Diagnostic Accuracy of Ascending Cystourethrogram for Localising Recto-Urinary Fistulas in Non-Colostomized Male Neonates with High Anorectal Malformations: Cairo University Paediatric Surgery Experience

Diagnostic Accuracy of Ascending Cystourethrogram for Localising Recto-Urinary Fistulas in Non-Colostomized Male Neonates with High Anorectal Malformations: Cairo University Paediatric Surgery Experience | 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 Diagnostic Accuracy of Ascending Cystourethrogram for Localising Recto-Urinary Fistulas in Non-Colostomized Male Neonates with High Anorectal Malformations: Cairo University Paediatric Surgery Experience Urszula Zacharska, Ahmed Fares, Mostafa Gad, Hesham Elsaket, Ahmed Azzam This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8575330/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Mar, 2026 Read the published version in Egyptian Pediatric Association Gazette → Version 1 posted 17 You are reading this latest preprint version Abstract BACKGROUND Accurate preoperative identification of recto-urinary fistulas in male neonates with high anorectal malformations (ARMs) is essential for surgical planning, especially when considering single-stage repair. The ascending cystourethrogram (ACU) provides a simple, minimally invasive approach that eliminates the need for a preliminary colostomy. METHODS This prospective study included 35 male neonates with high ARM who underwent ACU before definitive repair. The presence and level of recto-urinary fistulas are recorded and compared with intraoperative findings. When imaging did not demonstrate the fistula, distal colostrography is performed to confirm the diagnosis. RESULTS ACU identified recto-urinary fistulas in 30 of 35 neonates (85.7%; 95% CI: 70.6–94.1%). Detected fistulas included recto-bladder neck (14.3%), recto-prostatic (42.9%), and recto-bulbar (28.6%) types. In five cases (14.3%), a fistula was not visualised on ACU; however, distal colostogram confirmed the diagnosis in four. Relative to intraoperative findings, ACU demonstrated a sensitivity of 85.7% and a positive predictive value of 100%. CONCLUSION ACU is a reliable, minimally invasive, and readily available technique for early localisation of recto-urinary fistulas in male neonates with high ARM, demonstrating close correlation with intraoperative findings. It can be safely performed within the first 24 hours of life, enabling prompt anatomical assessment and supporting the appropriate selection of candidates for single-stage repair. These findings reinforce ACU’s role as a practical first-line diagnostic tool in the management of high anorectal malformations. Figures Figure 1 Figure 2 Figure 3 BACKGROUND Congenital recto-urethral fistula (RUF) is the most common form of anorectal malformations (ARMs) found in boys [ 1 ]. Differentiating RUF from lower fistulas, such as recto-bulbar connections, is often challenging in the neonatal period and requires a reliable imaging technique to accurately delineate the anatomy of the distal rectal pouch and its communication with the urinary tract. There has been a growing trend toward single-stage definitive repair of complex ARMs, such as the single-stage laparoscopic-assisted anorectal pull-through (SILAARP) [ 2 ]. The main limitation of this approach, however, is the lack of information about whether a recto-urinary fistula is present and, if so, its exact level. Accurate preoperative localisation of the fistula is crucial for planning such procedures. Performing a colostomy in the neonatal period provides safe access for distal colostography. It helps prevent complications, such as inadvertent passage of faecal material through the fistula during anal contrast injection, which could result in urinary contamination, infection, or fistula injury. Several diagnostic modalities have been evaluated for this purpose, including ascending cystourethrogram (ACU), high-pressure colostogram [ 3 ], MRI [ 4 ], cystoscopy [ 5 ], and transperineal ultrasound [ 6 ]. Among these, the ACU stands out as a simple, minimally invasive, and cost-effective technique. This study evaluated 35 male neonates to assess the effectiveness and diagnostic accuracy of ACU in detecting recto-urinary fistulas and determining their anatomical level. METHODS This prospective study enrolled 35 male neonates with a confirmed diagnosis of high anorectal malformation who were clinically stable following initial resuscitation and scheduled to undergo SILAARP. The study excluded female neonates, males with low anorectal malformations, patients with major associated anomalies precluding surgery, those with hemodynamic instability that prevented imaging, individuals with prior definitive anorectal surgery, and patients with incomplete imaging or operative records. The institutional review board approved the study, and the parents or legal guardians of all neonates provided written informed consent before participation. Following resuscitation and laboratory investigations, the neonate was prepared for the ACU study. The ACU findings were then compared with intraoperative observations and, in cases where the fistula was not visualised, with distal colostogram results. The team commenced antibiotics (co-amoxiclav and metronidazole) before and after contrast installation. The following equipment was used (radio-opaque contrast Urografin 76% (Amidotrizoate meglumine; Sodium amidotrizoate), fluoroscopic X-ray machine, 6 Fr Neleton catheter, and 50 ml syringe). The contrast is diluted by 50% with injectable normal saline. The patient should be positioned in the lateral position (Fig. 1 ) with the hips and knees flexed. The fluoroscopic C-arm is placed over the patient’s pelvis. Without general anaesthesia, the operator cleans the glans penis and the urethral meatus with a sterilising solution. The catheter was then placed just inside the urethral meatus, with caution not to overinsert it. The contrast medium was injected through the catheter under controlled pressure to visualise the urinary tract and any fistulous communication, using dynamic fluoroscopy. The operator gently stretches the penis and manually occludes the urethral meatus to prevent contrast medium leakage. The images are reviewed in real time by the performing surgeon. The study is considered negative when the images show no fistula. Data were analysed using descriptive statistics. Categorical variables, including the presence and anatomical level of recto-urinary fistulas, were summarised as frequencies and percentages. The team assessed ACU’s diagnostic performance using sensitivity and positive predictive value, referencing intraoperative findings as the standard. Specificity and negative predictive value could not be reliably calculated because no true-negative cases were present in this cohort of patients with high anorectal malformations. RESULTS The study successfully identified recto-urinary fistulas in 30 of 35 cases (85.7%; 95% CI: 70.6–94.1%), while 5 cases (14.3%) showed no visible fistulous communication on ACU. Using intraoperative findings as the reference standard, ACU demonstrated a sensitivity of 85.7% (95% CI: 70.6–94.1%) and a positive predictive value of 100% (95% CI: 88.4–100%). Specificity and negative predictive value could not be calculated because there were no true-negative cases in this cohort; all patients had high anorectal malformations. Among the visualised cases, 5 (14.3%) had recto-bladder neck fistulas (Fig. 2 A),15 (42.9%) had recto-prostatic fistulas (Fig. 2 B), and 10 (28.6%) had recto-bulbar fistulas (Fig. 2 C). The team performed colostomies in five cases in which ACU did not demonstrate the fistula, enabling further anatomical assessment and staged repair. In one case, neither the ACU nor the distal colostogram identified the fistula; however, intraoperative PSARP revealed a small rectobulbar fistula. DISCUSSION This study demonstrated that ACU successfully identified recto-urinary fistulas in 85.7% of non-colostomized male neonates with ARMs. This finding supports ACU's role as a valuable primary imaging modality for preoperative planning, providing essential anatomical information without the need for a preliminary colostomy. By defining the level of the recto-urinary fistula, ACU supports the safe selection of candidates for single-stage procedures such as SILAARP and facilitates an appropriate surgical strategy (Fig. 3 ). A major advantage of ACU is that it can be performed without sedation or general anaesthesia, unlike MRI or cystoscopy. The ACU technique provides real-time visualisation of the urinary tract and fistulous communication, allowing immediate interpretation by the performing surgeon. It is simple to perform, minimally invasive, cost-effective, and readily available in most centres. In a previous study with a comparable patient cohort, preoperative fistula level determination achieved the highest diagnostic accuracy (70%), followed by colostogram (66%) and Voiding Cystourethrogram (VCUG) (58%) [ 3 ]. While none were statistically superior, ACU offers a distinct advantage as a minimally invasive, real-time imaging technique that does not require general anaesthesia, making it suitable for early preoperative evaluation. A 2023 study found that high-pressure distal colostogram achieved greater accuracy than MRI in defining fistula type among males with ARMs after colostomy. It is recommended that VCUG be performed to reduce the risk of false-negative results when no fistula is detected [ 4 ]. However, this approach requires a prior colostomy and multiple imaging procedures, which can delay definitive repair. In our study, ACU identified fistulas in 85.7% of cases, outperforming MRI, which correctly detected fistula presence in approximately 76.6% of patients [ 5 ]. These findings reinforce ACU’s value as a practical, first-line diagnostic tool for non-colostomized neonates. MRI remains costly and less accessible in many settings. Initial blind cystoscopy has been shown to miss up to half of fistulas, although a second procedure can identify all fistulas and correctly locate most (80%) [ 6 ]. Despite this, cystoscopy remains invasive, carries a risk of urethral trauma, and may still show discrepancies when compared with intraoperative findings. Another preoperative technique, transperineal ultrasound, provides a noninvasive means of assessing fistula anatomy. Still, its accuracy depends heavily on operator skill, patient anatomy, and fistula complexity, often making precise localisation difficult [ 7 ]. A small study suggested that neonatal perineal ultrasound could identify fistulous tracts and enable one-stage repair in selected male neonates without perineal fistula [ 8 ]; however, the limited sample size and reliance on expert radiologic interpretation limit its broader use. In contrast, ACU is straightforward, reproducible, and allows real-time assessment by the surgeon, making it a more practical and widely accessible preoperative tool. A limitation of this study is the relatively small sample size and the absence of interobserver assessment, which may affect the precision and reproducibility of estimates. Nevertheless, ACU demonstrated consistently high detection rates in this cohort, highlighting its reliability as a primary imaging tool. Despite this, the findings highlight the diagnostic value of ACU as a first-line investigation in non-colostomized male neonates with high anorectal malformations, potentially serving as a practical alternative to more expensive imaging modalities for preoperative fistula localisation before single-stage repair. While comparisons with other modalities, such as MRI, distal colostogram, or cystoscopy, are promising, larger studies are warranted to validate ACU’s superior performance across broader populations. CONCLUSION ACU is a reliable, minimally invasive, and readily available technique for preoperative localisation of recto-urinary fistulas in non-colostomized male neonates with high ARM. In our series, it accurately identified the fistula level in most cases, providing crucial anatomical detail for surgical planning while avoiding the risks, costs, and delays associated with colostography or other complex imaging methods. ACU can be safely performed within the first 24 hours of life, allowing early and accurate identification of recto-urinary fistulas. This early anatomical definition supports the safe selection of candidates for single-stage repair. It reinforces ACU’s value as a practical first-line diagnostic tool in the management of high anorectal malformations. Declarations HUMAN ETHICS AND CONSENT TO PARTICIPATE The study was approved by the Research Ethics Committee (REC), Faculty of Medicine, Cairo University. Written informed consent was obtained from the parents or legal guardians of all participating neonates prior to enrolment in the study. All procedures were conducted in accordance with the ethical standards of the institutional research committee and with the principles of the Declaration of Helsinki. FUNDING This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Author Contribution H.E. and A.F. conceived and designed the study. A.A. collected the clinical and imaging data. A.A. and U.Z. performed the data analysis and interpretation. A.A. and U.Z. prepared the manuscript, figures and illustrations. All authors critically revised the manuscript and approved the final version for submission. Acknowledgement The author wishes to express profound gratitude and deep respect to the late Professor Hesham Elsaket, who served as the main supervisor of this MD thesis entitled in Cairo University.Professor Elsaket’s invaluable guidance, exceptional surgical insight, and unwavering academic support were fundamental to the conception, execution, and completion of this work. His dedication to pediatric surgery, commitment to scientific excellence, and mentorship have left a lasting impact on both this research and the author’s professional development.His untimely passing during the COVID-19 pandemic is a great loss to the medical and academic community. This work is respectfully dedicated to his memory, in recognition of his enduring contributions and inspirational leadership. Data Availability The data supporting the findings of this study were generated in the Pediatric Surgery Department at Cairo University and include clinical, imaging, and intraoperative data from neonates with high anorectal malformations. Due to the sensitive nature of patient data and ethical restrictions, the datasets are not publicly available. De-identified data are available from the corresponding author upon reasonable request and with appropriate institutional approval. References Pena A (1995) Anorectal malformations. J Japanese Soc Pediatr Surg 31(5):718–731 Somme S, Langer JC (2004) Primary versus staged pull-through for the treatment of Hirschsprung disease. Seminars in Pediatric Surgery, vol 13. Elsevier BV, pp 249–255. 4 Tofft L, Salö M, Arnbjörnsson E, Stenström P (2021) Accuracy of pre-operative fistula diagnostics in anorectal malformations. BMC pediatrics , 21 (1), p.283 Bai J, Zhang B, Lin K (2023) Preoperative fistula diagnostics in male anorectal malformations after colostomy: a single-center experience. BMC Medical Imaging , 23 (1), p.139 Ghasi RG, Mittal MK, Bagga D (2018) Anorectal malformations: Role of MRI in preoperative evaluation. Indian J Radiol Imaging 28(02):187–194 Shojaeian R, Hiradfar M, Taqanaki PB, Ameri L, Mashhadi MP (2023) Evaluating the utility of cystoscopy, distal colostography, and sonography for locating the fistula in patients with anorectal malformation: a case series. Annals Med Surg 85(5):1436–1441 Maconi G, Greco MT, Asthana AK (2017) Transperineal ultrasound for perianal fistulas and abscesses–a systematic review and meta-analysis. Ultraschall der Medizin-European J Ultrasound 38(03):265–272 Giné C, Coma A, García L, Laín A, Barber I, Maluje R, López M (2021) Neonatal Ultrasound for Anorectal Malformations in Male Newborns Without Perineal Fistula: A Good Diagnostic Tool for A Safe One-Staged Surgery. Archives Clin Med Case Rep 5:811–820 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 09 Mar, 2026 Read the published version in Egyptian Pediatric Association Gazette → Version 1 posted Editorial decision: Revision requested 03 Feb, 2026 Reviews received at journal 24 Jan, 2026 Reviews received at journal 23 Jan, 2026 Reviews received at journal 22 Jan, 2026 Reviews received at journal 19 Jan, 2026 Reviewers agreed at journal 19 Jan, 2026 Reviewers agreed at journal 18 Jan, 2026 Reviewers agreed at journal 18 Jan, 2026 Reviewers agreed at journal 18 Jan, 2026 Reviews received at journal 17 Jan, 2026 Reviewers agreed at journal 17 Jan, 2026 Reviewers agreed at journal 16 Jan, 2026 Reviewers agreed at journal 16 Jan, 2026 Reviewers invited by journal 16 Jan, 2026 Editor assigned by journal 15 Jan, 2026 Submission checks completed at journal 15 Jan, 2026 First submitted to journal 11 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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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-8575330","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":577076107,"identity":"33465cce-fa0a-40a8-b248-f84c5114d770","order_by":0,"name":"Urszula Zacharska","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7ElEQVRIiWNgGAWjYPCCA0DMxsDwAUSxk6KFcQaIYiZFCzMPiE1Ii8H5A8wfftTckTfvP5b42ebXNnk+ZgbGDx9z8Gg5cIDBsOfYM8M5N9IOS+f23TZsY2Zglpy5DY+Wgw0MCbwNhxlnSLA3SOf23GYEamFj5sWn5TADw8G/DYftZ/Afb/5t2XPbnrCWYwyMzUBbEmcwpB2TZvhxO5GgFskzjM3MMscOJ8+QSEuz7G24ndzGzNiM1y985w8f/vim5rDtDP5jxjd+/LltO7+9+eCHj3i0MDAwNiCx29BFCIM/pCgeBaNgFIyCkQIA7ylSn5S7pdUAAAAASUVORK5CYII=","orcid":"","institution":"University of Oxford","correspondingAuthor":true,"prefix":"","firstName":"Urszula","middleName":"","lastName":"Zacharska","suffix":""},{"id":577076108,"identity":"e8d37a88-f143-4144-92b6-e45f5992adf5","order_by":1,"name":"Ahmed Fares","email":"","orcid":"","institution":"Fayoum University Hospitals","correspondingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"","lastName":"Fares","suffix":""},{"id":577076109,"identity":"5bd8848a-28e8-4393-8cd2-7bf8cd185bd5","order_by":2,"name":"Mostafa Gad","email":"","orcid":"","institution":"Cairo University Specialized Pediatric Hospital (CUSPH)","correspondingAuthor":false,"prefix":"","firstName":"Mostafa","middleName":"","lastName":"Gad","suffix":""},{"id":577076110,"identity":"d9dc37ea-989d-49ab-bdc4-ab4217a4cfd2","order_by":3,"name":"Hesham Elsaket","email":"","orcid":"","institution":"Cairo University Specialized Pediatric Hospital (CUSPH)","correspondingAuthor":false,"prefix":"","firstName":"Hesham","middleName":"","lastName":"Elsaket","suffix":""},{"id":577076111,"identity":"99835cdc-5825-459c-8425-b4b981da6548","order_by":4,"name":"Ahmed Azzam","email":"","orcid":"","institution":"Cairo University Specialized Pediatric Hospital (CUSPH)","correspondingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"","lastName":"Azzam","suffix":""}],"badges":[],"createdAt":"2026-01-11 18:38:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8575330/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8575330/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s43054-026-00527-2","type":"published","date":"2026-03-09T15:58:58+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":101213982,"identity":"a7ec0cab-43f5-4d30-b6bb-52d552e78eec","added_by":"auto","created_at":"2026-01-27 10:33:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2350730,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe patient in the lateral position for the Ascending Cystourethrogram (ACU).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-8575330/v1/cefdc5802cad8e7a716f4035.png"},{"id":101214384,"identity":"52c16597-2673-4e91-920e-78f258e5749e","added_by":"auto","created_at":"2026-01-27 10:34:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":950982,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAscending Cystourethrogram (ACU) images demonstrating different types of recto-urinary fistulas (arrows): (A) recto-bladder neck with associated megaurethra (*), (B) recto-prostatic fistula, (C) recto-bulbar fistula.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-8575330/v1/400b79882294c759f5e7a8cb.png"},{"id":101214036,"identity":"4ef5ee91-991d-46f4-9720-69c28eddcdf0","added_by":"auto","created_at":"2026-01-27 10:33:15","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":166456,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDiagnostic algorithm showing the role of ACU in determining the appropriate surgical strategy for male neonates with high anorectal malformation. When a prostatic or bladder neck fistula is visualised, the team performs SILAARP; for bulbar or unvisualised fistulas, they follow a three-stage approach.\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"FIgure3.png","url":"https://assets-eu.researchsquare.com/files/rs-8575330/v1/a0c9497ce351eba5d8dcf7e6.png"},{"id":104740334,"identity":"27379484-4878-4fe1-ae27-9885a59f7d18","added_by":"auto","created_at":"2026-03-16 16:16:54","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4712872,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8575330/v1/854c709e-3052-4722-8a07-eca2ef0991e0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Diagnostic Accuracy of Ascending Cystourethrogram for Localising Recto-Urinary Fistulas in Non-Colostomized Male Neonates with High Anorectal Malformations: Cairo University Paediatric Surgery Experience","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eCongenital recto-urethral fistula (RUF) is the most common form of anorectal malformations (ARMs) found in boys [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Differentiating RUF from lower fistulas, such as recto-bulbar connections, is often challenging in the neonatal period and requires a reliable imaging technique to accurately delineate the anatomy of the distal rectal pouch and its communication with the urinary tract.\u003c/p\u003e \u003cp\u003eThere has been a growing trend toward single-stage definitive repair of complex ARMs, such as the single-stage laparoscopic-assisted anorectal pull-through (SILAARP) [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The main limitation of this approach, however, is the lack of information about whether a recto-urinary fistula is present and, if so, its exact level. Accurate preoperative localisation of the fistula is crucial for planning such procedures.\u003c/p\u003e \u003cp\u003ePerforming a colostomy in the neonatal period provides safe access for distal colostography. It helps prevent complications, such as inadvertent passage of faecal material through the fistula during anal contrast injection, which could result in urinary contamination, infection, or fistula injury. Several diagnostic modalities have been evaluated for this purpose, including ascending cystourethrogram (ACU), high-pressure colostogram [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], MRI [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], cystoscopy [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], and transperineal ultrasound [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Among these, the ACU stands out as a simple, minimally invasive, and cost-effective technique. This study evaluated 35 male neonates to assess the effectiveness and diagnostic accuracy of ACU in detecting recto-urinary fistulas and determining their anatomical level.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003eThis prospective study enrolled 35 male neonates with a confirmed diagnosis of high anorectal malformation who were clinically stable following initial resuscitation and scheduled to undergo SILAARP. The study excluded female neonates, males with low anorectal malformations, patients with major associated anomalies precluding surgery, those with hemodynamic instability that prevented imaging, individuals with prior definitive anorectal surgery, and patients with incomplete imaging or operative records. The institutional review board approved the study, and the parents or legal guardians of all neonates provided written informed consent before participation. Following resuscitation and laboratory investigations, the neonate was prepared for the ACU study. The ACU findings were then compared with intraoperative observations and, in cases where the fistula was not visualised, with distal colostogram results.\u003c/p\u003e \u003cp\u003eThe team commenced antibiotics (co-amoxiclav and metronidazole) before and after contrast installation. The following equipment was used (radio-opaque contrast Urografin 76% (Amidotrizoate meglumine; Sodium amidotrizoate), fluoroscopic X-ray machine, 6 Fr Neleton catheter, and 50 ml syringe). The contrast is diluted by 50% with injectable normal saline. The patient should be positioned in the lateral position (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) with the hips and knees flexed. The fluoroscopic C-arm is placed over the patient\u0026rsquo;s pelvis.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWithout general anaesthesia, the operator cleans the glans penis and the urethral meatus with a sterilising solution. The catheter was then placed just inside the urethral meatus, with caution not to overinsert it. The contrast medium was injected through the catheter under controlled pressure to visualise the urinary tract and any fistulous communication, using dynamic fluoroscopy. The operator gently stretches the penis and manually occludes the urethral meatus to prevent contrast medium leakage. The images are reviewed in real time by the performing surgeon. The study is considered negative when the images show no fistula.\u003c/p\u003e \u003cp\u003eData were analysed using descriptive statistics. Categorical variables, including the presence and anatomical level of recto-urinary fistulas, were summarised as frequencies and percentages. The team assessed ACU\u0026rsquo;s diagnostic performance using sensitivity and positive predictive value, referencing intraoperative findings as the standard. Specificity and negative predictive value could not be reliably calculated because no true-negative cases were present in this cohort of patients with high anorectal malformations.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe study successfully identified recto-urinary fistulas in 30 of 35 cases (85.7%; 95% CI: 70.6\u0026ndash;94.1%), while 5 cases (14.3%) showed no visible fistulous communication on ACU. Using intraoperative findings as the reference standard, ACU demonstrated a sensitivity of 85.7% (95% CI: 70.6\u0026ndash;94.1%) and a positive predictive value of 100% (95% CI: 88.4\u0026ndash;100%). Specificity and negative predictive value could not be calculated because there were no true-negative cases in this cohort; all patients had high anorectal malformations.\u003c/p\u003e \u003cp\u003eAmong the visualised cases, 5 (14.3%) had recto-bladder neck fistulas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA),15 (42.9%) had recto-prostatic fistulas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB), and 10 (28.6%) had recto-bulbar fistulas (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC). The team performed colostomies in five cases in which ACU did not demonstrate the fistula, enabling further anatomical assessment and staged repair. In one case, neither the ACU nor the distal colostogram identified the fistula; however, intraoperative PSARP revealed a small rectobulbar fistula.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis study demonstrated that ACU successfully identified recto-urinary fistulas in 85.7% of non-colostomized male neonates with ARMs. This finding supports ACU's role as a valuable primary imaging modality for preoperative planning, providing essential anatomical information without the need for a preliminary colostomy. By defining the level of the recto-urinary fistula, ACU supports the safe selection of candidates for single-stage procedures such as SILAARP and facilitates an appropriate surgical strategy (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA major advantage of ACU is that it can be performed without sedation or general anaesthesia, unlike MRI or cystoscopy. The ACU technique provides real-time visualisation of the urinary tract and fistulous communication, allowing immediate interpretation by the performing surgeon. It is simple to perform, minimally invasive, cost-effective, and readily available in most centres.\u003c/p\u003e \u003cp\u003eIn a previous study with a comparable patient cohort, preoperative fistula level determination achieved the highest diagnostic accuracy (70%), followed by colostogram (66%) and Voiding Cystourethrogram (VCUG) (58%) [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. While none were statistically superior, ACU offers a distinct advantage as a minimally invasive, real-time imaging technique that does not require general anaesthesia, making it suitable for early preoperative evaluation. A 2023 study found that high-pressure distal colostogram achieved greater accuracy than MRI in defining fistula type among males with ARMs after colostomy. It is recommended that VCUG be performed to reduce the risk of false-negative results when no fistula is detected [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, this approach requires a prior colostomy and multiple imaging procedures, which can delay definitive repair. In our study, ACU identified fistulas in 85.7% of cases, outperforming MRI, which correctly detected fistula presence in approximately 76.6% of patients [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. These findings reinforce ACU\u0026rsquo;s value as a practical, first-line diagnostic tool for non-colostomized neonates. MRI remains costly and less accessible in many settings. Initial blind cystoscopy has been shown to miss up to half of fistulas, although a second procedure can identify all fistulas and correctly locate most (80%) [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Despite this, cystoscopy remains invasive, carries a risk of urethral trauma, and may still show discrepancies when compared with intraoperative findings.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAnother preoperative technique, transperineal ultrasound, provides a noninvasive means of assessing fistula anatomy. Still, its accuracy depends heavily on operator skill, patient anatomy, and fistula complexity, often making precise localisation difficult [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. A small study suggested that neonatal perineal ultrasound could identify fistulous tracts and enable one-stage repair in selected male neonates without perineal fistula [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]; however, the limited sample size and reliance on expert radiologic interpretation limit its broader use. In contrast, ACU is straightforward, reproducible, and allows real-time assessment by the surgeon, making it a more practical and widely accessible preoperative tool.\u003c/p\u003e \u003cp\u003eA limitation of this study is the relatively small sample size and the absence of interobserver assessment, which may affect the precision and reproducibility of estimates. Nevertheless, ACU demonstrated consistently high detection rates in this cohort, highlighting its reliability as a primary imaging tool. Despite this, the findings highlight the diagnostic value of ACU as a first-line investigation in non-colostomized male neonates with high anorectal malformations, potentially serving as a practical alternative to more expensive imaging modalities for preoperative fistula localisation before single-stage repair. While comparisons with other modalities, such as MRI, distal colostogram, or cystoscopy, are promising, larger studies are warranted to validate ACU\u0026rsquo;s superior performance across broader populations.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eACU is a reliable, minimally invasive, and readily available technique for preoperative localisation of recto-urinary fistulas in non-colostomized male neonates with high ARM. In our series, it accurately identified the fistula level in most cases, providing crucial anatomical detail for surgical planning while avoiding the risks, costs, and delays associated with colostography or other complex imaging methods. ACU can be safely performed within the first 24 hours of life, allowing early and accurate identification of recto-urinary fistulas. This early anatomical definition supports the safe selection of candidates for single-stage repair. It reinforces ACU\u0026rsquo;s value as a practical first-line diagnostic tool in the management of high anorectal malformations.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eHUMAN ETHICS AND CONSENT TO PARTICIPATE\u003c/h2\u003e \u003cp\u003e The study was approved by the Research Ethics Committee (REC), Faculty of Medicine, Cairo University. Written informed consent was obtained from the parents or legal guardians of all participating neonates prior to enrolment in the study. All procedures were conducted in accordance with the ethical standards of the institutional research committee and with the principles of the Declaration of Helsinki.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFUNDING\u003c/h2\u003e \u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eH.E. and A.F. conceived and designed the study. A.A. collected the clinical and imaging data. A.A. and U.Z. performed the data analysis and interpretation. A.A. and U.Z. prepared the manuscript, figures and illustrations. All authors critically revised the manuscript and approved the final version for submission.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe author wishes to express profound gratitude and deep respect to the late Professor Hesham Elsaket, who served as the main supervisor of this MD thesis entitled in Cairo University.Professor Elsaket\u0026rsquo;s invaluable guidance, exceptional surgical insight, and unwavering academic support were fundamental to the conception, execution, and completion of this work. His dedication to pediatric surgery, commitment to scientific excellence, and mentorship have left a lasting impact on both this research and the author\u0026rsquo;s professional development.His untimely passing during the COVID-19 pandemic is a great loss to the medical and academic community. This work is respectfully dedicated to his memory, in recognition of his enduring contributions and inspirational leadership.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data supporting the findings of this study were generated in the Pediatric Surgery Department at Cairo University and include clinical, imaging, and intraoperative data from neonates with high anorectal malformations. Due to the sensitive nature of patient data and ethical restrictions, the datasets are not publicly available. De-identified data are available from the corresponding author upon reasonable request and with appropriate institutional approval.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePena A (1995) Anorectal malformations. J Japanese Soc Pediatr Surg 31(5):718\u0026ndash;731\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSomme S, Langer JC (2004) Primary versus staged pull-through for the treatment of Hirschsprung disease. Seminars in Pediatric Surgery, vol 13. Elsevier BV, pp 249\u0026ndash;255. 4\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTofft L, Sal\u0026ouml; M, Arnbj\u0026ouml;rnsson E, Stenstr\u0026ouml;m P (2021) Accuracy of pre-operative fistula diagnostics in anorectal malformations. \u003cem\u003eBMC pediatrics\u003c/em\u003e, \u003cem\u003e21\u003c/em\u003e(1), p.283\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBai J, Zhang B, Lin K (2023) Preoperative fistula diagnostics in male anorectal malformations after colostomy: a single-center experience. \u003cem\u003eBMC Medical Imaging\u003c/em\u003e, \u003cem\u003e23\u003c/em\u003e(1), p.139\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGhasi RG, Mittal MK, Bagga D (2018) Anorectal malformations: Role of MRI in preoperative evaluation. Indian J Radiol Imaging 28(02):187\u0026ndash;194\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShojaeian R, Hiradfar M, Taqanaki PB, Ameri L, Mashhadi MP (2023) Evaluating the utility of cystoscopy, distal colostography, and sonography for locating the fistula in patients with anorectal malformation: a case series. Annals Med Surg 85(5):1436\u0026ndash;1441\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaconi G, Greco MT, Asthana AK (2017) Transperineal ultrasound for perianal fistulas and abscesses\u0026ndash;a systematic review and meta-analysis. Ultraschall der Medizin-European J Ultrasound 38(03):265\u0026ndash;272\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGin\u0026eacute; C, Coma A, Garc\u0026iacute;a L, La\u0026iacute;n A, Barber I, Maluje R, L\u0026oacute;pez M (2021) Neonatal Ultrasound for Anorectal Malformations in Male Newborns Without Perineal Fistula: A Good Diagnostic Tool for A Safe One-Staged Surgery. Archives Clin Med Case Rep 5:811\u0026ndash;820\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"egyptian-pediatric-association-gazette","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"epag","sideBox":"Learn more about [Egyptian Pediatric Association Gazette](https://epag.springeropen.com)","snPcode":"43054","submissionUrl":"https://submission.springernature.com/new-submission/43054/3?","title":"Egyptian Pediatric Association Gazette","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-8575330/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8575330/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBACKGROUND\u003c/h2\u003e \u003cp\u003eAccurate preoperative identification of recto-urinary fistulas in male neonates with high anorectal malformations (ARMs) is essential for surgical planning, especially when considering single-stage repair. The ascending cystourethrogram (ACU) provides a simple, minimally invasive approach that eliminates the need for a preliminary colostomy.\u003c/p\u003e\u003ch2\u003eMETHODS\u003c/h2\u003e \u003cp\u003eThis prospective study included 35 male neonates with high ARM who underwent ACU before definitive repair. The presence and level of recto-urinary fistulas are recorded and compared with intraoperative findings. When imaging did not demonstrate the fistula, distal colostrography is performed to confirm the diagnosis.\u003c/p\u003e\u003ch2\u003eRESULTS\u003c/h2\u003e \u003cp\u003eACU identified recto-urinary fistulas in 30 of 35 neonates (85.7%; 95% CI: 70.6\u0026ndash;94.1%). Detected fistulas included recto-bladder neck (14.3%), recto-prostatic (42.9%), and recto-bulbar (28.6%) types. In five cases (14.3%), a fistula was not visualised on ACU; however, distal colostogram confirmed the diagnosis in four. Relative to intraoperative findings, ACU demonstrated a sensitivity of 85.7% and a positive predictive value of 100%.\u003c/p\u003e\u003ch2\u003eCONCLUSION\u003c/h2\u003e \u003cp\u003eACU is a reliable, minimally invasive, and readily available technique for early localisation of recto-urinary fistulas in male neonates with high ARM, demonstrating close correlation with intraoperative findings. It can be safely performed within the first 24 hours of life, enabling prompt anatomical assessment and supporting the appropriate selection of candidates for single-stage repair. These findings reinforce ACU\u0026rsquo;s role as a practical first-line diagnostic tool in the management of high anorectal malformations.\u003c/p\u003e","manuscriptTitle":"Diagnostic Accuracy of Ascending Cystourethrogram for Localising Recto-Urinary Fistulas in Non-Colostomized Male Neonates with High Anorectal Malformations: Cairo University Paediatric Surgery Experience","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-27 10:26:47","doi":"10.21203/rs.3.rs-8575330/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-03T16:16:40+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-25T02:42:11+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-23T21:24:03+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-22T07:59:39+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-19T20:50:40+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"143903417072434840974624777445181661879","date":"2026-01-19T20:38:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"233495939575910619647625189402883183251","date":"2026-01-18T21:06:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"160962600927243288568144359519971412569","date":"2026-01-18T16:28:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"86829979915768011473373230017874276037","date":"2026-01-18T07:24:16+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-17T15:42:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"23003436635525522622886410834225210789","date":"2026-01-17T08:36:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"324208681426285173909351039711810942978","date":"2026-01-16T10:44:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"86578774034924550502127756998800134619","date":"2026-01-16T07:42:15+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-16T05:27:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-16T04:46:21+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-16T04:44:38+00:00","index":"","fulltext":""},{"type":"submitted","content":"Egyptian Pediatric Association Gazette","date":"2026-01-11T18:28:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"egyptian-pediatric-association-gazette","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"epag","sideBox":"Learn more about [Egyptian Pediatric Association Gazette](https://epag.springeropen.com)","snPcode":"43054","submissionUrl":"https://submission.springernature.com/new-submission/43054/3?","title":"Egyptian Pediatric Association Gazette","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4afeb785-acd8-4bbb-b059-2fc0e37d9dc3","owner":[],"postedDate":"January 27th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-16T16:12:16+00:00","versionOfRecord":{"articleIdentity":"rs-8575330","link":"https://doi.org/10.1186/s43054-026-00527-2","journal":{"identity":"egyptian-pediatric-association-gazette","isVorOnly":false,"title":"Egyptian Pediatric Association Gazette"},"publishedOn":"2026-03-09 15:58:58","publishedOnDateReadable":"March 9th, 2026"},"versionCreatedAt":"2026-01-27 10:26:47","video":"","vorDoi":"10.1186/s43054-026-00527-2","vorDoiUrl":"https://doi.org/10.1186/s43054-026-00527-2","workflowStages":[]},"version":"v1","identity":"rs-8575330","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8575330","identity":"rs-8575330","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}