Subcapsular Renal Hematoma Following Double-J Stenting in an Infant with VUR: A Rare Complication After Pneumovesicoscopic Leadbetter Ureteroneocystostomy

Subcapsular Renal Hematoma Following Double-J Stenting in an Infant with VUR: A Rare Complication After Pneumovesicoscopic Leadbetter Ureteroneocystostomy | 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 Case Report Subcapsular Renal Hematoma Following Double-J Stenting in an Infant with VUR: A Rare Complication After Pneumovesicoscopic Leadbetter Ureteroneocystostomy Hang Wu, Jingjing Li, Xiaoqi Xuan, Jinlong Yang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6370972/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 Vesicoureteral reflux (VUR) is a prevalent pediatric urological anomaly often complicated by recurrent urinary tract infections (UTIs) and renal injury. While double-J (DJ) stents are commonly placed during surgical correction to prevent obstruction, severe hemorrhagic complications, such as renal subcapsular hematoma, are extremely rare, particularly in infants. Herein, we describe an infant who developed a right subcapsular renal hematoma following pneumovesicoscopic Leadbetter ureteral reimplantation, likely resulting from renal parenchymal injury during retrograde DJ stent insertion. Multimodal imaging guided conservative management, resulting in complete resolution without compromising renal function. This case underscores the importance of infant-specific stenting strategies and heightened surveillance for rare complications in pediatric urology. Vesicoureteral reflux double-J stents infants renal hematoma ureteral reimplantation Figures Figure 1 Figure 2 Figure 3 Introduction Vesicoureteral reflux (VUR), a common congenital urological anomaly in children, is associated with recurrent urinary tract infections (UTIs) and renal scarring. Surgical intervention, such as the Leadbetter ureteroneocystostomy, remains the standard treatment for moderate to severe cases (grades III–V), effectively restoring the anti-reflux mechanism( 1 ). Intraoperative placement of a double-J (DJ) stent is widely adopted to mitigate postoperative obstruction and protect anastomotic sites. Severe hemorrhagic complications, such as subcapsular or perinephric hematomas, are exceptionally rare, particularly in infants, with limited data on etiology or management( 2 , 3 ). In adults, DJ stent-related complications—including migration, encrustation, and hematuria—are well-documented( 4 , 5 ). Notably, life-threatening events like renal parenchymal perforation or hematoma formation are primarily linked to anatomical anomalies, coagulopathy, or iatrogenic injury during stent placement( 6 , 7 ). For instance, Umut Gönülalan et al. reported renal parenchymal perforation in a solitary kidney due to stent misplacement, necessitating urgent intervention( 8 ). In pediatric populations, however, such complications are scarcely reported, likely due to underrecognition or anatomical differences. Infants exhibit unique vulnerabilities, including narrower ureters (< 4–5 mm diameter), fragile mucosal layers, and susceptibility to mechanical trauma during stent insertion( 9 ). This case report describes a 6-month-old male with bilateral high-grade VUR (left grade IV, right grade III) who developed a right subcapsular renal hematoma following pneumovesicoscopic Leadbetter repair. The hematoma, likely caused by parenchymal microvascular injury during retrograde DJ stent placement, underscores the need for heightened awareness of infant-specific risks. By integrating multimodal imaging and multidisciplinary management, this case highlights critical considerations for optimizing stent deployment techniques and postoperative surveillance in pediatric urology. Case Presentation A 6-month-old male infant presented with a 2-month history of recurrent UTIs secondary to VUR, classified as grade IV on the left and grade III on the right. Initial imaging studies, including renal scintigraphy and magnetic resonance urography(MRU), demonstrated left renal atrophy and tortuous ureteral dilation. Voiding cystourethrography (VCUG) (December 2, 2024) confirmed high-grade reflux. Preoperative laboratory evaluations excluded coagulopathy or active infection, with hemoglobin levels within the normal range (102 g/L). The patient underwent bilateral pneumovesicoscopic Leadbetter ureteroneocystostomy under general anesthesia, with bilateral retrograde placement of 4 Fr × 200mm DJ stents. The procedure duration was 123 minutes, with minimal blood loss (< 10 mL). Immediate postoperative imaging revealed appropriate stent positioning(Fig. 1 ). The patient was discharged on postoperative day 6 with stable vital signs and no evidence of acute complications. On postoperative day 15, the patient returned with a palpable right flank mass. Laboratory findings indicated significant anemia (hemoglobin 90 g/L) and microscopic hematuria (red blood cells 9.6/µL, white blood cells 87.7/µL). Ultrasonography identified a right subcapsular hematoma (40 × 18 mm), while contrast-enhanced computed tomography (CT) appeared as a non-enhancing hypodense lesion (24 × 17 mm) (Fig. 2 ). Conservative management included strict activity restriction, intravenous antibiotics, and oral iron supplementation. Serial ultrasonography demonstrated progressive hematoma resolution, decreasing to 27 × 6 mm by postoperative day 20. By postoperative day 38, follow-up ultrasonography confirmed complete hematoma absorption and stable pelvicalyceal dilation (right 5 mm, left 7 mm). After stent removal, no significant hematoma formation was observed(Fig. 3 ). No recurrent bleeding or infection occurred. Further imaging and long-term follow-up are pending to assess renal function and structural integrity. Discussion This case report describes a rare complication of a right subcapsular renal hematoma following bilateral Leadbetter ureteroneocystostomy with DJ stent placement in a 6-month-old infant who suffered from high-grade VUR. While DJ stents are widely used to mitigate postoperative obstruction in pediatric urology, their application in infants carries unique risks due to anatomical and physiological vulnerabilities. Unlike adults, where stent-related complications predominantly involve ureteral irritation, migration, or infection( 10 , 11 ), severe hemorrhagic events in infants, such as renal parenchymal injury, remain exceptionally rare and poorly characterized. The hematoma in this case likely originated from damage to the renal parenchyma during retrograde stent placement. In infants, the renal capsule is loosely attached to the parenchyma, and the renal cortex is thinner compared to adults, rendering it more susceptible to mechanical trauma( 12 ). The sharp tip of the DJ stent, even with careful placement, may inadvertently puncture small cortical vessels or exert localized pressure on the parenchyma, leading to subcapsular bleeding. This mechanism aligns with reports in adults, where stent misplacement or excessive friction against renal tissue has been implicated in hematoma formation( 13 ). However, pediatric cases are distinct due to the compounding effects of developmental fragility and pathological changes from chronic VUR, such as renal scarring and altered tissue elasticity( 14 ). The preoperative presence of left renal atrophy and tortuous ureteral dilation in this patient likely exacerbated mechanical stress during stent insertion, amplifying the risk of parenchymal injury. Early detection of subcapsular hematomas in infants remains challenging. Conventional ultrasound, while non-invasive, often lacks sensitivity for small or non-expanding hematomas, as seen in this case. Contrast-enhanced CT, though diagnostic, poses risks of radiation exposure and contrast-induced nephropathy in this population( 15 ). The hematoma here was incidentally detected during routine postoperative imaging, underscoring the need for vigilant surveillance in high-risk infants. Notably, the absence of gross hematuria or hemodynamic instability in this case highlights the insidious nature of such complications, which may evade clinical suspicion until imaging reveals significant pathology. The unique anatomical characteristics of infants, including smaller renal dimensions, immature vascular networks, and compensatory hypertrophy in kidneys affected by chronic reflux, significantly elevate the risk of iatrogenic injury during stent placement( 16 ). Current stent selection criteria, largely extrapolated from adult protocols, may fail to accommodate the distinct compliance of pediatric renal parenchyma. Stents designed for adult use, which are stiffer and generate higher radial forces, can impose excessive mechanical stress on the infant renal pelvis( 17 ). Additionally, preoperative pathological changes—such as hydronephrosis and fibrotic remodeling secondary to recurrent infections—may distort renal anatomy, increasing the likelihood of stent tip malposition( 18 ). In this case, the coexistence of high-grade VUR, recurrent UTIs, and ureteral fibrosis established a complex anatomical substrate, wherein even technically precise stent deployment could not fully eliminate the risk of parenchymal microvascular injury. Existing studies on DJ stent complications predominantly focus on ureteral outcomes of adults, neglecting parenchymal risks in infants. Prospective registries or multicenter collaborations are needed to quantify the incidence of renal hematomas and establish evidence-based guidelines. Additionally, experimental models simulating pediatric renal mechanics could clarify injury thresholds and inform stent design. Biomechanical studies evaluating the force required to puncture infant renal tissue versus adult tissue might guide the development of softer and atraumatic stent tips. Innovations in biocompatible materials, such as hydrophilic coatings or nano-engineered surfaces, could further reduce friction and tissue adhesion( 19 ), though miniaturization for infant use remains a technical challenge. In conclusion, this case underscores the vulnerability of infant renal parenchyma to mechanical trauma during DJ stent placement. By integrating anatomical insights, advanced imaging, and device innovations, clinicians can better balance the benefits of stenting against its risks in this delicate population. Future research should prioritize the development of infant-specific stent protocols, incorporating preoperative risk stratification based on renal morphology, VUR severity, and infection history. Declarations Ethics Approval and Consent to Participate This case report was reviewed and approved by the Ethics Committee of the Affiliated Children’s Hospital of Jiangnan University (Approval No. WXCH2025-03-085). Written informed consent was obtained from the infant’s legal guardians for participation and publication of clinical data and images. Consent for Publication Written informed consent for publication of anonymized clinical details and images was obtained from the patient's legal guardians. Competing Interests The authors declare that they have no competing interests. Funding: This study was funded by the Major Scientific Research Project of the Wuxi Municipal Health Commission (Grant ID: Z202314). Clinical Trial Registration Clinical trial number: Not applicable. Author Details 1 Department of Pediatric Urology, Affiliated Children’s Hospital of Jiangnan University (Wuxi Children's Hospital), Wuxi, Jiangsu, China. 2 Department of Infectious Diseases, Affiliated Children’s Hospital of Jiangnan University (Wuxi Children's Hospital), Wuxi, Jiangsu, China. Author Contribution H.W. and J.L. collected clinical data, performed the literature review, and drafted the main manuscript text. X.X. contributed to data interpretation and provided critical revision of the manuscript. J.Y. supervised the study, confirmed the diagnosis and treatment strategy, and finalized the manuscript. All authors reviewed and approved the final version of the manuscript. References Puri P, Friedmacher F, Farrugia MK, Sharma S, Esposito C, Mattoo TK. Primary vesicoureteral reflux. NAT REV DIS PRIMERS. [Journal Article; Review]. 2024 2024/10/10;10(1):75. Jayasimha S, Nagasubramanian S, Jayanth ES, Muthukrishna PR, Kumar JC. S. Management of proximal migration of double-J stents after Anderson-Hynes pyeloplasty in children. J PEDIATR UROL [Journal Article]. 2021 2021/6/1;17(3):391–9. Baek M, Au J, Huang GO, Koh CJ. Robot-assisted laparoscopic pyeloureterostomy in infants with duplex systems and upper pole hydronephrosis: Variations in double-J ureteral stenting techniques. J PEDIATR UROL [Journal Article]. 2017;2017/4(113):219–20. Lopes RI, Perrella R, Watanabe CH, Beltrame F, Danilovic A, Murta CB et al. Patients with encrusted ureteral stents can be treated by a single session combined endourological approach. INT BRAZ J UROL [Journal Article]. 2021 2021/5/1;47(3):574–83. Huang C, Liu J, Mao J, Yu L, Gong L, Lai F. Rare complication of ureteral double-J stenting after ureteroscopy: pelvic ectopic renal parenchymal perforation. J INT MED RES [Case Reports; J Article]. 2022;2022/1(1):675843355. Cao C, Kim SY, Kim GH, Shin JH, Nam IC, Alali M et al. Comparison of transradial and transfemoral access for transcatheter arterial embolization of iatrogenic renal hemorrhage. PLOS ONE [Journal Article]. 2021 2021/1/20;16(8):e256130. Iba T, Helms J, Maier CL, Levi M, Scarlatescu E, Levy JH. The role of thromboinflammation in acute kidney injury among patients with septic coagulopathy. J THROMB HAEMOST [Journal Article; Review]. 2024 2024/6/1;22(6):1530–40. Gonulalan U, Akand M, Hasirci E, Kosan M. An unusual complication of a double-J ureteral stent: renal parenchymal perforation in a solitary kidney. TURK J UROL [Journal Article]. 2014;2014(12/1):245–7. Gnech M, Zachou THL, Bogaert A, Castagnetti G, O'Kelly M. F, Update and Summary of the European Association of Urology/European Society of Paediatric Urology Paediatric Guidelines on Vesicoureteral Reflux in Children. EUR UROL. [Journal Article; Review]. 2024 2024/5/1;85(5):433–42. Falahatkar S, Hemmati H, Gholamjani MK. Intracaval migration: an uncommon complication of ureteral Double-J stent placement. J ENDOUROL [Case Reports; J Article]. 2012;2012(2/1):119–21. Jou YC, Cheng MC, Sheen JH, Lin CT, Chen PC. Cauterization of access tract for nephrostomy tube-free percutaneous nephrolithotomy. J ENDOUROL [Journal Article]. 2004 2004/8/1;18(6):547–9. Gobet R, Cisek LJ, Zotti P, Peters CA. Experimental vesicoureteral reflux in the fetus depends on bladder function and causes renal fibrosis. J Urol. [Journal Article; Research Support, Non-U.S. Gov't]. 1998 1998/9/1;160(3 Pt 2):1058–62, 1079. Pradhan A, Rana YP. An uncommon situation of kidney perforation with a ureteric stent. CENT EUR J UROL. [Case Reports. J Article]. 2014;2014/1/20(1):113–4. Lorenzo AJ, Vesicoureteral, Reflux. Renal Scars, and Urinary Tract Infections in Children: A New Way to Think About an Old Problem. EUR UROL. [Comment; Editorial]. 2022 2022/2/1;81(2):155–6. Terlouw LG, Moelker A, Abrahamsen J, Acosta S, Bakker OJ, Baumgartner I et al. European guidelines on chronic mesenteric ischaemia - joint United European Gastroenterology, European Association for Gastroenterology, Endoscopy and Nutrition, European Society of Gastrointestinal and Abdominal Radiology, Netherlands Association of Hepatogastroenterologists, Hellenic Society of Gastroenterology, Cardiovascular and Interventional Radiological Society of Europe, and Dutch Mesenteric Ischemia Study group clinical guidelines on the diagnosis and treatment of patients with chronic mesenteric ischaemia. UNITED EUR GASTROENT. [Journal Article; Practice Guideline; Research Support, Non-U.S. Gov't]. 2020 2020/5/1;8(4):371 – 95. Bateman RM, Sharpe MD, Jagger JE, Ellis CG, Sole-Violan J, Lopez-Rodriguez M et al. 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15–18 March 2016. CRIT CARE. [Congress]. 2016 2016/4/20;20(Suppl 2):94. Vogt B. Stiffness Analysis of Reinforced Ureteral Stents Against Radial Compression: In vitro Study. RES REP UROL [Journal Article]. 2020 2020/1/20;12:583 – 91. Li K, Hu C, Huang W, Si-Tu J, Lu L, Mao Y et al. A modification with threading cannula needle-assisted 4-point suspension fixation for retroperitoneal laparoscopic pyeloplasty in children with ureteropelvic junction obstruction: a cohort study in single center. INT UROL NEPHROL [Journal Article]. 2019 2019/2/1;51(2):193–9. Bi X, Mao Z, Li L, Zhang Y, Yang L, Hou S et al. Janus decellularized membrane with anisotropic cell guidance and anti-adhesion silk-based coatings for spinal dural repair. NAT COMMUN [Journal Article]. 2025 2025/2/15;16(1):1674. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6370972","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":452611742,"identity":"c9bc108e-b81d-400b-8c6b-de650a8ec830","order_by":0,"name":"Hang Wu","email":"","orcid":"","institution":"Affiliated Children’s Hospital of Jiangnan University (Wuxi Childr en's Hospital)","correspondingAuthor":false,"prefix":"","firstName":"Hang","middleName":"","lastName":"Wu","suffix":""},{"id":452611743,"identity":"e0f5f9ee-b038-4417-a27e-bb44f05a2c8b","order_by":1,"name":"Jingjing Li","email":"","orcid":"","institution":"Affiliated Children’s Hospital of Jiangnan University (Wuxi Childr en's Hospital)","correspondingAuthor":false,"prefix":"","firstName":"Jingjing","middleName":"","lastName":"Li","suffix":""},{"id":452611744,"identity":"b08e4e98-5fe8-401b-8e45-9c92bf041171","order_by":2,"name":"Xiaoqi Xuan","email":"","orcid":"","institution":"Affiliated Children’s Hospital of Jiangnan University (Wuxi Childr en's Hospital)","correspondingAuthor":false,"prefix":"","firstName":"Xiaoqi","middleName":"","lastName":"Xuan","suffix":""},{"id":452611745,"identity":"5aa31055-2f10-48e6-80b5-4f3aa63b1114","order_by":3,"name":"Jinlong Yang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyklEQVRIiWNgGAWjYBAC+/mHDxz4YPCPh5+9gUgtBhJsiQdnVByQkew5QLQWHuPDHGcO2BjcSCBSi7l0g8FhxrY7PAw3H2+8wVBjE01Qi+WcAwmHC9ue8TDOTiu2YDiWlttAUM+BhAOHZ7Yx8zBL55hJMDYcJkZLYsNhXqAWNskzRGoxuJHMcJjnzGEeHgkeIrVI9hxjAAZyGlAH0C8JxPiFn73/84cPBjb29scPb7zxocaGCL8gO1IigRTlEC2k6hgFo2AUjIKRAQBv00U8pCv1DQAAAABJRU5ErkJggg==","orcid":"","institution":"Affiliated Children’s Hospital of Jiangnan University (Wuxi Childr en's Hospital)","correspondingAuthor":true,"prefix":"","firstName":"Jinlong","middleName":"","lastName":"Yang","suffix":""}],"badges":[],"createdAt":"2025-04-03 16:23:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6370972/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6370972/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":82580373,"identity":"b610cf74-cf02-4182-8ec4-e0ee20267d63","added_by":"auto","created_at":"2025-05-13 06:31:38","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":102201,"visible":true,"origin":"","legend":"\u003cp\u003ePostoperative imaging demonstrating bilateral double-J stent placement following pneumovesicoscopic Leadbetter ureteroneocystostomy.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6370972/v1/817fa0a1ffafe8ce8ef0610e.png"},{"id":82580370,"identity":"20ba3b8e-c18e-4a23-92a9-1dc80d76047c","added_by":"auto","created_at":"2025-05-13 06:31:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":88017,"visible":true,"origin":"","legend":"\u003cp\u003eNon-contrast and contrast-enhanced computed tomography (CT) revealing right subcapsular renal hematoma.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6370972/v1/1b0865abb5e5a658238bca58.png"},{"id":82580377,"identity":"443d2ba9-e1e1-444a-850b-963afee20b1c","added_by":"auto","created_at":"2025-05-13 06:31:38","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":543238,"visible":true,"origin":"","legend":"\u003cp\u003eRetrieved double-J stents as part of routine second-look procedure following Leadbetter ureteroneocystostomy; the proximal end of the right stent shows poor typical coiling.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6370972/v1/35a49fe83928bb424b066c59.png"},{"id":109170250,"identity":"9c0648d8-a7b2-4651-ae20-549efaa3acf8","added_by":"auto","created_at":"2026-05-13 08:46:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1029242,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6370972/v1/2a95e7bb-57df-42c4-9d3e-651858f37a6b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Subcapsular Renal Hematoma Following Double-J Stenting in an Infant with VUR: A Rare Complication After Pneumovesicoscopic Leadbetter Ureteroneocystostomy","fulltext":[{"header":"Introduction","content":"\u003cp\u003eVesicoureteral reflux (VUR), a common congenital urological anomaly in children, is associated with recurrent urinary tract infections (UTIs) and renal scarring. Surgical intervention, such as the Leadbetter ureteroneocystostomy, remains the standard treatment for moderate to severe cases (grades III\u0026ndash;V), effectively restoring the anti-reflux mechanism(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Intraoperative placement of a double-J (DJ) stent is widely adopted to mitigate postoperative obstruction and protect anastomotic sites. Severe hemorrhagic complications, such as subcapsular or perinephric hematomas, are exceptionally rare, particularly in infants, with limited data on etiology or management(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn adults, DJ stent-related complications\u0026mdash;including migration, encrustation, and hematuria\u0026mdash;are well-documented(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). Notably, life-threatening events like renal parenchymal perforation or hematoma formation are primarily linked to anatomical anomalies, coagulopathy, or iatrogenic injury during stent placement(\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). For instance, Umut G\u0026ouml;n\u0026uuml;lalan et al. reported renal parenchymal perforation in a solitary kidney due to stent misplacement, necessitating urgent intervention(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). In pediatric populations, however, such complications are scarcely reported, likely due to underrecognition or anatomical differences. Infants exhibit unique vulnerabilities, including narrower ureters (\u0026lt;\u0026thinsp;4\u0026ndash;5 mm diameter), fragile mucosal layers, and susceptibility to mechanical trauma during stent insertion(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThis case report describes a 6-month-old male with bilateral high-grade VUR (left grade IV, right grade III) who developed a right subcapsular renal hematoma following pneumovesicoscopic Leadbetter repair. The hematoma, likely caused by parenchymal microvascular injury during retrograde DJ stent placement, underscores the need for heightened awareness of infant-specific risks. By integrating multimodal imaging and multidisciplinary management, this case highlights critical considerations for optimizing stent deployment techniques and postoperative surveillance in pediatric urology.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 6-month-old male infant presented with a 2-month history of recurrent UTIs secondary to VUR, classified as grade IV on the left and grade III on the right. Initial imaging studies, including renal scintigraphy and magnetic resonance urography(MRU), demonstrated left renal atrophy and tortuous ureteral dilation. Voiding cystourethrography (VCUG) (December 2, 2024) confirmed high-grade reflux. Preoperative laboratory evaluations excluded coagulopathy or active infection, with hemoglobin levels within the normal range (102 g/L).\u003c/p\u003e \u003cp\u003eThe patient underwent bilateral pneumovesicoscopic Leadbetter ureteroneocystostomy under general anesthesia, with bilateral retrograde placement of 4 Fr \u0026times; 200mm DJ stents. The procedure duration was 123 minutes, with minimal blood loss (\u0026lt;\u0026thinsp;10 mL). Immediate postoperative imaging revealed appropriate stent positioning(Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The patient was discharged on postoperative day 6 with stable vital signs and no evidence of acute complications.\u003c/p\u003e \u003cp\u003eOn postoperative day 15, the patient returned with a palpable right flank mass. Laboratory findings indicated significant anemia (hemoglobin 90 g/L) and microscopic hematuria (red blood cells 9.6/\u0026micro;L, white blood cells 87.7/\u0026micro;L). Ultrasonography identified a right subcapsular hematoma (40 \u0026times; 18 mm), while contrast-enhanced computed tomography (CT) appeared as a non-enhancing hypodense lesion (24 \u0026times; 17 mm) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Conservative management included strict activity restriction, intravenous antibiotics, and oral iron supplementation. Serial ultrasonography demonstrated progressive hematoma resolution, decreasing to 27 \u0026times; 6 mm by postoperative day 20.\u003c/p\u003e \u003cp\u003eBy postoperative day 38, follow-up ultrasonography confirmed complete hematoma absorption and stable pelvicalyceal dilation (right 5 mm, left 7 mm). After stent removal, no significant hematoma formation was observed(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). No recurrent bleeding or infection occurred. Further imaging and long-term follow-up are pending to assess renal function and structural integrity.\u003c/p\u003e "},{"header":"Discussion","content":"\u003cp\u003eThis case report describes a rare complication of a right subcapsular renal hematoma following bilateral Leadbetter ureteroneocystostomy with DJ stent placement in a 6-month-old infant who suffered from high-grade VUR. While DJ stents are widely used to mitigate postoperative obstruction in pediatric urology, their application in infants carries unique risks due to anatomical and physiological vulnerabilities. Unlike adults, where stent-related complications predominantly involve ureteral irritation, migration, or infection(\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e), severe hemorrhagic events in infants, such as renal parenchymal injury, remain exceptionally rare and poorly characterized.\u003c/p\u003e \u003cp\u003eThe hematoma in this case likely originated from damage to the renal parenchyma during retrograde stent placement. In infants, the renal capsule is loosely attached to the parenchyma, and the renal cortex is thinner compared to adults, rendering it more susceptible to mechanical trauma(\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). The sharp tip of the DJ stent, even with careful placement, may inadvertently puncture small cortical vessels or exert localized pressure on the parenchyma, leading to subcapsular bleeding. This mechanism aligns with reports in adults, where stent misplacement or excessive friction against renal tissue has been implicated in hematoma formation(\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). However, pediatric cases are distinct due to the compounding effects of developmental fragility and pathological changes from chronic VUR, such as renal scarring and altered tissue elasticity(\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). The preoperative presence of left renal atrophy and tortuous ureteral dilation in this patient likely exacerbated mechanical stress during stent insertion, amplifying the risk of parenchymal injury.\u003c/p\u003e \u003cp\u003eEarly detection of subcapsular hematomas in infants remains challenging. Conventional ultrasound, while non-invasive, often lacks sensitivity for small or non-expanding hematomas, as seen in this case. Contrast-enhanced CT, though diagnostic, poses risks of radiation exposure and contrast-induced nephropathy in this population(\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). The hematoma here was incidentally detected during routine postoperative imaging, underscoring the need for vigilant surveillance in high-risk infants. Notably, the absence of gross hematuria or hemodynamic instability in this case highlights the insidious nature of such complications, which may evade clinical suspicion until imaging reveals significant pathology.\u003c/p\u003e \u003cp\u003eThe unique anatomical characteristics of infants, including smaller renal dimensions, immature vascular networks, and compensatory hypertrophy in kidneys affected by chronic reflux, significantly elevate the risk of iatrogenic injury during stent placement(\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). Current stent selection criteria, largely extrapolated from adult protocols, may fail to accommodate the distinct compliance of pediatric renal parenchyma. Stents designed for adult use, which are stiffer and generate higher radial forces, can impose excessive mechanical stress on the infant renal pelvis(\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). Additionally, preoperative pathological changes\u0026mdash;such as hydronephrosis and fibrotic remodeling secondary to recurrent infections\u0026mdash;may distort renal anatomy, increasing the likelihood of stent tip malposition(\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). In this case, the coexistence of high-grade VUR, recurrent UTIs, and ureteral fibrosis established a complex anatomical substrate, wherein even technically precise stent deployment could not fully eliminate the risk of parenchymal microvascular injury.\u003c/p\u003e \u003cp\u003eExisting studies on DJ stent complications predominantly focus on ureteral outcomes of adults, neglecting parenchymal risks in infants. Prospective registries or multicenter collaborations are needed to quantify the incidence of renal hematomas and establish evidence-based guidelines. Additionally, experimental models simulating pediatric renal mechanics could clarify injury thresholds and inform stent design. Biomechanical studies evaluating the force required to puncture infant renal tissue versus adult tissue might guide the development of softer and atraumatic stent tips. Innovations in biocompatible materials, such as hydrophilic coatings or nano-engineered surfaces, could further reduce friction and tissue adhesion(\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e), though miniaturization for infant use remains a technical challenge.\u003c/p\u003e \u003cp\u003eIn conclusion, this case underscores the vulnerability of infant renal parenchyma to mechanical trauma during DJ stent placement. By integrating anatomical insights, advanced imaging, and device innovations, clinicians can better balance the benefits of stenting against its risks in this delicate population. Future research should prioritize the development of infant-specific stent protocols, incorporating preoperative risk stratification based on renal morphology, VUR severity, and infection history.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics Approval and Consent to Participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis case report was reviewed and approved by the Ethics Committee of the Affiliated Children\u0026rsquo;s Hospital of Jiangnan University (Approval No. WXCH2025-03-085). Written informed consent was obtained from the infant\u0026rsquo;s legal guardians for participation and publication of clinical data and images.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent for publication of anonymized clinical details and images was obtained from the patient\u0026apos;s legal guardians.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was funded by the Major Scientific Research Project of the Wuxi Municipal Health Commission (Grant ID: Z202314).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical Trial Registration\u0026nbsp;\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eClinical trial number: Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Details\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1 Department of Pediatric Urology, Affiliated Children\u0026rsquo;s Hospital of Jiangnan University (Wuxi Children\u0026apos;s Hospital), Wuxi, Jiangsu, China.\u003cbr\u003e\u0026nbsp;2 Department of Infectious Diseases, Affiliated Children\u0026rsquo;s Hospital of Jiangnan University (Wuxi Children\u0026apos;s Hospital), Wuxi, Jiangsu, China.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eH.W. and J.L. collected clinical data, performed the literature review, and drafted the main manuscript text. X.X. contributed to data interpretation and provided critical revision of the manuscript. J.Y. supervised the study, confirmed the diagnosis and treatment strategy, and finalized the manuscript. All authors reviewed and approved the final version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePuri P, Friedmacher F, Farrugia MK, Sharma S, Esposito C, Mattoo TK. Primary vesicoureteral reflux. NAT REV DIS PRIMERS. [Journal Article; Review]. 2024 2024/10/10;10(1):75.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJayasimha S, Nagasubramanian S, Jayanth ES, Muthukrishna PR, Kumar JC. S. Management of proximal migration of double-J stents after Anderson-Hynes pyeloplasty in children. J PEDIATR UROL [Journal Article]. 2021 2021/6/1;17(3):391\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaek M, Au J, Huang GO, Koh CJ. 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[Congress]. 2016 2016/4/20;20(Suppl 2):94.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVogt B. Stiffness Analysis of Reinforced Ureteral Stents Against Radial Compression: In vitro Study. RES REP UROL [Journal Article]. 2020 2020/1/20;12:583\u0026thinsp;\u0026ndash;\u0026thinsp;91.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi K, Hu C, Huang W, Si-Tu J, Lu L, Mao Y et al. A modification with threading cannula needle-assisted 4-point suspension fixation for retroperitoneal laparoscopic pyeloplasty in children with ureteropelvic junction obstruction: a cohort study in single center. INT UROL NEPHROL [Journal Article]. 2019 2019/2/1;51(2):193\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBi X, Mao Z, Li L, Zhang Y, Yang L, Hou S et al. Janus decellularized membrane with anisotropic cell guidance and anti-adhesion silk-based coatings for spinal dural repair. NAT COMMUN [Journal Article]. 2025 2025/2/15;16(1):1674.\u003c/span\u003e\u003c/li\u003e\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":"Vesicoureteral reflux, double-J stents, infants, renal hematoma, ureteral reimplantation","lastPublishedDoi":"10.21203/rs.3.rs-6370972/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6370972/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eVesicoureteral reflux (VUR) is a prevalent pediatric urological anomaly often complicated by recurrent urinary tract infections (UTIs) and renal injury. While double-J (DJ) stents are commonly placed during surgical correction to prevent obstruction, severe hemorrhagic complications, such as renal subcapsular hematoma, are extremely rare, particularly in infants. Herein, we describe an infant who developed a right subcapsular renal hematoma following pneumovesicoscopic Leadbetter ureteral reimplantation, likely resulting from renal parenchymal injury during retrograde DJ stent insertion. Multimodal imaging guided conservative management, resulting in complete resolution without compromising renal function. This case underscores the importance of infant-specific stenting strategies and heightened surveillance for rare complications in pediatric urology.\u003c/p\u003e","manuscriptTitle":"Subcapsular Renal Hematoma Following Double-J Stenting in an Infant with VUR: A Rare Complication After Pneumovesicoscopic Leadbetter Ureteroneocystostomy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-13 06:31:33","doi":"10.21203/rs.3.rs-6370972/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":"95e27db8-e774-4c08-adfc-a01c25441a28","owner":[],"postedDate":"May 13th, 2025","published":true,"recentEditorialEvents":[{"type":"decision","content":"Withdrawn","date":"2026-05-13T08:30:42+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-13T08:43:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-13 06:31:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6370972","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6370972","identity":"rs-6370972","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}