Effect of nephrostomy sheath size on renal pelvic pressure during endoscopic combined intrarenal surgery: artificial kidney model study.

BACKGROUND: This study aimed to evaluate the intrarenal pelvic pressure in endoscopic combined intrarenal surgery using an artificial kidney model. METHODS: An artificial kidney model was created using the Urovac evacuator™. Four sizes of nephrostomy sheaths (MIP-L: 25/26 Fr, MIP-M: 16.5/17.5 Fr, MIP-S: 11/12 Fr, MIP-XS: 8.5/9.5 Fr) and two sizes of ureteral access sheaths (12/14 Fr and 10/12 Fr) were installed into the model. For each combination of nephrostomy and ureteral access sheath, renal pelvic pressure was measured with and without insertion of the retrograde flexible ureteroscope. Irrigation from the nephroscope was adjusted to 40-160 mmHg using an automatic irrigation device, and the irrigation of the ureteroscope was by spontaneous dripping at 80 cmH2O. Conditions were measured six times, and the renal pelvic pressure was compared in different conditions. RESULTS: Without ureteroscope insertion through the ureteral access sheath, the renal pelvic pressure never exceeded 30 mmHg. Meanwhile, when the ureteroscope was inserted, the renal pelvic pressure increased as the nephrostomy sheath and ureteral access sheath became narrower and as the irrigation pressure increased. Intrarenal pelvic pressure exceeded 30 mmHg when the irrigation pressure was increased in 12/14 Fr ureteral access sheath when MIP-XS was used, and in 10/12 Fr ureteral access sheath when MIP-XS and MIP-S were used. CONCLUSIONS: The use of a thin nephrostomy sheath in endoscopic combined intrarenal surgery can lead to increased intrarenal pelvic pressure. Although our results are from an artificial kidney model, special care is suggested to be required when using a retrograde flexible ureteroscope simultaneously in treatment of patients.

Treatment of ureteropelvic junction obstruction in patients with renal calculi via laparoscopic pyeloplasty and flexible vacuum-assisted ureteral access sheath ureteroscopy: a multicenter retrospective observational study.

BACKGROUND: Ureteropelvic junction obstruction (UPJO) is a common obstructive disease of the urinary tract. UPJO patients commonly exhibit coexistent renal calculi. The main aim of therapy is to relieve the obstruction and remove the stones at the same time. METHODS: This retrospective study included 110 patients diagnosed with UPJO coexisting with multiple renal calculi at Shanxi Bethune Hospital and the First Hospital of Shanxi Medical University between March 2016 and January 2022. Patients were divided according to the methods used for dealing with UPJO and renal calculi. In Group A, patients underwent traditional open pyeloplasty and pyelolithotomy. In Group B, patients underwent percutaneous nephrolithotomy first and then laparoscopic pyeloplasty. In Group C, patients underwent flexible cystoscopy to remove stones and then laparoscopic pyeloplasty. In Group D, patients underwent flexible vacuum-assisted ureteral access sheath (FV-UAS)assisted flexible ureteroscopy (f-URS) and underwent laparoscopic pyeloplasty. The stones were broken up using a holmium laser. The pyeloplasty success rate, stone clearance rate, operation time, bleeding amount, complication occurrence rate, postsurgical pain, length of stay, and hospitalization cost were compared between the groups. The follow-up period was at least 2 years. RESULTS: The use of f-URS and the FV-UAS, significantly increased the renal stone clearance rate and significantly reduced the complication incidence and operation time in UPJO patients with multiple coexisting renal calculi. CONCLUSIONS: Laparoscopic pyeloplasty combined with f-URS and FV-UAS is safe and effective for treating UPJO in patients complicated by renal caliceal stones. TRIAL REGISTRATION: Retrospectively registered.

Single port robot-assisted pyeloplasty: An early comparative outcomes analysis.

BACKGROUND: The treatment paradigm for ureteropelvic junction obstruction (UPJO) has shifted towards minimally invasive pyeloplasty. A comparison Single Port (SP) and Multi Port (MP) robot-assisted pyeloplasty (RAP) was performed. METHODS: Data from consecutive patients undergoing SP RAP or MP RAP between January 2021 and September 2023 were collected and analysed. Co-primary outcomes were length of stay (LOS), Defense and Veterans Pain Rating Scale (DVPRS), and narcotic dose. The choice of the robotic system depended on the surgeon's preference and availability of a specific robotic platform. RESULTS: A total of 10 SP RAPs and 12 MP RAPs were identified. SP RAP patients were significantly younger [23 years (20-34)] than MP RAP [42 years (35.5-47.5), p < 0.01]. No difference in terms of OT (p = 0.6), LOS (p = 0.1), DVPRS (p = 0.2) and narcotic dose (p = 0.1) between the two groups was observed. CONCLUSIONS: SP RAP can be implemented without compromising surgical outcomes and potentially offering some clinical advantages.

Robotic pyeloplasty: Technological global panacea or geo-surgical nightmare?

To the Editor, Pelvi-ureteric junction obstruction (PUJO) is a well-recognised clinical entity characterised by functionally significant impairment of drainage of urine at the level of the pelvi-ureteric junction due to extrinsic or intrinsic obstruction and is encountered both by adult and paediatric urologists alike. Management of PUJO has been surgical historically, and the gold standard has been an open Anderson-Hynes dismembered pyeloplasty [...].

Retroperitoneoscopic Simple Nondismembered Pyeloplasty with Da Vinci Si Assistance to Prevent Alignment Shift.

Aims: Retroperitoneoscopic simple nondismembered pyeloplasty (SNDP) with da Vinci Si assistance was developed because of a possible risk for alignment shift after retroperitoneoscopic diamond-shaped bypass pyeloplasty (Diamond-Bypass; DP). Outcomes of SNDP and DP were compared. Materials and Methods: For SNDP, a small longitudinal incision is made on the border of the dilated pelvis and narrowed ureter at the ureteropelvic junction (UPJ). Extending this incision toward the pelvis allows identification of mucosa while maintaining the integrity of surrounding tissues that are so thin and fragile that they will not influence lumen alignment. Data for DP were obtained from a previously published article. Results: For SNDP (n = 3), mean age at surgery was 2.67 years (range: 1-4), mean operative time was 176 minutes. Mean postoperative Society of Fetal Urology (SFU) grades for hydronephrosis were 1.2, 0.7, and 0.6, 1, 2, and 3 months after stent removal, respectively. Postoperative diethylenetriaminepentaacetic acid (DTPA) was normal (n = 3). For DP (n = 5) mean age at surgery was 4.3 years (range: 1-14), mean operative time was 189 minutes. Mean postoperative SFU grades were 2.8, 2.2, and 1.6, respectively. Postoperative DTPA was normal (n = 4) and delayed (n = 1). All SNDP and DP were asymptomatic by 3 months after stent removal. Conclusion: Both SNDP and DP have favorable outcomes. If the UPJ is located at the lowest end of the renal pelvis, SNDP may improve hydronephrosis more quickly.

The learning curve of robot-assisted laparoscopic pyeloplasty in children.

To explore the learning curve of robot-assisted laparoscopic pyeloplasty (RALP) in children. The clinical data, surgical information, and postoperative complications of consecutive cases of RALP performed by the same surgeon in Shanghai Children's Hospital from January 2014 to July 2020 were retrospectively analyzed; the surgeon is a senior pediatric urologists who is proficient in laparoscopic pyeloplasty; the data consist of console time (CT), suture method when anastomosing ureteropelvic junction (UPJ), number of stitches (N), anastomosis time per stitch (tn), the average suture time per stitch (T) = (suture time of first stitch (t1) + second stitch (t2) + … + tn)/N, postoperative complications, and surgical outcome. The learning curve was depicted by cumulative sum method (CUSUM) and validated by cumulative method (CUM). Of the 88 cases, 64 cases were included in present study. Median CT was 104 (83-117) min, mean T was 109 ± 17 s. There were ten cases of Clavien-Dindo Grade I complication and two cases of Clavien-Dindo Grade IIIb complication. The median follow-up time was 237 (87-627) days. The learning curve of CT has three stages, with inflection points at 11th and 57th case, and T has two stages, with inflection points at 19th case. There was a statistically significant difference between the console time and length of stay on both sides of the inflection point (P < 0.05), but there was no statistically significant difference in age, gender, etiology, clinical manifestation, surgical outcome, and complication (P > 0.05). For a senior pediatric urologists who is proficient in laparoscopic pyeloplasty, the learning curve of RALP can be divided into three stages, preliminary exploration stage, mastery stage, and proficiency stage. It takes about 11 cases to achieve the mastery stage, and it takes about 57 cases to achieve the proficiency stage. The learning curve focused on the suture technique of the surgeon is divided into two stages, and after a learning period of 19 cases, it will reach the proficiency stage of suturing UPJ.

Experimental study of a new technique for minimally invasive percutaneous nephrolithotomy: intelligent pressure-controlled minimally invasive percutaneous nephrolithotomy.

BACKGROUND: To test the reliability and safety of a newly invented technique for minimally invasive percutaneous nephrolithotomy, intelligent pressure-controlled minimally invasive percutaneous nephrolithotomy (IPC-MPCNL). METHODS: Eighteen kidneys of nine female pigs were randomly divided into three groups. Those in Groups A and B underwent IPC-MPCNL through the new system composed of a pressure-measuring MPCNL suctioning sheath and an irrigation and suctioning platform with pressure feedback control. The infusion flow rate was 500 ml/min in Group A and 750 ml/min in Group B. Those in Group C underwent MPCNL at an infusion flow rate of 500 ml/min. The renal pelvic pressure (RPP) monitored by a ureteral catheter and that monitored by the pressure-measuring sheath in Groups A and B were compared. The RPP in Group C was monitored by a ureteral catheter. RESULTS: The RPP measured by the pressure-measuring sheath and that measured by the ureteral catheter in Group A was - 5.59 ± 1.95 mmHg and 4.46 ± 2.08 mmHg, respectively. The RPP measured by the pressure-measuring sheath and that measured by the ureteral catheter in Group B was - 4.00 ± 2.01 mmHg and 5.92 ± 2.05 mmHg, respectively. Hence, the RPPs measured by the pressure-measuring sheath in Groups A and B were consistent with those measured by the ureteral catheter. The RPP in Group C was 27.75 ± 5.98 mmHg (large fluctuations). CONCLUSIONS: IPC-MPCNL can be used to accurately monitor the RPP and maintain it within a preset safe range via suction. The new technique and the new system are safe and reliable.

Kidney collecting system anatomy applied to endourology - a narrative review.

OBJECTIVE: To evaluate the surgical anatomy of the kidney collecting system through a narrative review of the literature, highlighting its importance during diagnosis and its approach during surgical procedures for the treatment of renal stones. MATERIAL AND METHODS: We carried out a review about the anatomy of the kidney collecting system. We analyzed papers published in the past 40 years in the databases Pubmed, Embase and Scielo, and we included only papers in English and excluded case reports, editorials and opinions of specialists. RESULTS: Renal collecting system could be divided in four groups: A1 - kidney midzone (KM), drained by minor calyx that are dependent on the superior or the inferior caliceal groups; A2 - KM drained by crossed calyx, one draining into the superior caliceal group and another draining into the inferior caliceal group; B1 - KM drained by a major caliceal group independent of both the superior and inferior groups; and B2 - KM drained by minor calyx entering directly into the renal pelvis. Some details and anatomic variations of the collecting system are related to clinical and radiological aspects, particularly perpendicular calyces, interpyelocalyx space, position of calyces in relation to renal border, classification of the renal collecting system, infundibular diameter and the angle between the lower infundibulum and renal pelvis. CONCLUSION: The knowledge of intra-renal collecting system divisions and variations as the angle between the renal pelvis and lower infundibula, position of the calices in relationship with renal edge and the diameter and position of the calyces are important for the planning of minimally invasive renal surgeries.

Pediatric Robot-Assisted Laparoscopic Pyeloplasty: Where Are We Now?

PURPOSE OF REVIEW: This review aims to provide an in-depth exploration of the recent advancements in robot-assisted laparoscopic pyeloplasty (RALP) and its evolving landscape in the context of infant pyeloplasty, complex genitourinary (GU) anatomy, recurrent ureteropelvic junction (UPJ) obstruction, cost considerations, and the learning curve. RECENT FINDINGS: Recent literature highlights the safety and efficacy of RALP in treating the infant population, patients with complex GU anomalies, and recurrent UPJO which were all traditionally managed using the open approach. Cost considerations are evolving, with the potential for RALP to have a lesser financial burden. In addition, the learning curve for RALP is diminishing due to robust training programs and advances in research. RALP has become the gold standard in the treatment of UPJO in pediatric urology at many children's hospitals. Surgeon comfort and research in this space allow safe and successful reconstruction in the most challenging of cases.

Single port (SP) robotic pyeloplasty in a pediatric patient.

We began using the da Vinci single port (SP) robot for pediatric urologic surgeries at our institution due to limited access to the multiport robot. Availability of this technology has allowed us to schedule cases in a timelier fashion and increase access to minimally invasive urologic surgery for children in our area. Here, we report our technique for transperitoneal SP robotic pyeloplasty in the case of a 7 year-old boy with left ureteropelvic junction obstruction. Our technique was refined over a series of 10 patients under the age of 18. Highlights of the SP RALP technique include one 3 cm, concealed incision over the pubic tubercle, gentle frog leg positioning and burping of the boom to create optimal angle for robotic docking, and use of a "floating dock" to obtain 10 cm distance from target anatomy which is essential in smaller pediatric patients. SP pyeloplasty is safe and feasible in children and offers a concealed single incision alternative to the multiport approach.

Ureteropelvic junction obstruction in the first three months of life: is sex a prognostic factor?

OBJECTIVE: Ureteropelvic junction obstruction (UPJO) is a blockage that occurs at the point where the renal pelvis (the part of the kidney where urine collects) meets the ureter (the tube that carries urine from the kidney to the bladder). This study compared outcomes between male and female patients with UPJO. PATIENTS AND METHODS: 402 UPJO patients diagnosed and treated before the age of three months were divided into two groups: males and females. The following information was extracted: age at diagnosis, age at surgery, the parenchymal thickness of the UPJ and contralateral sides (preoperatively and at 1 and 3 years postoperatively), pelvic diameter, and kidney function. RESULTS: There were 287 male and 115 female patients (a ratio of 2.5:1). The parenchymal thickness (PTs) at diagnosis and surgery were 5(4) mm and 5(3) mm in males, respectively. In females, these values were 5(3) mm and 6(5) mm, respectively. There was a significant decrease in male PT at the time of surgery compared to diagnosis (p<0.05). After the first postoperative year, PTs were 8(4) mm and 9(4) mm in males and females, respectively, and after the third postoperative year, PTs were 9(4) mm and 10(4.75) mm in males and females, respectively. CONCLUSIONS: Among patients diagnosed with UPJO during the first three months of life, males had a more severe disease course than females. Additionally, females experienced better clinical improvement during the long-term postoperative period.

[Comparison of robotic-assisted single-incision-plus-one-port laparoscopic pyeloplasty and single-incision laparoscopic pyeloplasty in the treatment of pediatric ureteropelvic junction obstruction].

Objective: To compare the efficacy of robotic-assisted single-incision-plus- one-port laparoscopic pyeloplasty (R-SILP+1) with single-incision laparoscopic pyeloplasty (SILP) in pediatric ureteropelvic junction obstruction (UPJO). Methods: The clinical data of 47 children with UPJO who underwent surgery from October 2020 to September 2022 in the Department of Pediatric Surgery of Fujian Provincial Hospital were retrospectively analyzed. According to the surgical method chosen by parents, the children were divided into R-SILP+1 group and SILP group. Baseline data, operative time, intraoperative anastomosis time, volume of blood loss, postoperative hospitalization time, complications, total costs, preoperative and postoperative renal parenchymal thickness (PT), anterior posterior diameter of renal pelvis (APD), and differential renal function (DRF) before and after operation were compared between the two groups, and the clinical efficacy of the two kinds of operation was evaluated. Results: Among the 47 children, 27 were in R-SILP+1 group, including 16 males and 11 females, aged (6.6±3.5) years; 20 were in SILP group, including 12 males and 8 females, aged (6.5±3.5) years. The operations were successful in both groups without conversion to open operation. There were no significant differences between the two groups in baseline data, volume of blood loss, complications, APD and PT at postoperative 6 months, APD, PT and DRF at postoperative 12 months (all P>0.05). Compared with the SILP group, the operative time [(153.0±14.4) vs (189.9±32.6) minutes, P<0.001], intraoperative anastomosis time [(68.8±16.8) vs (97.5±12.0) minutes, P<0.001], postoperative hospitalization time [(6.0±1.3) vs (9.0±1.3) d, P<0.001] were shorter, but the total cost was higher[(57 390±7 664) vs (30 183±4 219) yuan RMB, P<0.001]. Conclusions: Compared with the SILP group, R-SILP+1 can achieve considerable efficacy in treating pediatric UPJO, and has certain advantages in shortening operative time, intraoperative anastomosis time, and postoperative hospitalization time. However, the cost is high.

A Pilot Study to Determine the Role of Spatulating the Ureter During Pyeloplasty in Children for Ureteropelvic Junction Obstruction in the Robotic Era.

Purpose: Spatulation during ureteropelvic junction obstruction repair was evaluated in children treated by robot-assisted retroperitoneal pyeloplasty anastomosis (RRPA). Methods: Intraoperative video recordings (IVRs) of RRPA (n = 22 ureters) performed at a single institute between 2018 and 2022 were reviewed blindly by 5 independent surgeons for perceived difficulty of suturing (DOS; 5 = impossible; 4 = difficult; 3 = tedious; 2 = slow; 1 = easy) and spatulation ranking as superior (+1), inferior (-1), or unnecessary (0). The retroperitoneal space was accessed in the lateral decubitus position using a closed technique under direct vision to avoid air leakage and subcutaneous emphysema. All subjects had a Double-J stent (4.7F) placed. Results: Subjects had similar demographics and preoperative ureter diameters. IVRs were RRPA with spatulation of the ureter on the lateral side (RRPA +SP) (n = 13) and RRPA without spatulation of the ureter (RRPA -SP) (n = 9). Overall DOS scores and coefficients of variation for time taken to place one suture were similar. Total anastomotic time was significantly shorter for RRPA -SP; 67.9 ± 8.4 minutes versus 57.9 ± 9.2 minutes, P = .01. Overall spatulation ranking was 0. Postoperative scanning showed improved drainage in 12 of 13 (92%) in RRPA +SP and 8 of 9 (88%) in RRPA -SP; differences were not significant. One anastomotic stricture in RRPA -SP required open repair. Conclusions: RRPA was quicker and more precise without spatulation. Outcomes of scanning 1 year after RRPA were similar for RRPA -SP and RRPA +SP.

Laparoscopic assisted dismembered pyeloplasty versus open pyeloplasty in UPJO with poorly function kidney in pediatrics.

BACKGROUND: The management of UPJO with poor function kidney, less than 10%, has been the subject of debate for more than a decade. Some authors have recommended nephrectomy, while others favor renal salvage (pyeloplasty). We report our experience with laparoscopic assisted pyeloplasty in pediatric patients with poorly functioning kidneys in comparison with an open approach. MATERIALS AND METHODS: A retrospective study was conducted to review 65 patients who were diagnosed with hydronephrosis and had impaired renal function due to UPJO. The study was conducted in the pediatric surgery departments of Al-Azhar University Hospital and Fattouma Bourguiba University Hospital of Monastir over a period of 20 years. Limited to pediatric patients with UPJO with ≥ Grade III hydronephrosis, antero-posterior pelvic diameter ≥ 20 mm, as well as a renal function equal to or less than 10%, was corrected by laparoscopic assisted or open pyeloplasty. RESULTS: There were 40 cases in group A who underwent laparoscopic assisted pyeloplasty, and 25 cases in group B who underwent open pyeloplasty. There were no complications or difficulties during the operation. The mean operative time in group A was 90 ± 12 min, while in group B, it was 120 ± 11 min. The renal assessment parameters significantly improved in both groups. In group A, the mean split renal function was 7.9 ± 1.3% and increased to 22.2 ± 6.3%. In group B, the mean split renal function was 8.1 ± 1.1% and increased to 24.2 ± 5.1%. However, the differences between both groups in terms of pre-operative and post-operative renal functions were statistically insignificant. CONCLUSION: Laparoscopic assisted pyeloplasty is an effective treatment for patients with poorly functioning kidneys, especially those with less than 10% function. While this surgical procedure requires shorter operative times, it yields functional outcomes that are comparable to open approach.

Risk factors for adverse outcomes after pediatric pyeloplasty: A retrospective cohort study.

PURPOSE: To identify the risk factors for adverse outcomes after pediatric pyeloplasty. METHODS: We conducted a retrospective review of all children under the age of 14 years who underwent primary pyeloplasty for unilateral ureteropelvic junction (UPJ) obstruction at a single teaching hospital in Tunisia between January 1, 2013, and December 31, 2022. RESULTS: A total of 103 patients were included. Median age of patients at surgery was 27 months (interquartile range [IQR], 13-44). On ultrasound, median renal pelvic anteroposterior diameter was 3.2 cm (IQR, 2.3-4), and the median renal cortex thickness (RCT) was 2.5 mm (IQR, 2-3.5). Median differential renal function (DRF) on preoperative radionuclide renal scan was 40% (IQR, 30-46). Postoperative adverse outcomes occurred in 28 patients (27.2%). These included 19 cases of urinary tract infections (UTIs), 11 cases of UPJ restenosis, four cases of UPJ leakage, two cases of urinoma, and two cases of diversion-related complications. Multivariate logistic regression analysis revealed two factors significantly and independently related to postoperative negative outcomes: RCT <3 mm and DRF > 50%. CONCLUSION: Our study demonstrated that preoperative RCT on ultrasound of less than 3 mm and preoperative DRF on radionuclide renal scan of more than 50% were independent risk factors for adverse outcomes following pediatric pyeloplasty. These factors could be of interest in identifying, early on, patients who will develop postoperative negative outcomes, giving them more attention and support, and explaining the prognosis to the patient and family.

Epidemiology of Infantile Ureteropelvic Junction Obstruction in the US.

OBJECTIVE: To describe sex- and diagnosis-specific comorbidities, outcomes, and secular trends associated with ureteropelvic junction obstruction (UPJO) in a large, real-world population diagnosed with hydronephrosis in infancy. MATERIALS AND METHODS: We identified all infants ≤1 year old with ≥1 claim in the Optum Clinformatics 2007-2020 nationwide population database and used univariable and multivariable Cox regression analyses to estimate associations of demographic and clinical characteristics of infants with a UPJO diagnosis with surgical status. RESULTS: Of 22,349 infants with hydronephrosis (1.1% of infants; males-1.4%, females-0.7%), 1722 (7.7%; 7.9%-males, 7.2%-females) had UPJO. Follow-up was ≥1 year in 1198 (70%) and ≥3 years in 555 (32%) cases, and UPJO repair was performed in 542 children (31.5%; 32.3%-males, 29.5%-females); 77.7% within 1 year and 97.3% within 3 years. UPJO repair was associated with prior urinary tract infection (UTI) (hazard ratio (HR) 1.41, 95% confidence interval (CI) 1.12-1.76) and South (HR 1.42, 95% CI 1.14-1.78) or Midwest (HR 1.60, 95% CI 1.26-2.04) geographic region but did not change over time. CONCLUSION: This population-based study provides a real-world view of postnatally diagnosed hydronephrosis, focusing on UPJO, for which 522 cases (∼1/3) had ≥3 years continuous coverage. UPJO-associated comorbidities were more common in females, and the frequencies of UPJO-associated surgery and comorbidities were higher than in other studies. Other than UTI, no other associated kidney or urinary tract diagnoses were associated with UPJO repair. We identified unique sex- and diagnosis-specific differences in associated comorbidities and interventions in children diagnosed with UPJO in the first year of life.

Ureteropelvic junction obstruction with polyps in children: clinical manifestations and supranormal preoperative differential renal function.

OBJECTIVE: To describe and analyze the clinical manifestation and pre-DRF of UPJO children with polyps and explore the possible influencing factors of supranormal pre-DRF. PATIENTS AND METHODS: All patients undergoing primary Anderson-Hynes pyeloplasty for UPJO due to polyp were retrospectively reviewed. Patients' characteristics, parameters of ultrasound and dynamic renograms (DR) were recorded in elaborate. Pre-DRF in groups of different age, weight, gender, pain, grade of hydronephrosis, anterio-posterior pelvic diameter (APD), length of kidney and postoperative ultrasonic parameters were compared. RESULTS: A total of 18 UPJO children with polyps were included. Five (27.78%) patients had SFU III grade of hydronephrosis. Seven (38.89%) patients were supranormal pre-DRF. All patients had pre-DRF > 40%. Drainage curve was delayed excretion in 12 (66.67%) patients and T1/2 < 20 min was in 4 (22.22%) patients. Among the 16 patients who underwent preoperative IVP examination, 15 (93.75%) patients had concentration of intrarenal pelvis contrast agent within 10 min. No significant difference in post-APD reduction rate and post-minPT increased was found between supranormal pre-DRF and non-supranormal pre-DRF groups. The supranormal pre-DRF was more likely to occur in young and low-weight children. CONCLUSION: The preoperative renal function of UPJO patients with polyps was well preserved, and 38.89% of them had supranormal pre-DRF. Patients with supranormal pre-DRF can be managed with the same strategies as those with normal renal function.