Outcomes Of Pyeloplasty Research Articles

Factors Affecting The Short Term Outcome Of Pyeloplasty In Congenital Primary Unilateral Pelvi-Ureteric Junction Obstruction In Infants and Toddlers: A Single Center trial

Factors Affecting The Short Term Outcome Of Pyeloplasty In Congenital Primary Unilateral Pelvi-Ureteric Junction Obstruction In Infants and Toddlers: A Single Center trial

Risk factors influencing the recurrence of obstruction post-pediatric pyeloplasty: a single-center prospective study

ABSTRACT Background Ureteropelvic junction (UPJ) obstruction is the leading cause of pediatric hydronephrosis. While open pyeloplasty is highly effective, a small proportion of children experience recurrent ureteropelvic junction obstruction (UPJO) necessitating repeat intervention. We aimed to identify potential risk factors for pyeloplasty failure. Methods We prospectively followed 126 children undergoing open Anderson-Hynes pyeloplasty between 2019 and 2021. Demographic, clinical, anatomical, procedural, and postoperative variables were recorded. Patients were monitored for recurrence, defined as worsening hydronephrosis and/or symptoms with diuretic renogram confirmation. Univariate and multivariate analysis identified factors associated with recurrence. Results Median age at pyeloplasty was 17 months, left side was affected in 58% and 73.8% were male. At mean 28.8 months follow-up, UPJO recurred in 9 patients (7%). The only factor significantly associated with recurrence was prolonged postoperative urinary drain leakage, specifically recurrence occurred in 50% (3/6) of cases with prolonged leakage versus 5% (6/120) without (p = 0.005). Conclusions Open pediatric pyeloplasty has a high success rate, yet a minority of patients will experience recurrence necessitating re-intervention. Prolonged urine leakage was the sole predictor of failed repair in our cohort, likely due to inflammation and perianastomotic scarring. Meticulous surgical technique and prompt leak management are vital to optimize pyeloplasty outcomes. Children at higher risk warrant close monitoring to enable early detection and renal salvage.

Long-Term Outcomes of Pyeloplasty in Children with Poorly Functioning Kidneys

Long-Term Outcomes of Pyeloplasty in Children with Poorly Functioning Kidneys

Laparoscopic Transperitoneal Pyeloplasty Outcomes in Adult Patients with Ureteropelvic Junction Obstruction

Laparoscopic Transperitoneal Pyeloplasty Outcomes in Adult Patients with Ureteropelvic Junction Obstruction

A Retrospective study to Analyze the Outcomes of Paediatric Pyeloplasty in Poorly Functioning Kidneys

Introduction: Pyeloplasty has success rate of up to 98%. We believe that paediatric pyeloplasty even in poorly functioning kidney, will result in maximum salvage of renal function. The aim of our study was to evaluate the outcome of pyeloplasty in poorly functioning kidneys with PUJO in the paediatric population. Methods: The children with PUJO with a GFR < 30 ml / min or < 30% differential function on DTPA, who underwent pyeloplasty in NU hospitals, Bengaluru over a period of 11 years 2 months, were included in our retrospective study. Anteroposterior diameters (APD) and parenchymal thickness (PT) were assessed at three months. After one year of surgery, they underwent DTPA. Outcomes analyzed were febrile UTI, the need for secondary procedures, structural and functional outcomes in operated kidneys till one year of follow-up. Results: A total of 30 patients with a mean age of four years ± 4 SD (standard deviation) with poor function on DTPA renogram (< 30%) were included in the study. 10 patients (33.33%) had a differential renal function (DRF) of 15% or less. Pre - operative mean PT was 4.7mm, mean APD was 38.5 mm, mean DRF was 19.3% and mean GFR was 17.7 ml / min. PT was increased to 6.4mm (± 2.4SD) and APD reduced to a 16.7 mm (± 10 SD) at the end of three months (p < 0.001). Increment in DRF percentage was 33.2 (± 9.4 SD) and GFR was 33.9 (± 12.5 SD) at the end of one year (p < 0.001). 13.3% of the patients had UTI, none of the study subjects required re-intervention within one year. Conclusions: The pyeloplasty for pediatric PUJO significantly improved the functional outcomes even in poorly functioning kidney, hence we recommend the pyeloplasty for selected pediatric cases of poorly functioning kidney with PUJO.

How can we measure the renal pelvic anteroposterior diameter in postnatal isolated hydronephrosis?

The anteroposterior diameter (APD) of the renal pelvis is a commonly used ultrasound parameter in the evaluation and management of hydronephrosis. It has been established that an APD value associated with pyeloplasty is around 25mm. Some believe the APD should be measured at the innermost part of the renal pelvis while others suggest that it should be done at the renal contour. However, there is no consensus on the optimal APD measurement technique including whether it should be measured supine or prone. This study compared six different techniques of APD measurements, in both supine and prone positions, and further evaluated their association with pyeloplasty. Data was obtained by retrospectively reviewing patients' charts that had initial high-grade hydronephrosis (HGH) from 2008 to 2014. We recorded the patients' demographics, ultrasound data and management choice. In the mid-renal transverse plane, the APD was measured by 2 blinded investigators, at the intra-renal, renal contour and extra-renal regions of the renal pelvis in supine and prone positions (FigureA). We compared the six APD measurements based on the outcome of management (pyeloplasty vs. conservative management). The ROC curve obtained was then used to assess the ability of various APD measurements in predicting surgical intervention. The cutoff value chosen that predicts pyeloplasty was the lowest diameter with 100% specificity. We included 129 patients (134 renal units). Forty-four renal units (42 patients) underwent pyeloplasty whereas 90 renal units (87 patients) were managed conservatively. Patients' demographics were grouped by both SFU grade and clinical outcome. Regardless of grade, the APD measurements were different in all 6 techniques. All APD measurement techniques showed good inter-rater reliability. Based on the ROC curve, all APD measurements were associated with pyeloplasty with an AUC from 0.89 to 0.91. The supine extra-renal APD measurement of 24mm was the most sensitive cutoff value. The cutoff values ranged from 18 to 27mm when including patients from all grades of hydronephrosis. The median APD measurements were significantly less for SFU grade 3 than grade 4 hydronephrosis in all positions (P<0.001 for all measurements), yet the predictive cutoff value of 24mm for the supine extra-renal was similar for both grades. APD measurements differ based on the technique, but they are all equally associated with the clinical outcome of pyeloplasty. The inter-rater reliability of all techniques were excellent. Though the median APD measurements are smaller in SFU grade 3, it appears that the cutoff for a predictive renal pelvic APD does not differ between SFU grades 3 and 4 for the supine extra-renal technique. We conclude that the technique for measuring the APD needs to be specified in studies of hydronephrosis and in any grading systems.

Comparison of continuous and interrupted suture techniques in pyeloplasty: a systematic review and meta-analysis.

Pelvi-ureteric anastomosis is a critical step to ensure good outcome of pyeloplasty. Continuous suturing technique, especially for laparoscopic surgeries, may offer faster operative time while allowing water-tight anastomosis and remains an alternative to interrupted suturing technique. There has been mixed data on comparison of outcomes of continuous and interrupted suturing techniques. This systematic review and meta-analysis aim to assess the outcomes of pyeloplasty based on continuous and interrupted suturing techniques. Following protocol registration on PROSPERO (CRD42021269706), a systematic review was performed in accordance with Cochrane Collaboration. A literature search was performed in September 2021 across Medline, EMBASE, Scopus, Cochrane Library, and ClinicalTrials.gov. Records comparing pyeloplasty outcomes between continuous and interrupted suture techniques were included. Five studies were identified for inclusion (2 prospective, 3 retrospective). Three studies involved pediatric patients. Three studies exclusively assessed laparoscopic technique. Four outcomes were meta-analyzed: operative time, length of stay, complications, and pyeloplasty failure. Interrupted sutures had longer OR time (mean difference 33.14min [95% CI 29.35-36.94], p < 0.0001) and length of stay (mean difference 1.08days [95% CI 0.84-1.32], p < 0.0001). However, there were similar complication (OR 1.73 [95% CI 0.98-3.06], p = 0.06) and failure rates (OR 1.21 [95% CI 0.43-3.43], p = 0.71) between the two suture types. The overall risk of bias in the studies was high. While limited by the number of studies available, continuous sutures for pelvi-ureteric anastomosis appear to confer benefits of faster operative time and decreased length of stay without increasing complication rates or failures.

The influence of interstitial cells of Cajal density in the outcomes of pyeloplasty in adults: A prospective analysis.

To evaluate if the density of interstitial cells of Cajal (ICC) in the ureteropelvic junction (UPJ) influences the outcomes of pyeloplasty in adults. Twenty-three patients with the diagnosis of ureteropelvic junction obstruction (UPJO) that underwent laparoscopic dismembered pyeloplasty were included. ICC density was measured using immunohistochemistry reaction for c-KIT expression in the resected UPJ segment. Pyeloplasty outcome was evaluated by patient self-report pain, urinary outflow using DTPA renogram and hydronephrosis assessment using ultrasound (US) at 12 months of follow-up. A logistic regression analysis was performed to assess the association of pyeloplasty outcomes and ICC density. Low, moderate, and high ICC density were present in 17.4%, 30.4%, and 52.2% of the patients, respectively. Complete pain resolution was observed in 100%, 85.7%, and 75% of patients with low, moderate and high ICC density, respectively (p = 0.791). DTPA renogram improved in 75%, 85.7%, and 91.7% of patients with low, moderate and high ICC density, respectively (p = 0.739). Hydronephrosis improved in 25%, 85.7%, and 91.7% of patients with low, moderate and high ICC density, respectively (p = 0.032). Patients with high ICC density have a significant amelioration of hydronephrosis after pyeloplasty. However, ICC density is not associated with functional outcomes.

Outcome of Pyeloplasty in Children with Split Renal Function Less Than 10%: A Retrospective Study

Outcome of Pyeloplasty in Children with Split Renal Function Less Than 10%: A Retrospective Study

Comparing the Effects of 2D and 3D Imaging Systems on Laparoscopic Pyeloplasty Outcomes in the Treatment of Adult Ureteropelvic Junction Obstruction.

Background: The aim of this study was to compare the efficacy, safety, and the clinical and perioperative outcomes of two-dimensional (2D) and three-dimensional (3D) laparoscopic imaging systems in adult patients undergoing laparoscopic pyeloplasty in our clinics due to ureteropelvic junction (UPJ) obstruction. Methods: A total of 46 adult patients who had undergone laparoscopic pyeloplasty due to UPJ obstruction were included in the study. Cases that had undergone the operation before January 2019 were retrospectively evaluated with the 2D imaging systems. Cases after that date were evaluated by using the 3D imaging systems, and the operative, perioperative, and postoperative findings of these patients were recorded prospectively. Patients who had undergone laparoscopic pyeloplasty were classified into two groups as the "2D group" and the "3D group." To standardize the preoperative findings, the cases that were operated by a single surgeon experienced in both 2D and 3D imaging systems were included in the study. The demographic characteristics and the clinical findings of the patients were compared between the groups. Results: A total of 41 patients were included in the study. The mean age was 27.7 ± 9.17 years. Among the patients, 23 (56.1%) were in the 2D group and 18 (43.9%) were in the 3D group. No statistically significant difference was observed between groups with regard to the demographic characteristics of the patients. According to the perioperative and postoperative findings of the patients, the duration of the operation was significantly shorter in the 3D group. Conclusion: The duration of the operation was significantly reduced in the 3D image-guided laparoscopic pyeloplasty in the treatment of UPJ obstruction of the adult, compared with 2D image-guided operations. The 3D imaging systems provide a better image quality, an important convenience in intraoperative saturation, and low rates of complication in laparoscopic pyeloplasty, and they may be used safely and effectively.

Evaluation of the Outcome of Pyeloplasty in Children with Poorly Functioning Kidneys due to Unilateral Ureteropelvic Junction Obstruction.

To analyze the outcome of upfront pyeloplasty in kidneys of children with unilateral ureteropelvic junction obstruction (UPJO). Thirty-three consecutive cases with split renal function (SRF) of ≤20% on dynamic renal scintigraphy (DRS) underwent upfront pyeloplasty with a nephrostomy tube and trans-anastomotic stent. Outcome was analyzed based on symptomatic relief, nephrostomy output, surgical complications and changes noted in pre-and post-operative findings on renal ultrasound (US), and DRS. The most common symptom was abdominal lump in <5-year age group (79%) and abdominal pain in >5-year age group (93%). Postoperatively, symptoms were relieved in all (100%), parenchymal thickness (PT) on US improved in 82% and SRF improved significantly (>5%) in 75.8% of patients. The improvement was more significant in patients with abdominal lump and large kidneys. The mean nephrostomy output showed an inverse relationship with age at pyeloplasty and a direct correlation with the change in PT and SRF. The degree of improvement in SRF also was inversely related to the age at pyeloplasty with a significantly better outcome in <2-year-age. Although age at pyeloplasty, nephrostomy output and change in PT individually showed significant correlation with change in SRF, multiple regression analysis showed PT as the only significant factor. Upfront pyeloplasty should be the first option in children with poorly functioning kidneys as it has a favorable outcome in almost all the cases with a very low incidence of complications. The degree of improvement in SRF can be predicted by the nephrostomy output and improvement in PT on US.

Can Cortical Transit Time Predict Outcomes of Pyeloplasty in Children?

Can Cortical Transit Time Predict Outcomes of Pyeloplasty in Children?

Long term outcomes following pyeloplasty for unilateral pelviureteric junction obstruction in paediatric patients

Background: Pelviureteric junction obstruction (PUJO) is the most common cause of pediatric hydronephrosis. The gold standard treatment for PUJO is Anderson hynes (AH) dismembered pyeloplasty. The parameters to assess the post-operative outcomes of pyeloplasty include reduction in the AP diameter of the pelvis and increase in parenchymal thickness. The aim of the study was to find out the long-term outcomes following pyeloplasty for Ureteropelvic junction obstruction (UPJO) in paediatric patients.Methods: A prospective study was done from September, 2014 to January, 2019. All children above the age of 2 months who presented with unilateral PUJO were included in the study. All patients underwent ultrasound of the kidneys and diuretic renogram. All patients underwent AH dismembered pyeloplasty. Success was defined as both symptomatic relief and radiographic resolution of obstruction at the last follow-up visit.Results: 60 patients with unilateral intrinsic PUJO were included in this study. Post-operatively split renal function (SRF) improved in 42 patients, remained stable in 13, and deteriorated in 5 cases. Post-operative renal drainage improved in 40 patients, remained stable in 15 and deteriorated in 5. The degree of hydronephrosis deteriorated in 5 cases but improved or was preserved in 55 cases. The renal parenchyma deteriorated in 7 cases. Overall success rate of AH dismembered pyeloplasty was 92%.Conclusions: Dismembered pyeloplasty is a safe and effective treatment of PUJO in the pediatric population. Majority of the patients had an improved split renal function, renal drainage, cortical thickness, and decreased degree of hydronephrosis.

Pyeloplasty in children with low differential renal function: Functional recoverability

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%. 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. 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. 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. 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.

Short-term outcomes of pyeloplasty vs. nephrectomy in adult patients with ureteropelvic junction obstruction and differential renal function ≤15%

Objectives To compare symptom resolution and short-term renal function after pyeloplasty or nephrectomy in adults with ureteropelvic junction obstruction (UPJO) in poorly functioning renal units (PFRU). Methods Retrospective analysis of adult patients with UPJO and differential renal function (DRF) ≤ 15% who underwent laparoscopic pyeloplasty or nephrectomy. Primary endpoints included symptom resolution and estimated glomerular filtration rate (eGFR) at 12 months. Surgical complications were compared between groups. A secondary analysis was performed comparing baseline and postoperative DRF to evaluate the PFRU recovery potential after pyeloplasty. Results Sixty-three patients were included; 19 underwent pyeloplasty and 44 underwent nephrectomy. The mean age of the cohort was 39.5 ± 13.8 years. Nephrectomy was associated with significantly higher intra-operative blood loss (p = 0.02). Operative time and length of hospital stay were not significantly different between groups. There were three complications in the nephrectomy group, and none in the pyeloplasty group (p = 0.34). Symptom resolution rates were equivalent between groups (73% vs. 76%; p = 0.78). The eGFR variation was not statistically different after pyeloplasty or nephrectomy (+6.2 vs. +0.1 mL/min/1.73m2, respectively; p = 0.18). Patients undergoing pyeloplasty had no significant change in the mean DRF (baseline 9.5 vs. 10%; p = 0.99). Conclusion Pyeloplasty can be considered for selected patients with UPJO in PFRU as an organ-sparing alternative to nephrectomy. Although there was no significant gain in mean DRF, pyeloplasty prevented further functional loss and relieved symptoms in most cases in the short-term with at least the same complication rates of nephrectomy.

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.

The prognostic value of histopathological pattern of the pelviureteric junction in the outcome of pyeloplasty in children

BackgroundThe cause of pyeloplasty failure remains unclear; therefore, increasing interest has been directed to identify the reason for dissatisfactory surgical results. Some studies attempted to investigate the role of the histopathological pattern. The aim of the work is to study the correlation between the histopathological pattern of obstructed pelviureteric junction (PUJ) segment and the outcome of pyeloplasty in children with the PUJ.MethodsFifty-four patients with pelviureteric junction obstruction (PUJO) were included in the study; patients were evaluated preoperative. All patients were operated by the same surgeon using Anderson–Hynes pyeloplasty; the resected obstructed PUJ segment examined histopathological using light microscope and image analyzer system to identify mean renal pelvis smooth muscle thickness (mRPSMT), collagen-to-smooth muscle ratio and elastin content.ResultsThe study includes 50 patients with mean age Mean 24.48 ± 15.3 months. Two patients show no improvement, while 24 improved at 3 months, 16 improved at 6 months, and 8 improved at 12 months. mRPSMT showed significant difference between improvement groups (136.02 ± 44.4, 173.47 ± 49.69 and 258.56 ± 96.82 μm), while elastin content or collagen-to-smooth muscle ratio showed no significant difference.ConclusionsOur data showed a clear relationship between mRPSMT and the time over which radiological improvement occurs; increase in mRPSMT is associated with a delay in postoperative radiological improvement time. We found no relation between elastin content nor collagen-to-smooth muscle thickness and postoperative improvement course.

&lt;p&gt;Color Doppler Ultrasonography in Evaluating the Outcomes of Pyeloplasty in Ureteropelvic Junction Obstruction&lt;/p&gt;

PurposeTo evaluate the accuracy of Color Doppler ultrasonography for diagnosing post pyeloplasty elimination of obstruction in Ureteropelvic Junction Obstruction patients.MethodologyPatients with the diagnosis of UPJO enrolled in the study and underwent open pyeloplasty. Three to 6 months after the operation, patients were recalled and underwent isotope scan as the gold standard test and renal color Doppler ultrasonography to assess the success rate of pyeloplasty.ResultsA total of 39 patients were evaluated and analyzed. The average follow-up time for patients was 9.1 months. The success rate of surgery in the study population was 100%. The mean RI of the affected side before the operation was 0.69 ± 0.01 and after the pyeloplasty, it reached to 0.65 ± 0.01. The difference between the mean RI of the affected side before and after the operation is 0.04 (P < 0.001). Age, type and severity of obstruction and the technique of surgery did not have any impact on these parameters. The difference between the RI of the affected and healthy side was termed ΔRI. ΔRI before and after the operation was 0.084 and 0.014, respectively. The decrease of ΔRI in the case of pyeloplasty is 0.07 on average (P < 0.001), which can be predicted for pyeloplasty success.DiscussionColor Doppler ultrasonography can be used as a non-invasive, fast, non-expensive, and available modality for evaluating the outcome of pyeloplasty instead of the nuclear scan or IVP.

Supranormal differential renal function in adults with ureteropelvic junction obstruction: Does it really exist?

Introduction:Some patients with ureteropelvic junction obstruction (UPJO) have supranormal differential renal function (snDRF). We aimed to study the outcomes of pyeloplasty in adult patients with UPJO and either snDRF or normal differential renal function (nDRF) and to identify preoperative factors responsible for the snDRF phenomenon.Materials and Methods:We retrospectively retrieved data for all patients who underwent pyeloplasty and had snDRF (differential renal function [DRF] ≥55%) and nDRF (DRF between 45 and 55%) preoperatively. Preoperative radiological data using computed tomography or magnetic resonance imaging were correlated with the presence of snDRF phenomenon. In addition, scintigraphic findings pre- and post-operatively were also assessed to evaluate the functional outcomes.Results:Of a total of 856 patients, 31 had snDRF (group 1) and 42 had nDRF (group 2). After a mean of 37 months’ follow-up in Group 1, 22 patients developed DRF reduction with non-obstructive pattern. Mean DRF % decreased from 59 ± 2.8 to 48 ± 13 (P < 0.0001). However, in Group 2, five patients had DRF decrease. Four patients developed snDRF phenomenon postoperatively. Increased renal pelvis volume ≥50 mm3 and increased anteroposterior pelvic diameter (APD) ≥37 mm were found to predict snDRF phenomenon. The same findings, in addition to preoperative snDRF, correlated with postoperative DRF decrease.Conclusion:SnDRF function could be expected in patients with increased renal pelvis volume and APD. The absolute value or changes in DRF are not reliable to judge treatment failure.

OUTCOME OF PEDIATRIC PYELOPLASTY IN RENAL UNITS WITH SPLIT RENAL FUNCTION LESS THAN 20%

Background: Prenatally diagnosed, hydronehprosis does not mean presence of decompensated obstruction and spontaneously improvement or resolution can occur postnatally. If obstruction persists, the split renal function (SRF) of the diseased kidney will dramatically decrease, and surgical intervention will be necessary. Objective: Evaluation of outcome of pyeloplasty in children with ureteropelvic junction obstruction (UPJO) in renal unit with split function less than 20% and to asses renal function recoverability. Patients and Methods: Cohort (historical and concurrent) study included 88 patients with UPJO with split renal function (SRF) < 20%. Preoperative patient was investigated by abdominopelvic ultrasound, magnetic resonance urography (MRU) or computerized tomography and renal isotope scan. Split renal function and T 1/2 .Preoperative and postoperative were compared. Results of the procedure were evaluated by clinical examination, abdomino-pelvic ultrasound after one month. Urine analysis with culture and sensitivity and renal isotope scan after 6 months. Results: Our study included 88 patients divided into two groups according to SRF (group 1, SRF >20% and group 2, SRF < 20%). Mean preoperative SRF was 31.34 ± 15.27%in all cases, 41.79 ± 7.03% in group 1 and 13.06 ± 4.90% in group 2, which increased postoperatively to 38.35 ± 15.61%, 46.86 ± 8.43% and 20.81 ± 7.67% respectively and this improvement was highly significant. Group 2 included 9 patient with SRF < 10%, mean preoperative SRF was 6.21 ± 2.26% which increased preoperatively to 15.04 ± 7.09% , also in the remaining 23 cases, mean preoperative SRF was 15.74 ± 2.30% increased postoperatively to 23.07 ± 6.75% . Conclusion: Poorly functioning renal unit with SRF < 20%, can show functional improvement and recoverability, so in these renal units, we should not have to rush to nephrectomy and instead of that we can proceed to pyeloplasty.