Comparative Study of a Modified Suture Technique with a Minimal Renal Pelvis Incision in Paediatric Hydronephrosis Treatment

Comparative Study of a Modified Suture Technique with a Minimal Renal Pelvis Incision in Paediatric Hydronephrosis Treatment | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Comparative Study of a Modified Suture Technique with a Minimal Renal Pelvis Incision in Paediatric Hydronephrosis Treatment Jiaqi Dong, Yiming Yuan, Jiajing Qiu, Lizhong Shi, Tonglie Ni, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7622736/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Laparoscopic pyeloplasty (LP) is an effective treatment for ureteropelvic junction obstruction (UPJO), but research on reducing renal pelvis incision size and improving suture techniques is limited. Purpose To compare LP with a modified suture and minimal renal pelvis incision versus standard LP for treating paediatric UPJO. Methods A retrospective analysis of 120 paediatric UPJO patients who underwent surgery at the Children's Hospital of Nanjing Hospital from January 2022 to June 2024 was conducted. Among the 120 patients, 103 were male, 17 were female, and the median age was 68.0 months. One hundred cases were left-sided, and 20 were right-sided. The modified group (MG) received LP with a minimal renal pelvis incision and modified suture technique, whereas the control group (CG) underwent standard LP. There were no significant differences between the groups in terms of sex, age, side, or preoperative hydronephrosis (P > 0.05). Surgical and follow-up outcomes were compared. Results All surgeries were successful without conversion to open surgery. Compared with the CG, the MG had shorter surgery times, less blood loss, shorter hospital stays, and less postoperative haematuria (P < 0.05). One case (1.59%) of D‒J tube blockage occurred in the MG, whereas seven cases (12.28%) occurred in the CG, with significant difference (P 0.05). The reoperation rate was 1.59% for the MG and 1.75% for the CG (P > 0.05). Conclusion Compared with standard LP, LP with a modified suture and minimal renal pelvis incision offers advantages in terms of surgery time, blood loss, hospital stay, and incidence of postoperative haematuria. The reoperation rate and APD recovery were similar between the groups, and the MG had a lower incidence of D‒J tube blockage, making this technique a viable option for treating paediatric UPJO. Children UPJO Small Renal Pelvis Incision Modified Suture Laparoscopic Pyeloplasty Figures Figure 1 Figure 2 Figure 3 Introduction Paediatric congenital hydronephrosis, typically identified through prenatal ultrasound (US) screening or postnatal ultrasound when symptoms appear, is characterized by dilation of the renal collecting system, with ureteropelvic junction obstruction (UPJO) being the most common underlying cause. Since Schuessler et al. first introduced laparoscopic pyeloplasty (LP) in 1993【1】, this technique has gained widespread clinical adoption and has gradually replaced open surgery as the preferred treatment for paediatric UPJO. LP not only offers comparable long-term success rates to open surgery but also provides advantages such as improved cosmetic outcomes, shorter hospital stays, and faster recovery times, especially in developing countries where robotic surgery is less prevalent【2, 3】. Despite its advantages, LP still presents technical challenges, especially in achieving safe, tension-free renal pelvis-ureter anastomosis, which requires advanced suturing skills. The technique for suturing the lowest point of the renal pelvis and ureter directly impacts treatment outcomes for patients and the prognosis of hydronephrosis, requiring high surgical expertise【4】. This study innovatively improves the suturing technique and reduces the renal pelvis incision size, enhancing surgical outcomes, shortening operative time, and reducing D-J tube blockage. To our knowledge, this is the first study to examine the impact of renal pelvis incision size and modified suturing technique. This comparison between LP with a minimal renal pelvis incision and standard LP offers valuable insights for managing paediatric UPJO. Materials and Methods 1.1 General Information A retrospective analysis was conducted on the clinical data of 120 children with congenital hydronephrosis treated surgically in the Department of Urology at the Children's Hospital of Nanjing Medical University, from January 2022 to June 2024. All of them underwent urologic ultrasound, magnetic resonance urography (MRU), and voiding cystourethrography (VCUG) preoperatively, and some of them underwent renal scintigraphy. The 63 children who underwent LP with a small renal pelvis incision (incision ≤ 1.5 cm) were designated as the SIG, while the 57 children who underwent standard LP (incision > 1.5 cm) were designated as the CG. The guardians of the patients signed an informed consent for the surgery before the operation, and the study was approved by the Medical Ethics Committee of Children's Hospital of Nanjing Medical University, Ethics No. 202503017-1. 1.2 Inclusion and Exclusion Criteria The inclusion criteria were as follows: ① symptomatic obstruction (costovertebral pain, urinary tract infection). ② Impaired renal function (renal function 10% decrease in renal function during follow-up. ④ Ultrasound showing an increased anterior‒posterior diameter of the renal pelvis. ⑤ SFU grade III or IV dilation. ⑥ Children aged 0–16 years. ⑦ Patients were randomly allocated to both groups. The exclusion criteria were as follows: ① other causes of hydronephrosis, such as urinary tract stones, posterior urethral valves, or distal ureteral stenosis; and ② significant underlying diseases or other surgical comorbidities. ③ Bilateral hydronephrosis. ④ Failure to attend regular follow-up appointments. 1.3 Methods Surgical procedure in the MG : After anaesthesia, a urinary catheter was inserted, and the patient was positioned laterally. The skin was disinfected, and sterile drapes were applied. A 5 mm trocar was inserted at the umbilicus, with two more screws placed above and below. The posterior peritoneum was opened with an ultrasonic scalpel. The renal pelvis and ureteric junction were freed, and two suspension sutures were placed for support. The renal pelvis–ureteric junction was resected, and a 1.0-1.5 cm segment of the renal pelvis was resected for anastomosis (Fig. 1 A, Fig. 2 ). A longitudinal incision was made on the lateral wall of the ureter. Rather than starting the anastomosis at the lowest point of the renal pelvis and ureteric junction, the first suture was placed one needle's distance above the lowest point of the renal pelvis and ureteric incision (Fig. 1 B). The posterior wall of the renal pelvis and ureter was continuously sutured (Fig. 1 C), and a D‒J tube was inserted. The lowest point of the renal pelvis and ureteric junction was sutured (Fig. 1 D, a, b). The anterior wall of the renal pelvis and ureter was then continuously sutured (Fig. 1 E). After completion, the renal pelvis-ureter junction was positioned at the lowest point without any torsion. The trocar was withdrawn, and the incision was sutured. Surgical procedure in the CG : After anaesthesia, positioning, trocar insertion, and exposure of the renal pelvis and ureteric junction were similar to those of the MG. Both were freed, and two suspension sutures were placed for support. The renal pelvis–ureteric junction was resected, and a 3 cm incision was made on the renal pelvis for anastomosis (Fig. 3 ). The anastomosis started from the lowest point of the renal pelvis, and a ureteric incision was made. Continuous or interrupted sutures were used to repair the posterior wall of the renal pelvis and ureter, and a D‒J tube was placed. Continuous or interrupted sutures were used to repair the anterior wall of the renal pelvis and ureter. After suturing, the renal pelvis-ureter junction was positioned at the lowest point without any torsion. The incision was sutured after the trocar was withdrawn. 1.4 Postoperative Management Postoperative observation included monitoring for symptoms such as abdominal distension, lumbar pain, haematuria, and urinary difficulties. A urinary catheter was typically retained for 3–5 days before removal. Routine prophylactic antibiotics were administered for 2‒3 days. One month after discharge, the D‒J tube was removed via cystoscopy. 1.5 Outcome measures and efficacy evaluation Surgical time (minutes), intraoperative blood loss (millilitres), postoperative haematuria duration (days), and postoperative hospital stay were compared between the two groups. Additionally, the success rate of the procedure and occurrence of postoperative complications (such as urinary leakage, incision infection, fever, and D‒J tube blockage) were assessed. All patients underwent ultrasound follow-up 2 months after surgery, with subsequent follow-ups every 6 months. Surgical success criteria included clinical symptom relief, stable or improved renal function, and improvement in the anterior‒posterior diameter of the renal pelvis. 1.6 Statistical methods The data were analysed using SPSS ® 25.0. Categorical variables are expressed as numbers and were compared using the Chi-square test or Fisher’s exact test, where appropriate. Data between groups were compared using Student's t test or the Chi-square test. Nonnormally distributed data are expressed as median ranges and were compared using the Mann‒Whitney test. All the statistical tests were two-sided, with the significance level set at p < 0.05. 2.1 General information This study included 120 children, consisting of 103 males and 17 females, with a median age of 68.0 months (range: 15.0–102.8 months). Among them, 100 cases were left-sided, and 20 were right-sided. Forty-six patients were prenatally diagnosed with asymptomatic hydronephrosis, whereas 74 patients had symptomatic hydronephrosis. The MG included 63 children, with an age range of 1.9–174 months and an average age of 67.75 ± 48.97 months; 52 males and 11 females were included. The CG consisted of 57 children, with ages ranging from 1.4–165 months and an average age of 64.48 ± 52.19 months; 51 males and 6 females were included. There were no significant differences between the MG and CG in terms of sex, age, side of obstruction, or preoperative APD (p > 0.05) (Table 1 ). Table 1 Comparison of Basic Information Between the Two Groups Group Number of Cases Gender (n) Age (months) Side (n) Preoperative Renal Pelvis APD (mm) Male Female Left Right CG 57 51 6 68.0(10.7,105.0) 45 12 28.0(20.0,39.5) MG 63 52 11 65.0(19.0,102.0) 55 8 25.0(20.0,37.0) x² 1.183 1.504 P-value 0.277 0.603 0.220 0.774 2.2 Comparison of surgical time, intraoperative blood loss, postoperative haematuria duration, postoperative hospital stay, and D‒J tube blockage rate Compared with the CG, the MG had significantly shorter surgical times, less intraoperative blood loss, shorter postoperative hospital stays, and shorter postoperative haematuria durations (P < 0.05). Four children in both groups developed lumbar pain, fever, and reduced urination 2–3 days postoperatively. Ultrasound revealed hypoechoic areas in the renal pelvis, indicating D‒J tube blockage. In the MG, one case of D-J tube blockage occurred, with a rate of 1.59% (1/63), whereas in the CG, three cases occurred, with a rate of 12.28% (7/57); significant difference was found between the groups (P < 0.05) (Table 2 ). We replaced the blocked D‒J tubes with F6 small gastric tubes, and after exchange, three children exhibited smooth urination, and the clinical signs resolved. The small gastric tubes were removed before discharge, and follow-up ultrasound revealed improved renal pelvis separation with no significant discomfort. Table 2 Comparison of intraoperative and postoperative data of different surgical methods in children with hydronephrosis Group Surgical Time [M(Q1,Q3),min] Intraoperative Blood Loss [M(Q1,Q3),ml] Postoperative Hospital Stay [M(Q1,Q3),d] Postoperative Hematuria Duration[M(Q1,Q3),d] Postoperative D-J tube blockage(n) CG(n = 57) 100.0(75.0,130.0) 10.0(5.0,17.5) 7.0(6.0,9.5) 3.0(2.0,5.0) 7 MG(n = 63) 85.0.0(75.0,95.0) 6.0(5.0,10.0) 5.0(4.0,5.0) 3.0(1.0,4.0) 1 P-value 0.005 0.022 0.000 0.036 0.048 2.3 Follow-up comparison between groups All 120 patients were followed up, with a mean follow-up duration of 7.0 ± 5.5 months. The postoperative renal pelvis anterior‒posterior diameter (APD) was 15.0 (range: 10.0, 21.0) mm in the MG and 12.0 (range: 8.0, 17.0) mm in the CG. No significant difference was found between the groups (p = 0.114, >0.05). One year after surgery, one patient in each group experienced abdominal pain. Imaging revealed reobstruction, and both patients underwent reoperation with good recovery. The reoperation rate was 1.59% (1/63) in the MG and 1.75% (1/57) in the CG. The success rate was 98.41% (62/63) for the MG and 98.25% (56/57) for the CG, with no significant difference between the two groups (p = 0.99, >0.05) (Table 3 ). Table 3 Comparison of follow-up effects between the two groups Group Postoperative Renal Pelvis APD/[M(Q1,Q3),cm] Surgical Success Rate (%) Reoperation Rate (%) CG 15.0(10.0,21.0) 98.25 1.75 MG 12.0(8.0,17.0) 98.41 1.59 P-value 0.114 0.99 0.99 Discussion Advances in surgical instruments and suturing techniques have made laparoscopic surgery more accepted for paediatric UPJO, even in infants under 3 months of age【5】. Miniaturized tools such as microlaparoscopes have been introduced to reduce surgical trauma and pain. Tan【6】 reported the first paediatric LP cases in which needle-puncture instruments were used, and Dubeux【7】 performed mini-laparoscopic surgery with 3.5 mm instruments in 32 patients, with results similar to those of standard procedures. Fiori 【8】 reported similar findings. These results suggest that reducing the renal pelvis incision size, beyond cosmetic benefits, may significantly improve perioperative outcomes for paediatric patients. In conventional LP, the renal pelvis anastomosis is usually 3.0 cm or greater to ensure smooth urine drainage. However, this can lead to a larger incision, longer suturing time, and increased risk of bleeding. To address this, we innovatively limited the renal pelvis incision to 1.0–1.5 cm. Additionally, we modified the suturing sequence of the renal pelvis-ureteric anastomosis. For the posterior wall, we started suturing approximately 1 needle above the lowest point of the renal pelvis–ureteric junction rather than at the conventional lowest point. After completing the posterior wall anastomosis and placing the double-J stent, we fine-tuned the suture at the lowest point and completed the anterior wall anastomosis. This adjustment reduces repeated clamping and tension at the lowest point, minimizing direct damage. Through clinical practice, we found that starting the first stitch at the lowest point increases the distance between the anastomosis points, increasing suture tension and the risk of dehiscence or poor anastomosis. Delaying the lowest point anastomosis until after completing the posterior wall reduces tension and shortens the distance, whereas the double-J stent provides internal support, ensuring clear visibility and precise suturing of the ureteric orifice. Postoperative data confirmed that the improvement in hydronephrosis and complication rates in the MG was similar to that in the CG but that the former had significant advantages in terms of surgical time, intraoperative blood loss, postoperative haematuria duration, and hospital stay. Previous studies【9】reported a 7.7% complication rate, mainly due to blood clots, D‒J tube blockage, or urine leakage. In this study, the complication rate was 1.59%, suggesting that a minimal incision and modified suturing reduced tissue damage and complications such as bleeding and D‒J tube blockage, leading to faster recovery. In contrast, conventional laparoscopic surgery requires more suturing due to the larger incision, increasing the risk of urine leakage and D-J tube blockage. Pathological studies【10】show that the infant urothelium has more elastic tissue, with the obstructed urothelium containing more elastin. This increases the difficulty of suturing in paediatric LPs, especially in the ureter and renal pelvis. Prolonged laparoscopic surgery and pneumoperitoneum increase the risk of complications【11】. A minimal renal pelvis incision shortens the suturing time, reduces anastomotic tension, and prevents scarring and restenosis. In infants under one year of age, adapting minimally invasive techniques to their smaller anatomy is challenging. A minimal incision provides more space, improving surgical precision, reducing accidental injury, and lowering intraoperative risks. Although postoperative restenosis is rare, reoperation is more difficult than initial surgery【12】. Our improved approach follows the "no-touch technique," which minimizes direct contact with the ureter during anastomosis. For example, Radfar MH【13】partially cuts the ureter, leaving it attached to the renal pelvis to reduce handling. This method preserves the ureteral blood supply, reduces inflammation, speeds recovery, and decreases scarring and stenosis【14,15】. By avoiding the lowest point of the incision for the first suture, we minimize tension and damage. Suspension sutures keep the incision stable, ensuring optimal no-touch anastomosis. Larger incisions often require more clamping, increasing trauma and complications. In summary, optimizing the anastomotic strategy improves tissue protection, surgical safety, and long-term outcomes. Postoperative D‒J tube blockage is a key factor affecting surgical outcomes, with symptoms such as vomiting, fever, and increased abdominal drainage, which can reduce both surgical success and patient satisfaction【16】. Although blockage is rare, it can decrease parental satisfaction and trust in the surgeon, complicating management. Reducing blockage rates is crucial. Minimal renal pelvis incisions and optimized suturing can reduce bleeding and the risk of blockage. Our study revealed a 1.59% blockage rate in the modified group compared with 12.28% in the control group, this difference was statistically significant. For eight patients who underwent blockage, we used cystoscopy to remove the D‒J tube, inserted an F6 gastric tube for renal pelvis drainage, and flushed the tube if needed. We do not recommend replacing the D‒J tube, as it poses a risk of recurrent blockage【17】. The gastric tube drainage option avoids additional anaesthesia and surgery, reducing patient burden and improving patient satisfaction. Devrim【18】 noted that replacing the D‒J tube increases complexity and the risk of blockage. Thus, we recommend gastric tube drainage as the preferred method, as it is simpler, less prone to complications, and better tolerated by patients. This study has several limitations. As a single-centre retrospective analysis with a minimal sample size and limited follow-up, selection bias may exist, and the findings may not be widely applicable. Larger, multicentre, prospective studies with longer follow-up periods are needed to confirm the long-term benefits of the modified technique. Additionally, the technique requires advanced surgical skills, making it unsuitable for all paediatric UPJO patients. The effect of incision size on outcomes may be overestimated, as factors such as patient selection and surgeon experience also play a role. In conclusion, while the modified laparoscopic technique shows promise, further research is needed to refine and evaluate its broader applicability. Conclusion Our modified laparoscopic suturing technique with a Minimal renal pelvis incision provides a better option for paediatric UPJO surgery, reducing suturing difficulty and D-J tube blockage, leading to improved outcomes and quicker recovery. Abbreviations UPJO ureteropelvic junction obstruction LP laparoscopic pyeloplasty MG Modified Group CG control group APD anterior-posterior diameters Declarations Data availability Data that support the findings presented in this manuscript will be made available upon reasonable request. Acknowledgements We would like to thank the staff members of the Department of Pediatrics at our hospital for their technical support. We would like to thank Springer Nature for English language editing. Funding The research received funding from the National Natural Science Foundation of China (82000643), and the Scientific Research Project of Jiangsu Health Commission (M2021007). Author information Authors and Affiliations Department of Urology, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing 210008, Jiangsu, China Jiaqi Dong, Yiming Yuan, Jiajing Qiu, Xiaoyu Li, Xiaojiang Zhu,Jun Wang, Yunfei Guo, Yongji Deng, Liqu Huang Yancheng Maternal and Child Health Care Hospital Affiliated to Yangzhou University,Yancheng 224000, Jiangsu, China Lizhong Shi, Tonglie Ni Authors' contributions JQD participated in the design of this study, and they performed the analysis.YMY and JJQ carried out the study and collected important background information.LQH and YJD operated.LQH and TLN drafted the manuscript.YFG and LZS directed the research and gave us a lot of very good advices. All authors read and approved the final manuscript. Ethics declarations Ethics approval and consent to participate This retrospective study was conducted in accordance with the Declaration of Helsinki and was approved by the Medical Ethics Committee of Children's Hospital of Nanjing Medical University, Ethics No. 202503017-1.Informed consent was waived by the committee due to the retrospective design and use of anonymized medical records, in accordance with China’s Ethical Guidelines for Medical Research Involving Human Subjects (National Health Commission, 2016). For participants under 16 years of age, parental/guardian consent was waived as no direct contact occurred and all data were de-identified prior to analysis. All patient data were handled in compliance with relevant data protection and privacy regulations（Clinical trial is not applicable）. Consent for publication Not applicable. Competing interests The authors declare no competing interests. References Cascini V, Lauriti G, Di Renzo D, Miscia ME, Lisi G. Ureteropelvic junction obstruction in infants: Open or minimally invasive surgery? A systematic review and meta-analysis. Front Pediatr. 2022 Nov 23;10:1052440. doi: 10.3389/fped.2022.1052440. Alqarni NH, Alyami FA, Alshayie MA, Abduldaem AM, Sultan M, Almaiman SS, Alsufyani HM, Abunohaiah IS. Minimally invasive versus open pyeloplasty in pediatric population: Comparative retrospective study in tertiary centre. Urol Ann. 2024 Jul-Sep;16(3):215-217. doi: 10.4103/ua.ua_101_23. Gao B, Farhat W, Zu'bi F, Chua M, Shiff M, Al-Kutbi R, Pokarowski M, Ming J, Kim J, Dos Santos J, Koyle M. Comparative analysis of suturing technique in pediatric pyeloplasty on surgical outcomes. Pediatr Surg Int. 2021 Nov;37(11):1633-1637. doi: 10.1007/s00383-021-04960-9. Passoni NM, Peters CA. Managing Ureteropelvic Junction Obstruction in the Young Infant. Front Pediatr. 2020 May 27;8:242. doi: 10.3389/fped.2020.00242. Tan HL. Laparoscopic Anderson-Hynes dismembered pyeloplasty in children using needlescopic instrumentation. Urol Clin North Am. 2001 Feb;28(1):43-51, viii. doi: 10.1016/s0094-0143(01)80006-9. Dubeux VT, Carrerette F, Peçanha G, Medeiros L, Gabrich P, Milfont J, Damião R. Minilaparoscopy in urology: initial results after 32 cases. World J Urol. 2016 Jan;34(1):137-42. doi: 10.1007/s00345-015-1602-8. Fiori C, Morra I, Bertolo R, Mele F, Chiarissi ML, Porpiglia F. Standard vs mini-laparoscopic pyeloplasty: perioperative outcomes and cosmetic results. BJU Int. 2013 Mar;111(3 Pt B):E121-6. doi: 10.1111/j.1464-410X.2012.11376.x. Silay MS, Spinoit AF, Undre S, Fiala V, Tandogdu Z, Garmanova T, Guttilla A, Sancaktutar AA, Haid B, Waldert M, Goyal A, Serefoglu EC, Baldassarre E, Manzoni G, Radford A, Subramaniam R, Cherian A, Hoebeke P, Jacobs M, Rocco B, Yuriy R, Zattoni F, Kocvara R, Koh CJ. Global minimally invasive pyeloplasty study in children: Results from the Pediatric Urology Expert Group of the European Association of Urology Young Academic Urologists working party. J Pediatr Urol. 2016 Aug;12(4):229.e1-7. doi: 10.1016/j.jpurol.2016.04.007. Sokolis DP. Alterations with age in the biomechanical behavior of human ureteral wall: Microstructure-based modeling. J Biomech. 2020 Aug 26;109:109940. doi: 10.1016/j.jbiomech.2020.109940. Jackson TD, Wannares JJ, Lancaster RT, Rattner DW, Hutter MM. Does speed matter? The impact of operative time on outcome in laparoscopic surgery. Surg Endosc. 2011 Jul;25(7):2288-95. doi: 10.1007/s00464-010-1550-8. Boysen WR, Gundeti MS. Robot-assisted laparoscopic pyeloplasty in the pediatric population: a review of technique, outcomes, complications, and special considerations in infants. Pediatr Surg Int. 2017 Sep;33(9):925-935. doi: 10.1007/s00383-017-4082-7. Hong P, Cai Y, Li Z, Fan S, Yang K, Hao H, He Q, Li X, Zhou L. Modified Laparoscopic Partial Ureterectomy for Adult Ureteral Fibroepithelial Polyp: Technique and Initial Experience. Urol Int. 2019;102(1):13-19. doi: 10.1159/000494804. Radfar MH, Afyouni A, Shakiba B, Hamedanchi S, Zare A. A New Touchless Technique for Suturing in Transperitoneal Laparoscopic Pyeloplasty. J Laparoendosc Adv Surg Tech A. 2019 Apr;29(4):519-522. doi: 10.1089/lap.2018.0635. Swords KA, Rodriguez AR, Rich MA, Swana HS. A novel “no-touch” robot-assisted laparoscopic technique facilitates ureteral reconstructive surgery. Int Braz J Urol. 2011 May-Jun;37(3):419; discussion 420. doi: 10.1590/s1677-55382011000300033. Geavlete P, Georgescu D, Mulțescu R, Stanescu F, Cozma C, Geavlete B. Ureteral stent complications - experience on 50,000 procedures. J Med Life. 2021 Nov-Dec;14(6):769-775. doi: 10.25122/jml-2021-0352. Divya G, Kundal VK, Shah S, Debnath PR, Meena AK, Sen A. Complications and Management of Retained Double-J Stents in Children During the Coronavirus Disease-2019 Pandemic. J Indian Assoc Pediatr Surg. 2022 Nov-Dec;27(6):735-740. doi: 10.4103/jiaps.jiaps_67_22. Akıncı D, Ünal E, Çiftçi TT, Özkan OŞ, Akhan O. Management of single double-J stent failure in malignant ureteral obstruction: tandem ureteral stenting with less frequent stent exchange. Diagn Interv Radiol. 2023 Mar 29;29(2):312-317. doi: 10.5152/dir.2022.21638. Gao B, Farhat W, Zu'bi F, Chua M, Shiff M, Al-Kutbi R, Pokarowski M, Ming J, Kim J, Dos Santos J, Koyle M. Comparative analysis of suturing technique in pediatric pyeloplasty on surgical outcomes. Pediatr Surg Int. 2021 Nov;37(11):1633-1637. doi: 10.1007/s00383-021-04960-9. Additional Declarations No competing interests reported. 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Huang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyklEQVRIiWNgGAWjYBACAzBZIMHAwN7Y+PAD8VoMgFp4DjcbS5CgBYgl0tsEeIjRYi6R/OzhFwML2Q03H7YxSDDYyek2ENBiOSPN3FjGQMJ4w+3EtgcFDMnGZgcIOexGgpm0hIFE4szZie1ALx1I3EZYS/o3iJaZB9skeIjTkmMm+QGopV+CkVgtZ96USQMD2bifJxEYyAbE+OV4+jbJHxV1sm3sxx8+/FBhJ0dQCwgwA6ODsQFiAhHKQYDxB1zLKBgFo2AUjAIsAADs+UCdU+PZKwAAAABJRU5ErkJggg==","orcid":"","institution":"Children's Hospital of Nanjing Medical University","correspondingAuthor":true,"prefix":"","firstName":"Liqu","middleName":"","lastName":"Huang","suffix":""}],"badges":[],"createdAt":"2025-09-15 16:23:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7622736/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7622736/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":94547065,"identity":"d49eeaa5-a651-4221-b935-554c68cf5c14","added_by":"auto","created_at":"2025-10-28 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17:42:00","extension":"xml","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":75788,"visible":true,"origin":"","legend":"","description":"","filename":"51777fc494734854a3221dfaa0ed92151structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7622736/v1/192107a5ab6d9318522a765e.xml"},{"id":94546760,"identity":"79f0888f-4e9c-426c-a566-d969c80effa2","added_by":"auto","created_at":"2025-10-28 17:40:51","extension":"html","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":87255,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7622736/v1/987e700cd3225a507c403ddb.html"},{"id":94546854,"identity":"d2f9c3b4-b975-4522-ba01-7ae4fadbeff1","added_by":"auto","created_at":"2025-10-28 17:41:12","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":370370,"visible":true,"origin":"","legend":"\u003cp\u003eA: A 1.0-1.5 cm incision in the renal pelvis for anastomosis.\u003c/p\u003e\n\u003cp\u003eB: The first suture is placed one needle's distance above the lowest point of the renal pelvis and ureteric incisions for suturing the posterior wall.\u003c/p\u003e\n\u003cp\u003eC: The posterior wall of the renal pelvis and ureter is completely sutured.\u003c/p\u003e\n\u003cp\u003eD: After placing the D-J tube, the lowest point of the renal pelvis and ureteric junction is sutured (a, b), and suturing of the anterior wall begins.\u003c/p\u003e\n\u003cp\u003eE: The renal pelvis and ureter anastomosis is completed.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7622736/v1/5440a8a060c5178842d2a48e.png"},{"id":94547176,"identity":"ffa031f0-55b1-491a-9d8d-4ce29aeef396","added_by":"auto","created_at":"2025-10-28 17:42:14","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":471524,"visible":true,"origin":"","legend":"\u003cp\u003eThe renal pelvis incision size in the MG is approximately 1.0 cm.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7622736/v1/1b615bb6446fae8ee8c87b6c.png"},{"id":94546717,"identity":"832759e4-dc63-44f6-b577-d95a3e4392c9","added_by":"auto","created_at":"2025-10-28 17:40:28","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":609088,"visible":true,"origin":"","legend":"\u003cp\u003eThe renal pelvis incision size in the CG is approximately 3.0 cm.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7622736/v1/af24284c17b97e4b78f79eca.png"},{"id":103500706,"identity":"eb23087a-6788-496d-b3c1-f26d49b368e2","added_by":"auto","created_at":"2026-02-26 12:12:06","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3131447,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7622736/v1/5eba9ba3-52c0-4168-986a-a70b289b4cab.pdf"},{"id":94546618,"identity":"32d10240-9749-4efa-b5df-5e5935d2734f","added_by":"auto","created_at":"2025-10-28 17:39:58","extension":"xlsx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":21720,"visible":true,"origin":"","legend":"","description":"","filename":"file.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7622736/v1/d759998d23a266503c2f1f81.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparative Study of a Modified Suture Technique with a Minimal Renal Pelvis Incision in Paediatric Hydronephrosis Treatment","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePaediatric congenital hydronephrosis, typically identified through prenatal ultrasound (US) screening or postnatal ultrasound when symptoms appear, is characterized by dilation of the renal collecting system, with ureteropelvic junction obstruction (UPJO) being the most common underlying cause. Since Schuessler et al. first introduced laparoscopic pyeloplasty (LP) in 1993【1】, this technique has gained widespread clinical adoption and has gradually replaced open surgery as the preferred treatment for paediatric UPJO. LP not only offers comparable long-term success rates to open surgery but also provides advantages such as improved cosmetic outcomes, shorter hospital stays, and faster recovery times, especially in developing countries where robotic surgery is less prevalent【2, 3】.\u003c/p\u003e\u003cp\u003eDespite its advantages, LP still presents technical challenges, especially in achieving safe, tension-free renal pelvis-ureter anastomosis, which requires advanced suturing skills. The technique for suturing the lowest point of the renal pelvis and ureter directly impacts treatment outcomes for patients and the prognosis of hydronephrosis, requiring high surgical expertise【4】. This study innovatively improves the suturing technique and reduces the renal pelvis incision size, enhancing surgical outcomes, shortening operative time, and reducing D-J tube blockage. To our knowledge, this is the first study to examine the impact of renal pelvis incision size and modified suturing technique. This comparison between LP with a minimal renal pelvis incision and standard LP offers valuable insights for managing paediatric UPJO.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e1.1 General Information\u003c/h2\u003e\u003cp\u003eA retrospective analysis was conducted on the clinical data of 120 children with congenital hydronephrosis treated surgically in the Department of Urology at the Children's Hospital of Nanjing Medical University, from January 2022 to June 2024. All of them underwent urologic ultrasound, magnetic resonance urography (MRU), and voiding cystourethrography (VCUG) preoperatively, and some of them underwent renal scintigraphy. The 63 children who underwent LP with a small renal pelvis incision (incision\u0026thinsp;\u0026le;\u0026thinsp;1.5 cm) were designated as the SIG, while the 57 children who underwent standard LP (incision\u0026thinsp;\u0026gt;\u0026thinsp;1.5 cm) were designated as the CG. The guardians of the patients signed an informed consent for the surgery before the operation, and the study was approved by the Medical Ethics Committee of Children's Hospital of Nanjing Medical University, Ethics No. 202503017-1.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e1.2 Inclusion and Exclusion Criteria\u003c/h2\u003e\u003cp\u003eThe inclusion criteria were as follows: ① symptomatic obstruction (costovertebral pain, urinary tract infection). ② Impaired renal function (renal function\u0026thinsp;\u0026lt;\u0026thinsp;40%). ③ A\u0026thinsp;\u0026gt;\u0026thinsp;10% decrease in renal function during follow-up. ④ Ultrasound showing an increased anterior‒posterior diameter of the renal pelvis. ⑤ SFU grade III or IV dilation. ⑥ Children aged 0\u0026ndash;16 years. ⑦ Patients were randomly allocated to both groups.\u003c/p\u003e\u003cp\u003eThe exclusion criteria were as follows: ① other causes of hydronephrosis, such as urinary tract stones, posterior urethral valves, or distal ureteral stenosis; and ② significant underlying diseases or other surgical comorbidities. ③ Bilateral hydronephrosis. ④ Failure to attend regular follow-up appointments.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e1.3 Methods\u003c/h2\u003e\u003cp\u003e\u003cb\u003eSurgical procedure in the MG\u003c/b\u003e:\u003c/p\u003e\u003cp\u003eAfter anaesthesia, a urinary catheter was inserted, and the patient was positioned laterally. The skin was disinfected, and sterile drapes were applied. A 5 mm trocar was inserted at the umbilicus, with two more screws placed above and below. The posterior peritoneum was opened with an ultrasonic scalpel. The renal pelvis and ureteric junction were freed, and two suspension sutures were placed for support. The renal pelvis\u0026ndash;ureteric junction was resected, and a 1.0-1.5 cm segment of the renal pelvis was resected for anastomosis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). A longitudinal incision was made on the lateral wall of the ureter. Rather than starting the anastomosis at the lowest point of the renal pelvis and ureteric junction, the first suture was placed one needle's distance above the lowest point of the renal pelvis and ureteric incision (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). The posterior wall of the renal pelvis and ureter was continuously sutured (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC), and a D‒J tube was inserted. The lowest point of the renal pelvis and ureteric junction was sutured (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eD, a, b). The anterior wall of the renal pelvis and ureter was then continuously sutured (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eE). After completion, the renal pelvis-ureter junction was positioned at the lowest point without any torsion. The trocar was withdrawn, and the incision was sutured.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSurgical procedure in the CG\u003c/b\u003e:\u003c/p\u003e\u003cp\u003eAfter anaesthesia, positioning, trocar insertion, and exposure of the renal pelvis and ureteric junction were similar to those of the MG. Both were freed, and two suspension sutures were placed for support. The renal pelvis\u0026ndash;ureteric junction was resected, and a 3 cm incision was made on the renal pelvis for anastomosis (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The anastomosis started from the lowest point of the renal pelvis, and a ureteric incision was made. Continuous or interrupted sutures were used to repair the posterior wall of the renal pelvis and ureter, and a D‒J tube was placed. Continuous or interrupted sutures were used to repair the anterior wall of the renal pelvis and ureter. After suturing, the renal pelvis-ureter junction was positioned at the lowest point without any torsion. The incision was sutured after the trocar was withdrawn.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e1.4 Postoperative Management\u003c/h2\u003e\u003cp\u003ePostoperative observation included monitoring for symptoms such as abdominal distension, lumbar pain, haematuria, and urinary difficulties. A urinary catheter was typically retained for 3\u0026ndash;5 days before removal. Routine prophylactic antibiotics were administered for 2‒3 days. One month after discharge, the D‒J tube was removed via cystoscopy.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e1.5 Outcome measures and efficacy evaluation\u003c/h2\u003e\u003cp\u003eSurgical time (minutes), intraoperative blood loss (millilitres), postoperative haematuria duration (days), and postoperative hospital stay were compared between the two groups. Additionally, the success rate of the procedure and occurrence of postoperative complications (such as urinary leakage, incision infection, fever, and D‒J tube blockage) were assessed. All patients underwent ultrasound follow-up 2 months after surgery, with subsequent follow-ups every 6 months. Surgical success criteria included clinical symptom relief, stable or improved renal function, and improvement in the anterior‒posterior diameter of the renal pelvis.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e1.6 Statistical methods\u003c/h2\u003e\u003cp\u003eThe data were analysed using SPSS\u003csup\u003e\u0026reg;\u003c/sup\u003e 25.0. Categorical variables are expressed as numbers and were compared using the Chi-square test or Fisher\u0026rsquo;s exact test, where appropriate. Data between groups were compared using Student's t test or the Chi-square test. Nonnormally distributed data are expressed as median ranges and were compared using the Mann‒Whitney test. All the statistical tests were two-sided, with the significance level set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e2.1 General information\u003c/h2\u003e\u003cp\u003eThis study included 120 children, consisting of 103 males and 17 females, with a median age of 68.0 months (range: 15.0\u0026ndash;102.8 months). Among them, 100 cases were left-sided, and 20 were right-sided. Forty-six patients were prenatally diagnosed with asymptomatic hydronephrosis, whereas 74 patients had symptomatic hydronephrosis. The MG included 63 children, with an age range of 1.9\u0026ndash;174 months and an average age of 67.75\u0026thinsp;\u0026plusmn;\u0026thinsp;48.97 months; 52 males and 11 females were included. The CG consisted of 57 children, with ages ranging from 1.4\u0026ndash;165 months and an average age of 64.48\u0026thinsp;\u0026plusmn;\u0026thinsp;52.19 months; 51 males and 6 females were included. There were no significant differences between the MG and CG in terms of sex, age, side of obstruction, or preoperative APD (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of Basic Information Between the Two Groups\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eGroup\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eNumber of Cases\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003eGender (n)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eAge (months)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003eSide (n)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003ePreoperative Renal Pelvis APD (mm)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLeft\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eRight\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCG\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e57\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e68.0(10.7,105.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e45\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003e28.0(20.0,39.5)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMG\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e63\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e52\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e11\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e65.0(19.0,102.0)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e55\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cb\u003e8\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u003cb\u003e25.0(20.0,37.0)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ex\u0026sup2;\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e\u003cb\u003e1.183\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003e\u003cb\u003e1.504\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eP-value\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e\u003cb\u003e0.277\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.603\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e\u003cp\u003e\u003cb\u003e0.220\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u003cb\u003e0.774\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e2.2 Comparison of surgical time, intraoperative blood loss, postoperative haematuria duration, postoperative hospital stay, and D‒J tube blockage rate\u003c/b\u003e\u003c/p\u003e\u003cp\u003eCompared with the CG, the MG had significantly shorter surgical times, less intraoperative blood loss, shorter postoperative hospital stays, and shorter postoperative haematuria durations (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Four children in both groups developed lumbar pain, fever, and reduced urination 2\u0026ndash;3 days postoperatively. Ultrasound revealed hypoechoic areas in the renal pelvis, indicating D‒J tube blockage. In the MG, one case of D-J tube blockage occurred, with a rate of 1.59% (1/63), whereas in the CG, three cases occurred, with a rate of 12.28% (7/57); significant difference was found between the groups (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). We replaced the blocked D‒J tubes with F6 small gastric tubes, and after exchange, three children exhibited smooth urination, and the clinical signs resolved. The small gastric tubes were removed before discharge, and follow-up ultrasound revealed improved renal pelvis separation with no significant discomfort.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of intraoperative and postoperative data of different surgical methods in children with hydronephrosis\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"6\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroup\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSurgical Time [M(Q1,Q3),min]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eIntraoperative Blood Loss [M(Q1,Q3),ml]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePostoperative Hospital Stay [M(Q1,Q3),d]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePostoperative Hematuria Duration[M(Q1,Q3),d]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePostoperative D-J tube blockage(n)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCG(n\u0026thinsp;=\u0026thinsp;57)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e100.0(75.0,130.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10.0(5.0,17.5)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7.0(6.0,9.5)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.0(2.0,5.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMG(n\u0026thinsp;=\u0026thinsp;63)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e85.0.0(75.0,95.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6.0(5.0,10.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5.0(4.0,5.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.0(1.0,4.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eP-value\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e0.005\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e0.022\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e0.000\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e0.036\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e0.048\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Follow-up comparison between groups\u003c/h2\u003e\u003cp\u003eAll 120 patients were followed up, with a mean follow-up duration of 7.0\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5 months. The postoperative renal pelvis anterior‒posterior diameter (APD) was 15.0 (range: 10.0, 21.0) mm in the MG and 12.0 (range: 8.0, 17.0) mm in the CG. No significant difference was found between the groups (p\u0026thinsp;=\u0026thinsp;0.114, \u0026gt;0.05). One year after surgery, one patient in each group experienced abdominal pain. Imaging revealed reobstruction, and both patients underwent reoperation with good recovery. The reoperation rate was 1.59% (1/63) in the MG and 1.75% (1/57) in the CG. The success rate was 98.41% (62/63) for the MG and 98.25% (56/57) for the CG, with no significant difference between the two groups (p\u0026thinsp;=\u0026thinsp;0.99, \u0026gt;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of follow-up effects between the two groups\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGroup\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePostoperative Renal Pelvis APD/[M(Q1,Q3),cm]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSurgical Success Rate (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eReoperation Rate (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCG\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15.0(10.0,21.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e98.25\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.75\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMG\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12.0(8.0,17.0)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e98.41\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.59\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eP-value\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e0.114\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e0.99\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e0.99\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eAdvances in surgical instruments and suturing techniques have made laparoscopic surgery more accepted for paediatric UPJO, even in infants under 3 months of age【5】. Miniaturized tools such as microlaparoscopes have been introduced to reduce surgical trauma and pain. Tan【6】 reported the first paediatric LP cases in which needle-puncture instruments were used, and Dubeux【7】 performed mini-laparoscopic surgery with 3.5 mm instruments in 32 patients, with results similar to those of standard procedures. Fiori 【8】 reported similar findings. These results suggest that reducing the renal pelvis incision size, beyond cosmetic benefits, may significantly improve perioperative outcomes for paediatric patients. In conventional LP, the renal pelvis anastomosis is usually 3.0 cm or greater to ensure smooth urine drainage. However, this can lead to a larger incision, longer suturing time, and increased risk of bleeding. To address this, we innovatively limited the renal pelvis incision to 1.0\u0026ndash;1.5 cm. Additionally, we modified the suturing sequence of the renal pelvis-ureteric anastomosis. For the posterior wall, we started suturing approximately 1 needle above the lowest point of the renal pelvis\u0026ndash;ureteric junction rather than at the conventional lowest point. After completing the posterior wall anastomosis and placing the double-J stent, we fine-tuned the suture at the lowest point and completed the anterior wall anastomosis. This adjustment reduces repeated clamping and tension at the lowest point, minimizing direct damage. Through clinical practice, we found that starting the first stitch at the lowest point increases the distance between the anastomosis points, increasing suture tension and the risk of dehiscence or poor anastomosis. Delaying the lowest point anastomosis until after completing the posterior wall reduces tension and shortens the distance, whereas the double-J stent provides internal support, ensuring clear visibility and precise suturing of the ureteric orifice.\u003c/p\u003e\u003cp\u003ePostoperative data confirmed that the improvement in hydronephrosis and complication rates in the MG was similar to that in the CG but that the former had significant advantages in terms of surgical time, intraoperative blood loss, postoperative haematuria duration, and hospital stay. Previous studies【9】reported a 7.7% complication rate, mainly due to blood clots, D‒J tube blockage, or urine leakage. In this study, the complication rate was 1.59%, suggesting that a minimal incision and modified suturing reduced tissue damage and complications such as bleeding and D‒J tube blockage, leading to faster recovery. In contrast, conventional laparoscopic surgery requires more suturing due to the larger incision, increasing the risk of urine leakage and D-J tube blockage.\u003c/p\u003e\u003cp\u003ePathological studies【10】show that the infant urothelium has more elastic tissue, with the obstructed urothelium containing more elastin. This increases the difficulty of suturing in paediatric LPs, especially in the ureter and renal pelvis. Prolonged laparoscopic surgery and pneumoperitoneum increase the risk of complications【11】. A minimal renal pelvis incision shortens the suturing time, reduces anastomotic tension, and prevents scarring and restenosis. In infants under one year of age, adapting minimally invasive techniques to their smaller anatomy is challenging. A minimal incision provides more space, improving surgical precision, reducing accidental injury, and lowering intraoperative risks. Although postoperative restenosis is rare, reoperation is more difficult than initial surgery【12】. Our improved approach follows the \"no-touch technique,\" which minimizes direct contact with the ureter during anastomosis. For example, Radfar MH【13】partially cuts the ureter, leaving it attached to the renal pelvis to reduce handling. This method preserves the ureteral blood supply, reduces inflammation, speeds recovery, and decreases scarring and stenosis【14,15】. By avoiding the lowest point of the incision for the first suture, we minimize tension and damage. Suspension sutures keep the incision stable, ensuring optimal no-touch anastomosis. Larger incisions often require more clamping, increasing trauma and complications. In summary, optimizing the anastomotic strategy improves tissue protection, surgical safety, and long-term outcomes.\u003c/p\u003e\u003cp\u003ePostoperative D‒J tube blockage is a key factor affecting surgical outcomes, with symptoms such as vomiting, fever, and increased abdominal drainage, which can reduce both surgical success and patient satisfaction【16】. Although blockage is rare, it can decrease parental satisfaction and trust in the surgeon, complicating management. Reducing blockage rates is crucial. Minimal renal pelvis incisions and optimized suturing can reduce bleeding and the risk of blockage. Our study revealed a 1.59% blockage rate in the modified group compared with 12.28% in the control group, this difference was statistically significant. For eight patients who underwent blockage, we used cystoscopy to remove the D‒J tube, inserted an F6 gastric tube for renal pelvis drainage, and flushed the tube if needed. We do not recommend replacing the D‒J tube, as it poses a risk of recurrent blockage【17】. The gastric tube drainage option avoids additional anaesthesia and surgery, reducing patient burden and improving patient satisfaction. Devrim【18】 noted that replacing the D‒J tube increases complexity and the risk of blockage. Thus, we recommend gastric tube drainage as the preferred method, as it is simpler, less prone to complications, and better tolerated by patients.\u003c/p\u003e\u003cp\u003eThis study has several limitations. As a single-centre retrospective analysis with a minimal sample size and limited follow-up, selection bias may exist, and the findings may not be widely applicable. Larger, multicentre, prospective studies with longer follow-up periods are needed to confirm the long-term benefits of the modified technique. Additionally, the technique requires advanced surgical skills, making it unsuitable for all paediatric UPJO patients. The effect of incision size on outcomes may be overestimated, as factors such as patient selection and surgeon experience also play a role. In conclusion, while the modified laparoscopic technique shows promise, further research is needed to refine and evaluate its broader applicability.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eOur modified laparoscopic suturing technique with a Minimal renal pelvis incision provides a better option for paediatric UPJO surgery, reducing suturing difficulty and D-J tube blockage, leading to improved outcomes and quicker recovery.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eUPJO\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eureteropelvic junction obstruction\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eLP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003elaparoscopic pyeloplasty\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eMG\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eModified Group\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCG\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003econtrol group\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eAPD\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eanterior-posterior diameters\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData that support the findings presented in this manuscript will be made available upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank the staff members of the Department of Pediatrics at our hospital for their technical support. We would like to thank Springer Nature for English language editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe research received funding from the National Natural Science Foundation of China (82000643), and the Scientific Research Project of Jiangsu Health Commission (M2021007).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors and Affiliations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDepartment of Urology, Children\u0026apos;s Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing 210008, Jiangsu, China\u003c/p\u003e\n\u003cp\u003eJiaqi Dong, Yiming Yuan, Jiajing Qiu, Xiaoyu Li, Xiaojiang Zhu,Jun Wang, Yunfei Guo, Yongji Deng, Liqu Huang\u003c/p\u003e\n\u003cp\u003eYancheng Maternal and Child Health Care Hospital Affiliated to Yangzhou University,Yancheng 224000, Jiangsu, China\u003c/p\u003e\n\u003cp\u003eLizhong Shi, Tonglie Ni\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJQD participated in the design of this study, and they performed the analysis.YMY and JJQ carried out the study and collected important background information.LQH and YJD operated.LQH and TLN drafted the manuscript.YFG and LZS directed the research and gave us a lot of very good advices. All authors read and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics declarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective study was conducted in accordance with the Declaration of Helsinki and was approved by the Medical Ethics Committee of Children\u0026apos;s Hospital of Nanjing Medical University, Ethics No. 202503017-1.Informed consent was waived by the committee due to the retrospective design and use of anonymized medical records, in accordance with China\u0026rsquo;s Ethical Guidelines for Medical Research Involving Human Subjects (National Health Commission, 2016). For participants under 16 years of age, parental/guardian consent was waived as no direct contact occurred and all data were de-identified prior to analysis. All patient data were handled in compliance with relevant data protection and privacy regulations（Clinical trial is not applicable）.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eCascini V, Lauriti G, Di Renzo D, Miscia ME, Lisi G. Ureteropelvic junction obstruction in infants: Open or minimally invasive surgery? A systematic review and meta-analysis. Front Pediatr. 2022 Nov 23;10:1052440. doi: 10.3389/fped.2022.1052440.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eAlqarni NH, Alyami FA, Alshayie MA, Abduldaem AM, Sultan M, Almaiman SS, Alsufyani HM, Abunohaiah IS. Minimally invasive versus open pyeloplasty in pediatric population: Comparative retrospective study in tertiary centre. Urol Ann. 2024 Jul-Sep;16(3):215-217. doi: 10.4103/ua.ua_101_23.\u003c/li\u003e\n \u003cli\u003eGao B, Farhat W, Zu\u0026apos;bi F, Chua M, Shiff M, Al-Kutbi R, Pokarowski M, Ming J, Kim J, Dos Santos J, Koyle M. Comparative analysis of suturing technique in pediatric pyeloplasty on surgical outcomes. Pediatr Surg Int. 2021 Nov;37(11):1633-1637. doi: 10.1007/s00383-021-04960-9.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePassoni NM, Peters CA. Managing Ureteropelvic Junction Obstruction in the Young Infant. Front Pediatr. 2020 May 27;8:242. doi: 10.3389/fped.2020.00242.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eTan HL. Laparoscopic Anderson-Hynes dismembered pyeloplasty in children using needlescopic instrumentation. Urol Clin North Am. 2001 Feb;28(1):43-51, viii. doi: 10.1016/s0094-0143(01)80006-9.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eDubeux VT, Carrerette F, Pe\u0026ccedil;anha G, Medeiros L, Gabrich P, Milfont J, Dami\u0026atilde;o R. Minilaparoscopy in urology: initial results after 32 cases. World J Urol. 2016 Jan;34(1):137-42. doi: 10.1007/s00345-015-1602-8.\u003c/li\u003e\n \u003cli\u003eFiori C, Morra I, Bertolo R, Mele F, Chiarissi ML, Porpiglia F. Standard vs mini-laparoscopic pyeloplasty: perioperative outcomes and cosmetic results. BJU Int. 2013 Mar;111(3 Pt B):E121-6. doi: 10.1111/j.1464-410X.2012.11376.x.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSilay MS, Spinoit AF, Undre S, Fiala V, Tandogdu Z, Garmanova T, Guttilla A, Sancaktutar AA, Haid B, Waldert M, Goyal A, Serefoglu EC, Baldassarre E, Manzoni G, Radford A, Subramaniam R, Cherian A, Hoebeke P, Jacobs M, Rocco B, Yuriy R, Zattoni F, Kocvara R, Koh CJ. Global minimally invasive pyeloplasty study in children: Results from the Pediatric Urology Expert Group of the European Association of Urology Young Academic Urologists working party. J Pediatr Urol. 2016 Aug;12(4):229.e1-7. doi: 10.1016/j.jpurol.2016.04.007.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSokolis DP. Alterations with age in the biomechanical behavior of human ureteral wall: Microstructure-based modeling. J Biomech. 2020 Aug 26;109:109940. doi: 10.1016/j.jbiomech.2020.109940.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eJackson TD, Wannares JJ, Lancaster RT, Rattner DW, Hutter MM. Does speed matter? The impact of operative time on outcome in laparoscopic surgery. Surg Endosc. 2011 Jul;25(7):2288-95. doi: 10.1007/s00464-010-1550-8.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eBoysen WR, Gundeti MS. Robot-assisted laparoscopic pyeloplasty in the pediatric population: a review of technique, outcomes, complications, and special considerations in infants. Pediatr Surg Int. 2017 Sep;33(9):925-935. doi: 10.1007/s00383-017-4082-7.\u003c/li\u003e\n \u003cli\u003eHong P, Cai Y, Li Z, Fan S, Yang K, Hao H, He Q, Li X, Zhou L. Modified Laparoscopic Partial Ureterectomy for Adult Ureteral Fibroepithelial Polyp: Technique and Initial Experience. Urol Int. 2019;102(1):13-19. doi: 10.1159/000494804.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eRadfar MH, Afyouni A, Shakiba B, Hamedanchi S, Zare A. A New Touchless Technique for Suturing in Transperitoneal Laparoscopic Pyeloplasty. J Laparoendosc Adv Surg Tech A. 2019 Apr;29(4):519-522. doi: 10.1089/lap.2018.0635.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSwords KA, Rodriguez AR, Rich MA, Swana HS. A novel \u0026ldquo;no-touch\u0026rdquo; robot-assisted laparoscopic technique facilitates ureteral reconstructive surgery. Int Braz J Urol. 2011 May-Jun;37(3):419; discussion 420. doi: 10.1590/s1677-55382011000300033.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eGeavlete P, Georgescu D, Mulțescu R, Stanescu F, Cozma C, Geavlete B. Ureteral stent complications - experience on 50,000 procedures. J Med Life. 2021 Nov-Dec;14(6):769-775. doi: 10.25122/jml-2021-0352.\u003c/li\u003e\n \u003cli\u003eDivya G, Kundal VK, Shah S, Debnath PR, Meena AK, Sen A. Complications and Management of Retained Double-J Stents in Children During the Coronavirus Disease-2019 Pandemic. J Indian Assoc Pediatr Surg. 2022 Nov-Dec;27(6):735-740. doi: 10.4103/jiaps.jiaps_67_22.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eAkıncı D, \u0026Uuml;nal E, \u0026Ccedil;ift\u0026ccedil;i TT, \u0026Ouml;zkan OŞ, Akhan O. Management of single double-J stent failure in malignant ureteral obstruction: tandem ureteral stenting with less frequent stent exchange. Diagn Interv Radiol. 2023 Mar 29;29(2):312-317. doi: 10.5152/dir.2022.21638.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eGao B, Farhat W, Zu\u0026apos;bi F, Chua M, Shiff M, Al-Kutbi R, Pokarowski M, Ming J, Kim J, Dos Santos J, Koyle M. Comparative analysis of suturing technique in pediatric pyeloplasty on surgical outcomes. Pediatr Surg Int. 2021 Nov;37(11):1633-1637. doi: 10.1007/s00383-021-04960-9.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Children, UPJO, Small Renal Pelvis Incision, Modified Suture, Laparoscopic Pyeloplasty","lastPublishedDoi":"10.21203/rs.3.rs-7622736/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7622736/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eLaparoscopic pyeloplasty (LP) is an effective treatment for ureteropelvic junction obstruction (UPJO), but research on reducing renal pelvis incision size and improving suture techniques is limited.\u003c/p\u003e\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eTo compare LP with a modified suture and minimal renal pelvis incision versus standard LP for treating paediatric UPJO.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eA retrospective analysis of 120 paediatric UPJO patients who underwent surgery at the Children's Hospital of Nanjing Hospital from January 2022 to June 2024 was conducted. Among the 120 patients, 103 were male, 17 were female, and the median age was 68.0 months. One hundred cases were left-sided, and 20 were right-sided. The modified group (MG) received LP with a minimal renal pelvis incision and modified suture technique, whereas the control group (CG) underwent standard LP. There were no significant differences between the groups in terms of sex, age, side, or preoperative hydronephrosis (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Surgical and follow-up outcomes were compared.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eAll surgeries were successful without conversion to open surgery. Compared with the CG, the MG had shorter surgery times, less blood loss, shorter hospital stays, and less postoperative haematuria (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). One case (1.59%) of D‒J tube blockage occurred in the MG, whereas seven cases (12.28%) occurred in the CG, with significant difference (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). After a mean follow-up of 7.0\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5 months, there were no significant differences in the anterior‒posterior diameter (APD) of the renal pelvis between the groups (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). The reoperation rate was 1.59% for the MG and 1.75% for the CG (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eCompared with standard LP, LP with a modified suture and minimal renal pelvis incision offers advantages in terms of surgery time, blood loss, hospital stay, and incidence of postoperative haematuria. The reoperation rate and APD recovery were similar between the groups, and the MG had a lower incidence of D‒J tube blockage, making this technique a viable option for treating paediatric UPJO.\u003c/p\u003e","manuscriptTitle":"Comparative Study of a Modified Suture Technique with a Minimal Renal Pelvis Incision in Paediatric Hydronephrosis Treatment","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-28 02:12:39","doi":"10.21203/rs.3.rs-7622736/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a7b6c2b5-6a30-4b09-a43c-b9abbc017e4e","owner":[],"postedDate":"October 28th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-26T12:10:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-28 02:12:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7622736","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7622736","identity":"rs-7622736","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}