Stesura Seveso Archivio Italiano di Urologia e Andrologia 2023; 95, 1 ORIGINAL PAPER about 1/1.000-1.500 of births and it is the most common form of congenital anomalies of the kidney and urinary tract (2, 3). Until now the aetiology and pathogenesis of this anomaly are still unclear. They involved either genet- ic and/or environmental factors and the mechanism may involve abnormal innervation, impaired differentiation of smooth muscle and failure in development or recanaliza- tion of the uretero-pelvic junction (4-6). The most com- monly diagnostic tool used to detect the function of the kidney and evaluate the extent and pattern of clearance of the urine from the urinary tract is diuretic-renography. The radionuclide of choice is Technetium99m (99mTc) mercapto-acetyl-triglycine (MAG3). The study must be performed under standardised circumstances as good hydration and a transurethral catheter if needed. The study should be done after the fourth-sixth weeks of life (7, 8). The surgical intervention is indicated when there are poor drainage function after the administration of furosemide, impaired split renal function (< 40%), a decrease of split renal function of > 10% in subsequent studies and grade III or IV dilatation as defined by the Society for Foetal Urology (9). The aim of this study is to compare ureter first approach and conventional Anderson Hynes pyeloplasty in terms of feasibility, dura- tion of operation, efficacy, and complications. PATIENTS AND METHODS This prospective randomized comparative study was con- ducted at Al-Azhar university hospitals during the period from March 2022 to December 2022. Thirty-six cases with uretero-pelvic junction obstruction were assessed for eligibility. Among them, six cases were excluded due to the presence of other congenital urological anomalies (ectopic pelvic kidney or horse-shoe kidney) (n = 2), underwent previous repair (n = 3), and pregnancy (18 years) (n = 1). Thirty children were randomly divided into two groups according to a 1:1 ratio (computer-gen- erated randomization, single blind). Fifteen cases were subjected to ureter first approach pyeloplasty, and the rest were subjected to conventional Anderson Hynes (A-H) pyeloplasty (Figure 1). An informed written consent was taken from parents of patients prior to the intervention. All patients were subjected to complete history taking, Background: Uretero-pelvic junction obstruc- tion is the most common form of congenital anomaly of the kidney and urinary tract with an incidence of about 1/1.000-1.500 of births and the aetiology and pathogene- sis of this anomaly are still unclear until now. Methods: This is a prospective randomized comparative study conducted from March 2022 to December 2022. Thirty children with uretero-pelvic junction obstruction were included and ran- domly divided into two groups according to a 1:1 ratio (comput- er-generated randomization, single blind). Fifteen cases (12 males and 3 female) were subjected to ureter first approach pyeloplasty, and another fifteen (9 males and 6 female) were subjected to conventional Anderson Hynes pyeloplasty. Results: The mean age of all patients was 6.7 ± 5.4 years in ureter first approach group and 5.1 ± 4.3 years in conventional Anderson-Hynes pyeloplasty group. There were no significant differences between the two groups regarding age, gender, pres- entation, side, preoperative renogram and post-operative renogram. Also, there were no significant differences between the two groups regarding operative time (in first group 110.3 ± 12.4 and in the second group 111.2 ± 12.0 with p < 0.836), pre and post-operative complication rate. Two cases of urinary tract infections in the first group, one of them having fever, and four cases in the second group, two of them having fever (p < 0.651); four cases of loin pain in the first group and one case in the sec- ond group (p < 0.330); one case in the first group having pro- longed leakage of urine for 7 days in post-operative period (p < 0.309). However GFR and t ½ improved significantly after operation in both groups (p < 0.001). Conclusions: Ureter first approach is a simple and effective pro- cedure in children with good short term outcomes and could be done safely especially for beginners and less expert surgeons. Finally, it can overcome the problem of long ureteric stricture that may be found intraoperatively because you can shift easily to a flap procedure and complete a tension free anastomosis. KEY WORDS: Hydronephrosis; Pyeloplasty; Ureter first. Submitted 1 February 2023; Accepted 25 February 2023 INTRODUCTION In uretero-pelvic junction (UPJ) obstruction, there is an impaired urine flow from renal pelvis to proximal ureter leading to dilatation of the pelvi-calyceal system with the risk of renal damage (1). Incidence of UPJ obstruction is Comparative study between ureter first approach and conventional open Anderson-Hynes pyeloplasty in paediatric patients: A prospective randomised study Basem A. Fathi, Ahmed A. Elgammal, Tamer A. Abouelgreed, Osama M. Ghoneimy, Abdrabuh M. Abdrabuh, Mohamed A. Hindawy, Ahmed Y. Aboelsaad, Hazem Deif, Alaa Mahmoud Department of Urology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt. DOI: 10.4081/aiua.2023.11231 Summary Archivio Italiano di Urologia e Andrologia 2023; 95, 1 B.A. Fathi, A.A. Elgammal, T.A. Abouelgreed, et al. full physical examination and laboratory investigations including complete urine analysis, complete blood count, coagulation profile, urea and creatinine. In all patients, we routinely performed renal ultrasonography preopera- tively. Evaluation of patients with renal isotope scan were done in all children to confirm the obstruction and as a baseline for follow-up. Four months after pyeloplasty another renal isotope scan was done for evaluation of renal drainage and function. The protocol of this study was approved by the research ethics committee of Faculty of medicine for Girls, Al-Azhar University (FMG-IRB) (approval Number: 1279). All procedures were in accor- dance with Helsinki Declaration. Sample size was calcu- lated by Stata Corp. 2021 (Stata Statistical Software: Release 17. College Station, TX: Stata Corp LLC). Calculation was made considering an estimated incidence of uretero-pelvic junction (UPJ) obstruction of 1 in 1.000-1.500. Using confidence limits of 5%, confidence level of 95%, required minimal sample size is 16. To compensate for lost follow up cases and to increase the power of the study, sample size was increased to 30 cases divided into 15 cases for each group. Surgical technique After diagnosis, all patients underwent surgery without delay. The procedure was done in all children under gen- eral anaesthesia. Retrograde pyelography was done to determine the exact length of obstructed part, urethral catheter was fixed, and then patients were turned in later- al position. After incision of skin and muscle, the ureter was identified in the extraperitoneal space on the affected side, dissection was performed around the pelvis and proximal part of the ureter, then 2 stay sutures were placed in the upper and lower part of the pelvis. Anastomosis was done by 6-0 polyglycolic acid sutures. In the first group, ureter first approach technique was used. We performed an incision in the most dependent part of the pelvis on its lateral aspect and along the ureteral axis, then ureteric spatulation was done till the normal ureter. The apex of ureteric spatulation is sutured to the lower- most point on the lower pelvis lip using 6-0 polyglycolic acid sutures. The redundant pelvis tissue is completely dismembered from its small remaining attachment to the pelvis. Suturing is continued along one wall of spatula- tion. Double J stent was placed in an antegrade fashion. Then opposite wall of UPJ is sutured, starting again from the apex of ureteric spatulation to meet its counterpart superiorly where it was continued to sew the two edges of pelvis (Figure 2). In the second group conventional Figure 1. Consort chart of all studied cases. Figure 2. Steps of ureter first approach. A. 2 stay sutures were placed in the upper and lower part of the pelvis. B. an incision in the most dependent part of the pelvis on its lateral aspect and along the ureteral axis with spatulation of ureter to the normal lumen with suturing of the apex of ureteric spatulation to the lower-most point on the lower pelvis lip. C. cutting of the strictured segment of the proximal ureter and redundant part of pelvis. D. suturing is continued along one wall of spatulation. E. double J stent is placed in an antegrade fashion and the opposite wall of UPJ is sutured. F. final appearance after complete closure of pelvis. Archivio Italiano di Urologia e Andrologia 2023; 95, 1 Pyeloplasty in paediatric patients Anderson-Hynes technique was used (10). An L-shaped incision with developing of a flap from the redun- dant part of the renal pelvis was done. Then a stay suture was placed in the anterior wall of the ureter, ureter was spatulated laterally to the healthy part and then anastomosis was done between the ureter and pelvis using 6-0 polyglycolic acid sutures. Before completion of the anastomosis, a stent was introduced through the ureter. After completion of the anas- tomosis, a drain was placed through another stab incision. Patients were scheduled for follow-up after 1 week, then renal ultrasonography was done after 1 month. The ureteral stent was removed after 1 month and 4 months postoperatively an isotope scan was performed. Success was defined sub- jectively by symptomatic relief and objectively by renal scan results that were evaluated as improved differential renal function > 5%, good drainage and T-half < 20 minutes. Statistical analysis The collected data were revised, coded, tabulated and introduced in a PC using Statistical package for Social Science (IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp.). Student T test was used to assess the statistical significance of the difference between the two study group means. Mann Whitney Test (U test) was used to assess the statistical sig- nificance of the difference of non-parametric variables between two study groups. Chi-Square test was used to examine the relationship between two qualitative vari- ables. All reported p values were two-tailed and p < 0.05 was considered as significant. RESULTS There were no significant differences between both groups regarding age, gender, presentation, side and pre- operative renogram as shown in Table 1. Also, no signifi- cant differences were found between both groups regard- ing post op renogram as shown in Table 2 and Figures 3, 4. We found that both GFR and t ½ improved signifi- cantly after operation among both groups and no signifi- cant differences regarding changes in GFR and t ½ between the two approaches as shown in Table 3. The mean operative time for ureter first approach group was 110.3 ± 12.4 minutes, while the mean operative time for conventional Anderson-Hynes pyeloplasty group was 111.2 ± 12.0 with no significant statistical difference between the two groups (p = 0.836). There were no sig- nificant differences between both groups regarding blood loss, post-operative hospital stay and post-operative com- plications. We had two cases of UTI in the first group (one of them had fever) and four cases in the second group (two of them had fever). They were managed by proper antibiotic and antipyretic treatment until the infection resolved after 10 days. Also, there were four cases of loin pain in the first group and one case in the second group that were managed conservatively. One case in the first Table 1. Comparison of baseline parameters among studied groups. Ureter first Conventional P value approach Anderson-Hynes pyeloplasty N = 15 N = 15 Age mean ± SD 6.7 ± 5.4 5.1 ± 4.3 0.368 range 0.40 16 0.25 13 Gender male N, % 12 80.0% 9 60.0% 0.427 female N, % 3 20.0% 6 40.0% Presentation antenatal HN N, % 3 20.0% 2 13.3% 0.624 asymptomatic N, % 7 46.7% 7 46.7% 1 symptomatic N, % 8 53.3% 8 53.3% symptoms UTI N, % 5 33.3% 6 40.0% 0.705 loin pain N, % 3 20.0% 2 13.3% 0.624 Side left N, % 9 60.0% 9 60.0% 1 right N, % 6 40.0% 6 40.0% Pre op renogram Rt GFR mean ± SD 56.2 19.8 61.4 15.6 0.431 range 25 82 34 81 Lt GFR mean ± SD 56.0 17.8 50.8 20.1 0.460 range 32 81 25 81 t 1/2 mean ± SD 21.6 2.7 22.1 3.9 0.669 range 18 26 18 30 Table 2. Comparison of post-operative renograms between the two groups. Ureter first Conventional P value approach Anderson-Hynes pyeloplasty N = 15 N = 15 Post op renogram Rt GFR mean ± SD 64.1 12.4 67.3 9.4 0.434 range 34 82 47 81 Lt GFR mean ± SD 63.9 11.2 61.4 11.9 0.553 range 45 81 43 81 t 1/2 mean ± SD 9.40 2.354 8.60 1.454 0.272 range 6 14 6 11 Figure 3. Pre and post-operative GFR by both approaches. Figure 4. Pre and post-operative t1/2 by both approaches. Archivio Italiano di Urologia e Andrologia 2023; 95, 1 B.A. Fathi, A.A. Elgammal, T.A. Abouelgreed, et al. group had prolonged leakage of urine for 7 days’ post- operative and was managed conservatively after doing plain urinary tract X ray and abdomen-pelvic ultrasound showing no urinoma and the ureteric stent in place. Leakage stopped after 7 days spontaneously and there was no need for second intervention (Table 4). DISCUSSION UPJ obstruction is the most common cause of foetal kidney significant dilatation. Despite this, the clinical presentation may be delayed until adulthood (11). Many techniques for management of UPJ obstruction were mentioned through- out years and each of them had its advantages and disad- vantages. They include open pyeloplasty (either dismem- bered or flap techniques), endo-pyelotomy and laparo- scopic pyeloplasty (12). In our study we find that there was no statistically significant difference between the two groups of patients as regard the studied parameters. We believe this to be the first study to compare both tech- niques for repair of primary UPJ obstruction. In the con- ventional A-H pyeloplasty one of the problems that may happen during the operation, especially to the beginners, is the twisting of the ureter during anastomosis that may not discovered during the procedure and can result in post- operative complications as increase time of leakage of urine in the drain and lead to recurrence of stricture. Another problem is that after excision of the redundant pelvis, the segment of stricture of ureter may be long resulting in dif- ficult direct anastomosis to pelvis and requiring use of the redundant pelvic tissue for flap procedure. Those main problems could be overcome easily in ureter first approach pyeloplasty as in this technique the pelvis remained attached in its upper end until nearly the end of operation. So, it is avoided the rotation of ureter that may happen during the anastomosis and if the seg- ment of stricture is long you can shift easily to the flap procedure technique. During our search, we found only one study describing ureter first approach technique. Nayyar et al. (13) in their study that included fifty-one patients that had repair using ureter first approach technique found that there were no failures after follow up of cases that required reintervention. They concluded that ureter approach could prevent unnecessary tissue loss if a wrong incision was done and could allow good tension-free anas- tomosis in all cases especially the uncommon ones like low insertion of the ureter and long segment of UPJO. They thought that such approach can also standardize the steps of pyeloplasty surgery and could reduce the surgical mis- takes that may happen to newer surgeons or residents (13). There were multiple modifications of conventional A-H pyeloplasty aiming at reducing complications and make the procedure easier to perform (14-16). Recently, the advancements in urologic laparoscopy make feasible com- plex procedures, as pyeloplasty, that could be performed laparoscopically with the advantage of short hospital stay, less pain postoperatively and reduced morbidity but with longer operative time. Furthermore, comparative studies between open and laparoscopic dismembered pyeloplasty found that incidence of complications and functional out- come were nearly the same for both groups in adults (17- 19). Our study has some limitations including being a sin- gle center study and the short term follow up of cases. In the future we plan to perform a multicenter study with long-term follow up to obtain more information and pro- vide more impressive results. CONCLUSIONS As a conclusion we thought that ureter first approach is a simple and effective procedure in children with good short term outcomes and could be done safely especially for beginners and less expert surgeons. Also, it can over- come the problem of long ureteric stricture that may be found intraoperatively because you can shift easy to a flap procedure and complete the repair without the need of more kidney and ureter mobilization to make tension free anastomosis. Ethical Approval and Consent for Participation All procedures performed in this study complied with institutional and/or national research council ethical stan- dards as well as the 1964 Declaration of Helsinki and its subsequent amendments or similar ethical standards. Protocols and written informed consent for all partici- pants were approved by the Research Ethics Committee of the Faculty of medicine for Girls, Al-Azhar University (FMG- IRB) (approval Number: 1279). Table 3. Comparison of pre and post-operative renogram. Ureter first approach Conventional Anderson-Hynespyeloplasty Pre Post P1 Pre Post P2 P3 N = 15 N = 15 N = 15 N = 15 Rt GFR mean ± SD 56.2 19.8 64.1 12.4 < 0.001 61.4 15.6 67.3 9.4 < 0.001 0.851 range 25 82 34 82 34 81 47 81 Lt GFR mean ± SD 56.0 17.8 63.9 11.2 < 0.001 50.8 20.1 61.4 11.9 < 0.001 0.368 range 32 81 45 81 25 81 43 81 t 1/2 mean ± SD 21.6 2.7 9.40 2.354 < 0.001 22.1 3.9 8.60 1.454 < 0.001 0.196 range 18 26 6 14 18 30 6 11 P1: comparison between pre and post level after ureter first approach. P2: comparison between pre and post level after Conventional Anderson-Hynes pyeloplasty. P3: comparison of pre and post-operative changes between ureter first approach and Conventional Anderson-Hynes pyeloplasty. Table 4. Comparison of outcome among studied groups. Ureter first Conventional P value approach Anderson-Hynes pyeloplasty N = 15 N = 15 Blood loss mean ± SD 9.3 1.8 9.5 1.6 0.832 range 6 12 6 12 Hospital stay mean ± SD 1.4 0.5 1.6 0.6 0.347 range 1 2 1 3 Post op fever N, % 1 6.7% 2 13.3% 0.543 complications UTI N, % 2 13.3% 4 26.7% 0.651 prolonged leakage N, % 1 6.7% 0 0.0% 0.309 loin pain N, % 4 26.7% 1 6.7% 0.330 Archivio Italiano di Urologia e Andrologia 2023; 95, 1 Pyeloplasty in paediatric patients REFERENCES 1. Al Aaraj MS, Badreldin AM. Ureteropelvic Junction Obstruction. 2022 Jul 11. In: StatPearls (Internet). Treasure Island (FL): StatPearls Publishing; 2022. 2. Klein J, Gonzalez J, Miravete M, et al. Congenital ureteropelvic junction obstruction: human disease and animal models. Int J Exp Pathol. 2011; 92:168-92. 3. Chang CP, McDill BW, Neilson JR, et al. Calcineurin is required in urinary tract mesenchyme for the development of the pyeloureter- al peristaltic machinery. J Clin Invest. 2004; 113:1051-8. 4. 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Open dismembered tubularized flap pyeloplasty: an effective and simple operation for treatment of ureteropelvic junction obstruction. Urol Int. 2006; 76:345-7. 17. Ravish IR, Nerli RB, Reddy MN, Amarkhed SS. Laparoscopic pyeloplasty compared with open pyeloplasty in children. J Endourol. 2007; 21:897-902. 18. Mei H, Pu J, Yang C, et al. Laparoscopic versus open pyeloplas- ty for ureteropelvic junction obstruction in children: a systematic review and meta-analysis. J Endourol. 2011; 25:727-736. 19. Umari P, Lissiani A, Trombetta C, Belgrano E. Comparison of open and laparoscopic pyeloplasty in ureteropelvic junction obstruc- tion surgery: report of 49 cases. Arch Ital Urol Androl. 2011; 83:169-174. Correspondence Basem A. Fathi, MD basemhara@gmail.com basemabdalla.8@azhar.edu.eg Ahmed A. Elgammal, MD aelgammal36@gmail.com Tamer A. Abouelgreed, MD (Corresponding Author) dr_tamer_ali@yahoo.com tamerali.8@azhar.edu.eg Osama M. Ghoneimy, MD elgendyosama787@gmail.com Abdrabuh M. Abdrabuh, MD abdo197871@yahoo.com Mohamed A. Hindawy, MD hindawy78@gmail.com Hazem Deif, MD hazemdeif@yahoo.com Alaa Mahmoud, MD dralaarefaat@gmail.com Department of Urology, Faculty of medicine, Al-Azhar University, Assiut, Egypt Ahmed Y. Aboelsaad, MD aboelsaadurology@hotmail.com Department of Urology, Faculty of medicine, Al-Azhar University, Damietta, Egypt Conflict of interest: The authors declare no potential conflict of interest.