upper urinary tract. Radionuclides in Nephrourology Group. Consensus Committee on Diuresis Renography. J Nucl Med. 1996;37(11):1872-6. 9.
16.  Palmer LS, Maizels M, Cartwright PC, Fernbach SK, Conway JJ. Surgery versus observation for managing obstructive grade 3 to 4 unilateral hydronephrosis: a report from the Society for Fetal Urology. J Urol. 1998;159(1):222-8.
17. PSOOY, K., PIKE, J. G., & LEONARD, M. P. (2003). Long-term Followup of Pediatric Dismembered Pyeloplasty: How Long is Long Enough? Journal of Urology, 169(5), 1809–1812. https://doi.org/10.1097/01.ju.0000055040.19568.ea (Original work published May 1, 2003)