Anovestibular fistula versus other subtypes in female patients with low-type anorectal malformation: Differential patterns in defecation function improvement and associated anomalies at a single institution

Anovestibular fistula versus other subtypes in female patients with low-type anorectal malformation: Differential patterns in defecation function improvement and associated anomalies at a single institution | 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 Anovestibular fistula versus other subtypes in female patients with low-type anorectal malformation: Differential patterns in defecation function improvement and associated anomalies at a single institution Toshio Harumatsu, Ayaka Nagano, Koshiro Sugita, Yumiko Tabata, and 12 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8780616/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Feb, 2026 Read the published version in Pediatric Surgery International → Version 1 posted 7 You are reading this latest preprint version Abstract Purpose To investigate associated anomalies and the postoperative defecation function in female patients with low-type anorectal malformations (ARMs), focusing on comparing anovestibular fistula (AVF) with other subtypes. Methods Patient data were collected between 1984 and 2021. Eighty-seven female patients with low-type ARMs were enrolled after excluding one undetermined case. Associated anomalies, operative procedures, and the long-term defecation function were analyzed and compared between the AVF and non-AVF groups. Results AVF was the most common subtype (52.9%), followed by anocutaneous fistula (21.8%), covered anal stenosis (11.5%), anovulvar fistula (10.3%), and covered anal complete (3.4%). Upper urinary tract anomalies and VACTERL association were significantly more frequent in AVF (17.4% and 13.0%) than in non-AVF. Specific associations were identified: trisomy 21 with covered anal complete (100%), perineal groove with anocutaneous fistula (10.5%), and MRKH syndrome with AVF (2.2%). Chronologically, non-AVF low-type ARMs achieved "excellent" evacuation scores at 6 years, whereas AVF patients typically achieved this by 9 years. Individual defecation parameters reached full scores by 7 years in all subtypes except AVF, where constipation persisted beyond 11 years. Conclusion The postoperative defecation function in female patients with low-type ARMs demonstrates differential improvement patterns, with AVF requiring extended management until at least 9 years. low-type anorectal malformation defecation function female associated anomaly Figures Figure 1 Figure 2 Introduction Low-type anorectal malformations (ARMs) in females, including anovestibular fistula (AVF), anovulvar fistula, and anocutaneous fistula, are commonly treated with anorectoplasty without colostomy [ 1 ]. Previous studies have reported that the postoperative defecation function in patients with low-type ARM improves over time, with most achieving satisfactory outcomes [ 2 , 3 ]. Our research group previously investigated the postoperative defecation function specifically in AVF patients, comparing the outcomes of anal transplantation and anterior sagittal anorectoplasty [ 4 ]. AVF is the most common type of low-type ARM in female patients and represents the most anteriorly located fistula opening. We hypothesized that comparing AVF with other non-AVF subtypes would provide better insight into the characteristics of low-type ARMs. Despite this important anatomical distinction, few studies have compared associated anomalies, surgical management, and long-term defecatory function between AVF and non-AVF groups in female patients with low-type ARMs. Furthermore, chronological improvement patterns in the defecation function according to specific ARM subtypes have not been comprehensively evaluated. This study aimed to compare AVF and non-AVF groups in female patients with low-type ARMs and analyze associated anomalies, surgical management, and long-term defecation function outcomes. Materials and methods 1.1. Study population We retrospectively reviewed all patients who underwent definitive surgery at our institution between 1984 and 2021. The inclusion criteria were as follows: female patients with low-type ARMs including anovestibular fistula, anovulvar fistula, anocutaneous fistula, covered anal stenosis, and covered anal complete who underwent definitive surgery at our institution between 1984 and 2021, with available medical records documenting ARM subtype classification. The exclusion criteria were as follows: patients with undetermined ARM subtype and patients with incomplete medical records precluding accurate classification. For the analysis of long-term defecation function, only patients who had reached at least 3 years of age with available follow-up data were included. Eighty-eight female patients with low-type ARMs who underwent definitive surgery at our institution were enrolled in this study. Low-type ARMs were defined as follows: anovestibular fistula (AVF), anovulvar fistula, anocutaneous fistula, covered anal stenosis, and covered anal complete. One patient with an undetermined ARM type was excluded from the analysis, resulting in a final study population of 87 patients. 1.2. Surgical procedures The operative procedures for anorectoplasty were classified as anal transplantation (AT), anterior sagittal anorectoplasty (ASARP), cutback, and other procedures. The surgical approach was determined according to the ARM subtype following our institutional protocol. For anovestibular fistula, AT was the primary procedure. For anocutaneous fistula and anovulvar fistula, either cutback procedure or ASARP was selected based on the fistula location and the distance to the sphincter complex. Covered anal stenosis was primarily treated with AT when significant ectopic positioning was present, while minor cutback procedures were performed for cases with minimal displacement. Covered anal complete required AT. The specific operative procedure for each patient was ultimately determined by the attending pediatric surgeon and surgical team at the timing of definitive surgery, based on these criteria and individual anatomical considerations. 1.3. Data collection The patients' background characteristics, types of ARMs, associated anomalies, operative procedures, postoperative management, and long-term defecation function were reviewed based on their medical records and were retrospectively analyzed. Associated anomalies were categorized into genitourinary system anomalies (upper urinary tract anomalies and lower genital tract anomalies), vertebral anomalies, cardiac anomalies, and chromosomal/syndromic conditions and were analyzed for each type of ARM. Postoperative management parameters, including the duration of glycerin enema treatment and age at achieving "excellent" evacuation scores, were also collected and analyzed. 1.4. Evaluation of the defecation function Follow-up data of patients who were at least three years of age were retrospectively analyzed. The defecation function was evaluated at 3, 5, 7, 9, and 11 years of age using the evacuation score (ES) of the Japanese Study Group of Anorectal Anomalies [ 4 ]. The ES is based on four parameters: (1) urge to defecate, (2) constipation, (3) incontinence, and (4) soiling. The ES was assessed by pediatric surgeons during routine outpatient follow-up visits through structured interviews with the parents or caregivers. All four parameters (urge to defecate, constipation, incontinence, and soiling) were evaluated based on parental reports of the child's defecation patterns and continence status. Constipation refers to the retention of stool requiring intervention. Incontinence refers to the leakage of stool. Soiling refers to slight soiling of the underwear. The total ES was calculated by adding the urge to defecate and soiling scores to a lower score for either constipation or incontinence. The maximum total score was 8 points, which indicates an excellent defecation function. Clinical stratification was evaluated according to the total ES as follows: 0–4 points, poor; 5–6 points, good; 7–8 points, excellent. 1.5. Statistical analyses Categorical variables were compared using Fisher's exact test or chi-square test, as appropriate. Continuous variables were compared using the Mann-Whitney U test for non-parametric data or Student's t-test for parametric data. Scores for each process measure were analyzed using repeated-measures analysis of variance to evaluate changes over time. Data are expressed as the mean ± standard deviation or as numbers and percentages. Statistical significance was set p < 0.05. All statistical analyses were performed using EZR (Saitama Medical Center, Jichi Medical University, Saitama, Japan), a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria). More precisely, it is a modified version of the R commander designed to add statistical functions frequently used in biostatistics [ 5 ]. Results 2.1. Patient characteristics and ARM subtype distribution Among the 87 patients with confirmed ARM subtypes, 46 (52.9%) had AVF, representing the largest subgroup. The non-AVF group consisted of 41 patients (47.1%), including 19 patients (21.8%) with anocutaneous fistula, 10 patients (11.5%) with covered anal stenosis, 9 patients (10.3%) with anovulvar fistula, and 3 patients (3.4%) with covered anal complete (Table 1). 2.2. Comparison of associated anomalies between AVF and non-AVF groups Table 2 shows the distribution of associated anomalies between the two groups. Upper urinary tract anomalies were significantly more frequent in the AVF group than in the non-AVF group (17.4% vs 2.4%, p =0.03). VACTERL association was observed exclusively in the AVF group, affecting six patients (13.0%), while no cases were found in the non-AVF group ( p =0.03). No significant differences were observed in other anomaly categories, including lower genital tract anomalies, vertebral anomalies, and total cardiac anomalies, between the two groups. 2.3. Clinical management parameters and outcomes Significant differences were observed in the operative procedures between the AVF and non-AVF groups ( p <0.001) (Table 3). Anal transplantation was the predominant procedure in the AVF group (82.6%) compared to the non-AVF group (22.0%, p <0.001). Conversely, cutback procedures were performed exclusively in the non-AVF group (36.6%) and were not performed in any AVF group ( p <0.001). Other procedures were also significantly more common in the non-AVF group (31.7%) than in the AVF group (0%; p <0.001). The glycerin enema treatment period was significantly longer in the AVF group compared to the non-AVF group (4.1±3.9 years vs. 2.2±2.8 years, p =0.013). The age at which patients achieved an "excellent" score showed no significant difference between groups (5.1±2.3 years for AVF vs. 4.3±1.4 years for non-AVF, p =0.14). 2.4. Detailed analysis by individual ARM subtypes Table 4 shows the characteristics of each ARM subtype. All three cases of covered anal complete were associated with trisomy 21 (100%). VACTERL association was found in six cases (13.0%) of AVF patients, while no cases were observed in other subtypes. The perineal groove was identified in 2 cases (10.5%) of anocutaneous fistula. The mean age at operation varied among subtypes, with covered anal stenosis showing the latest intervention at 8.3±7.9 months, while other subtypes underwent surgery at approximately 5.8-5.9 months. The treatment period with glycerin enema was longest for AVF patients (4.1±3.9 years), followed by anovulvar fistula patients (3.2±3.2 years). 2.5. Postoperative defecation function over time Figure 1 shows the chronological changes in the total evacuation score for each ARM type. The total evacuation score progressively improved with age for all ARM types. Low-type ARMs, excluding AVF, had "excellent" scores (7-8 points) at approximately 6 years of age, while AVF patients typically achieved "excellent" scores at 9 years of age. 2.6. Analysis of individual defecation parameters Figure 2 shows the detailed progression of each defecation parameter. The urge to defecate scores gradually improved and reached maximum scores by 7 years of age in all ARM types, except covered anal stenosis (Figure 2a). Constipation scores showed slower improvement in AVF patients, failing to reach maximum scores even at 11 years of age, while other ARM types achieved full scores by 7 years of age (Figure 2b). The incontinence scores demonstrated similar improvement patterns across all ARM types, reaching satisfactory levels by 7 years of age (Figure 2c). Soiling scores for anovulvar fistula remained consistently lower (1.0-1.5 points) in comparison to other subtypes, while other ARM types showed gradual improvement with age (Figure 2d). Discussion In the present study, we retrospectively reviewed our single institution's experience with female patients with low-type ARMs and compared associated anomalies, surgical management, and long-term defecation function between the AVF and non-AVF groups. The major findings were as follows: (1) upper urinary tract anomalies and VACTERL association were significantly more frequent in the AVF group; (2) anal transplantation was the predominant surgical procedure in AVF patients, whereas cutback procedures were performed exclusively in the non-AVF group; (3) low-type ARMs excluding AVF reached "excellent" evacuation scores at approximately 6 years of age, while AVF patients typically achieved "excellent" scores at 9 years of age; (4) specific associations were identified, including trisomy 21 with covered anal complete, perineal groove with anocutaneous fistula, and MRKH syndrome with AVF patients; and (5) glycerin enema treatment periods were significantly longer in AVF patients, and constipation scores showed slower improvement compared to other subtypes. The significant differences in the associated anomalies between the AVF and non-AVF groups highlight the distinct clinical nature of each subtype. The exclusive occurrence of VACTERL association in the AVF group suggests that AVF represents a more complex developmental abnormality within the low-type ARM spectrum. The association between MRKH syndrome and low-type ARMs has been increasingly recognized. Levitt et al. reported gynecologic anomalies in patients with vestibular fistulas [6]. However, the lower frequency observed in our current study may reflect insufficient evaluation of vaginal abnormalities in the earlier periods of our institutional experience. Our study identified notable associations specific to individual ARM subtypes, with important diagnostic and management implications. The association between the perineal groove and anocutaneous fistula represents an under-recognized relationship [7]. The perineal groove is frequently misdiagnosed as an anal fissure or suspected sexual abuse [8], making accurate identification crucial. Surgical excision during anorectoplasty is recommended [9]. The complete association between covered anal complete and trisomy 21 in our series aligns with established literature demonstrating strong relationships between Down syndrome and anorectal malformations without fistula. Endo et al. demonstrated that the incidence of Down syndrome in deformities without fistulas was significantly higher than that in deformities with fistulas [10]. Bischoff and Sarkar et al. reported similar strong associations, emphasizing the importance of chromosomal evaluation in patients with covered anal complete [11,12]. Regarding functional outcomes, the chronological improvement patterns observed in our study have significant implications for long-term management. The delayed functional improvement in AVF patients, reaching "excellent" scores three years later than other subtypes, necessitates extended follow-up and specialized care coordination. This delayed improvement may be attributed to the anatomical complexity of the AVF, particularly the higher confluence points between the rectum and the vagina. The prolonged requirement for bowel management was evidenced by significantly longer glycerin enema treatment periods and persistent constipation challenges that did not reach full scores, even at 11 years of age. Based on our findings, we recommend comprehensive gynecological evaluation for all female patients with low-type ARMs, particularly those with AVF, as part of the preoperative assessment. This should include a systematic evaluation for MRKH syndrome, even in the absence of external genital abnormalities, as the external appearance is typically normal [13]. Early identification enables appropriate family counseling and coordinated surgical planning that addresses both immediate functional needs and long-term reproductive considerations. For patients with covered anal complete, clinicians should maintain a high index of suspicion for trisomy 21 and modify diagnostic approaches accordingly. Ultrasonographic evaluation may be particularly valuable in these patients, as traditional invertography has been shown to have a sensitivity of only 27% (relative to 86% for ultrasonography) in determining the bowel-skin distance [14]. Recognition of the perineal groove in patients with ANF is important for comprehensive surgical planning and the prevention of long-term complications. Considering the characteristics of each disease subtype, intensive outpatient defecation management should be maintained until at least 7 years of age for most subtypes, with extended follow-up recommended for AVF patients due to their delayed functional improvement patterns. The association between low-type ARMs and specific congenital anomalies requires specialized expertise and coordinated multidisciplinary care. Our findings have important implications for clinical counseling of families with AVF patients. First, families should be counseled that improvement in defecation function may continue over an extended period, with some patients requiring up to 9 years to achieve optimal outcomes. Second, based on previous reports showing that constipation-related overflow incontinence often improves during adolescence in ARM patients [15], families should be encouraged to maintain consistent bowel management programs throughout childhood. Third, given the prolonged timeline and the potential psychosocial impact of fecal incontinence on social and emotional functioning [16], multidisciplinary support including psychological counseling may benefit these patients and their families. Finally, early initiation of bowel management programs [17] and regular follow-up are essential to optimize long-term functional outcomes in AVF patients. This study had several limitations. First, as a single-center retrospective study spanning 37 years, treatment strategies and evaluation methods may have varied over time, potentially affecting the outcomes. Second, the small sample sizes in some ARM subtypes, particularly covered anal complete, limits statistical power. Finally, a multivariate analysis was not performed to adjust for potential confounding factors such as associated anomalies and surgical techniques, which may influence defecation function outcomes. Conclusion We investigated the detailed characteristics and chronological changes in the postoperative defecation function in female patients with low-type ARMs. Our study demonstrated significant differences between the AVF and non-AVF subtypes in terms of associated anomalies, surgical management, and functional outcomes. The identification of specific associations, including MRKH syndrome with AVF, perineal groove with anocutaneous fistula, and trisomy 21 with covered anal complete, emphasizes the importance of subtype-specific evaluation and management approaches. The delayed functional improvement observed in patients with AVF necessitates extended follow-up and specialized care coordination. Declarations Author contributions H.T., N.A., and S.K. wrote the manuscript. T.Y., O.S., and Y.K. prepared the tables and reviewed the literature. T.Y., N.N., T.Y., K.C., M.M., Y.K., Y.W., and N.A. collected the data based on medical records. K.T., T.M., and K.T. provided conceptual advice. I.S. critically reviewed the manuscript and supervised all collected data. All authors have reviewed the manuscript. Data availability The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request. Conflict of interest The authors declare no conflicts of interest in association with the present study. Acknowledgments We thank Brian Quinn for his comments and assistance with this manuscript. This study was supported by a research grant from The Mother and Child Health Foundation, a research grant from the Kawano Masanori Memorial Public Interest Incorporated Foundation for Promotion of Pediatrics, and Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS: 25K22713, 25K11062, 25K11154, 25K11847, 25K11871, 24K06285, 24K15813, 23K20735, 23K07281, 23K08031, 23K08052, 23K11934). References Shirota C, Suzuki K, Uchida H, Kawashima H, Hinoki A, Tainaka T, Sumida W, Murase N, Oshima K, Chiba K, Makita S, Tanaka Y (2018) Investigation of the feasibility and safety of single-stage anorectoplasty in neonates with anovestibular fistula. Pediatr Surg Int 34(10):1117–1120 Wakhlu A, Kureel SN, Tandon RK, Wakhlu AK (2009) Long-term results of anterior sagittal anorectoplasty for the treatment of vestibular fistula. J Pediatr Surg 44(10):1913–1919 Elrouby A, Waheeb S, Koraitim A (2020) Anterior sagittal anorectoplasty as a technique for the repair of female anorectal malformations: A twenty two-years-single-center experience. J Pediatr Surg 55(3):393–396 Nagano A, Harumatsu T, Sugita K, Iwamoto Y, Ogata M, Takada L, Nishida N, Kedoin C, Murakami M, Yano K, Onishi S, Yamada K, Yamada W, Kawano T, Muto M, Kaji T, Ieiri S (2023) Change over time in the postoperative defecation function in female patients with anovestibular fistula at a single institution: focus on the comparison of anal transposition with anterior sagittal anorectoplasty. Pediatr Surg Int 39(1):266 Kanda Y (2013) Investigation of the freely available easy-to-use software 'EZR' for medical statistics. Bone Marrow Transpl 48(3):452–458 Levitt MA, Bischoff A, Breech L, Pena A (2009) Rectovestibular fistula–rarely recognized associated gynecologic anomalies. J Pediatr Surg 44(6):1261–1267 discussion 1267 Samuk I, Amerstorfer EE, Fanjul M, Iacobelli BD, Lisi G, Midrio P, Morandi A, Schmiedeke E, Stenstrom P, Sleeboom C (2020) Perineal Groove: An Anorectal Malformation Network, Consortium Study. J Pediatr 222:207–212 Cheng H, Wang Z, Zhao Q, Zhu H, Xu T (2018) Perineal Groove: Report of Two Cases and Review of the Literature. Front Pediatr 6:227 Ihn K, Na Y, Ho IG, Oh JT (2020) Clinical characteristics and conservative treatment of perineal groove. J Pediatr Surg 55(8):1507–1510 Endo M, Hayashi A, Ishihara M, Maie M, Nagasaki A, Nishi T, Saeki M (1999) Analysis of 1,992 patients with anorectal malformations over the past two decades in Japan. Steering Committee of Japanese Study Group of Anorectal Anomalies. J Pediatr Surg 34(3):435–441 Bischoff A, Frischer J, Dickie BH, Peña A (2014) Anorectal malformation without fistula: a defect with unique characteristics. Pediatr Surg Int 30(8):763–766 Sarkar A, Al Shanafey S, Mourad M, Abudan A (2018) No-fistula vs. fistula type anorectal malformation: Outcome comparative study. J Pediatr Surg 53(9):1734–1736 Breech L (2010) Gynecologic concerns in patients with anorectal malformations. Semin Pediatr Surg 19(2):139–145 Niedzielski JK (2005) Invertography versus ultrasonography and distal colostography for the determination of bowel-skin distance in children with anorectal malformations. Eur J Pediatr Surg 15(4):262–267 Rintala RJ, Lindahl HG (2001) Fecal continence in patients having undergone posterior sagittal anorectoplasty procedure for a high anorectal malformation improves at adolescence, as constipation disappears. J Pediatr Surg 36(8):1218–1221 Grano C, Aminoff D, Lucidi F, Violani C (2012) Long-term disease-specific quality of life in children and adolescent patients with ARM. J Pediatr Surg 47(7):1317–1322 Pena A, Guardino K, Tovilla JM, Levitt MA, Rodriguez G, Torres R (1998) Bowel management for fecal incontinence in patients with anorectal malformations. J Pediatr Surg 33(1):133–137 Tables Tables are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files HarumatsuTetalTable1forPSIWOFAPS2025Issue.docx HarumatsuTetalTable2forPSIWOFAPS2025Issue.docx HarumatsuTetalTable3forPSIWOFAPS2025Issue.docx HarumatsuTetalTable4forPSIWOFAPS2025Issue.docx Cite Share Download PDF Status: Published Journal Publication published 21 Feb, 2026 Read the published version in Pediatric Surgery International → Version 1 posted Editorial decision: Accepted 06 Feb, 2026 Reviews received at journal 06 Feb, 2026 Reviewers agreed at journal 06 Feb, 2026 Reviewers invited by journal 06 Feb, 2026 Editor assigned by journal 05 Feb, 2026 Submission checks completed at journal 05 Feb, 2026 First submitted to journal 03 Feb, 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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01:24:02","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8780616/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8780616/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00383-026-06329-2","type":"published","date":"2026-02-21T15:57:10+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":102746038,"identity":"1abecef3-c0c6-488e-9844-1014df98fa0a","added_by":"auto","created_at":"2026-02-16 08:55:21","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":562035,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eTotal evacuation score according to the type of ARMs\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eARM, anorectal malformation; y.o., years old.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8780616/v1/e1e791585b701eb9a99b7557.jpg"},{"id":102438900,"identity":"f3356805-1c45-4ebe-8907-c17388dd00b0","added_by":"auto","created_at":"2026-02-11 16:37:16","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":755127,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe comparison of detailed scores according to the type of ARMs\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(a) Urge to defecate\u003c/p\u003e\n\u003cp\u003e(b) Constipation\u003c/p\u003e\n\u003cp\u003e(c) Incontinence\u003c/p\u003e\n\u003cp\u003e(d) Soiling\u003c/p\u003e\n\u003cp\u003eARM, anorectal malformation; y.o., years old.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8780616/v1/495950818a98062557fa9066.jpg"},{"id":103251023,"identity":"38127d9d-4059-4fdb-8e65-339bf740c3c4","added_by":"auto","created_at":"2026-02-23 16:01:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2056461,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8780616/v1/904412be-03c3-4139-b9b0-44043f9b6098.pdf"},{"id":102438904,"identity":"aecaa588-cfbe-4a97-87f4-b72f213e8c3d","added_by":"auto","created_at":"2026-02-11 16:37:16","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":19628,"visible":true,"origin":"","legend":"","description":"","filename":"HarumatsuTetalTable1forPSIWOFAPS2025Issue.docx","url":"https://assets-eu.researchsquare.com/files/rs-8780616/v1/5ae83db00a60e5cc3b1863a9.docx"},{"id":102745801,"identity":"c6d87bba-ff5d-4ed8-ad49-521d366d944b","added_by":"auto","created_at":"2026-02-16 08:54:05","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":21299,"visible":true,"origin":"","legend":"","description":"","filename":"HarumatsuTetalTable2forPSIWOFAPS2025Issue.docx","url":"https://assets-eu.researchsquare.com/files/rs-8780616/v1/cb62608af51cdb1a4eafbf79.docx"},{"id":102438902,"identity":"c9cf23b1-c469-4b6a-8040-32c859d96591","added_by":"auto","created_at":"2026-02-11 16:37:16","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":20529,"visible":true,"origin":"","legend":"","description":"","filename":"HarumatsuTetalTable3forPSIWOFAPS2025Issue.docx","url":"https://assets-eu.researchsquare.com/files/rs-8780616/v1/edeecd5d0989ad6ee4c74cc7.docx"},{"id":102745956,"identity":"8f157fc1-e7eb-4cad-a75c-75c1d3fd1e2c","added_by":"auto","created_at":"2026-02-16 08:54:55","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":21562,"visible":true,"origin":"","legend":"","description":"","filename":"HarumatsuTetalTable4forPSIWOFAPS2025Issue.docx","url":"https://assets-eu.researchsquare.com/files/rs-8780616/v1/5ab533f10c9b9118c87c2c1f.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Anovestibular fistula versus other subtypes in female patients with low-type anorectal malformation: Differential patterns in defecation function improvement and associated anomalies at a single institution","fulltext":[{"header":"Introduction","content":"\u003cp\u003eLow-type anorectal malformations (ARMs) in females, including anovestibular fistula (AVF), anovulvar fistula, and anocutaneous fistula, are commonly treated with anorectoplasty without colostomy [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Previous studies have reported that the postoperative defecation function in patients with low-type ARM improves over time, with most achieving satisfactory outcomes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Our research group previously investigated the postoperative defecation function specifically in AVF patients, comparing the outcomes of anal transplantation and anterior sagittal anorectoplasty [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. AVF is the most common type of low-type ARM in female patients and represents the most anteriorly located fistula opening. We hypothesized that comparing AVF with other non-AVF subtypes would provide better insight into the characteristics of low-type ARMs.\u003c/p\u003e \u003cp\u003eDespite this important anatomical distinction, few studies have compared associated anomalies, surgical management, and long-term defecatory function between AVF and non-AVF groups in female patients with low-type ARMs. Furthermore, chronological improvement patterns in the defecation function according to specific ARM subtypes have not been comprehensively evaluated.\u003c/p\u003e \u003cp\u003eThis study aimed to compare AVF and non-AVF groups in female patients with low-type ARMs and analyze associated anomalies, surgical management, and long-term defecation function outcomes.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e1.1. Study population\u003c/h2\u003e \u003cp\u003e We retrospectively reviewed all patients who underwent definitive surgery at our institution between 1984 and 2021. The inclusion criteria were as follows: female patients with low-type ARMs including anovestibular fistula, anovulvar fistula, anocutaneous fistula, covered anal stenosis, and covered anal complete who underwent definitive surgery at our institution between 1984 and 2021, with available medical records documenting ARM subtype classification. The exclusion criteria were as follows: patients with undetermined ARM subtype and patients with incomplete medical records precluding accurate classification. For the analysis of long-term defecation function, only patients who had reached at least 3 years of age with available follow-up data were included.\u003c/p\u003e \u003cp\u003eEighty-eight female patients with low-type ARMs who underwent definitive surgery at our institution were enrolled in this study. Low-type ARMs were defined as follows: anovestibular fistula (AVF), anovulvar fistula, anocutaneous fistula, covered anal stenosis, and covered anal complete. One patient with an undetermined ARM type was excluded from the analysis, resulting in a final study population of 87 patients.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e1.2. Surgical procedures\u003c/h2\u003e \u003cp\u003eThe operative procedures for anorectoplasty were classified as anal transplantation (AT), anterior sagittal anorectoplasty (ASARP), cutback, and other procedures. The surgical approach was determined according to the ARM subtype following our institutional protocol. For anovestibular fistula, AT was the primary procedure. For anocutaneous fistula and anovulvar fistula, either cutback procedure or ASARP was selected based on the fistula location and the distance to the sphincter complex. Covered anal stenosis was primarily treated with AT when significant ectopic positioning was present, while minor cutback procedures were performed for cases with minimal displacement. Covered anal complete required AT. The specific operative procedure for each patient was ultimately determined by the attending pediatric surgeon and surgical team at the timing of definitive surgery, based on these criteria and individual anatomical considerations.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e1.3. Data collection\u003c/h2\u003e \u003cp\u003eThe patients' background characteristics, types of ARMs, associated anomalies, operative procedures, postoperative management, and long-term defecation function were reviewed based on their medical records and were retrospectively analyzed. Associated anomalies were categorized into genitourinary system anomalies (upper urinary tract anomalies and lower genital tract anomalies), vertebral anomalies, cardiac anomalies, and chromosomal/syndromic conditions and were analyzed for each type of ARM.\u003c/p\u003e \u003cp\u003ePostoperative management parameters, including the duration of glycerin enema treatment and age at achieving \"excellent\" evacuation scores, were also collected and analyzed.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e\u003cb\u003e1.4. Evaluation of the defecation function\u003c/b\u003e\u003c/h2\u003e \u003cp\u003eFollow-up data of patients who were at least three years of age were retrospectively analyzed. The defecation function was evaluated at 3, 5, 7, 9, and 11 years of age using the evacuation score (ES) of the Japanese Study Group of Anorectal Anomalies [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The ES is based on four parameters: (1) urge to defecate, (2) constipation, (3) incontinence, and (4) soiling. The ES was assessed by pediatric surgeons during routine outpatient follow-up visits through structured interviews with the parents or caregivers. All four parameters (urge to defecate, constipation, incontinence, and soiling) were evaluated based on parental reports of the child's defecation patterns and continence status.\u003c/p\u003e \u003cp\u003eConstipation refers to the retention of stool requiring intervention. Incontinence refers to the leakage of stool. Soiling refers to slight soiling of the underwear. The total ES was calculated by adding the urge to defecate and soiling scores to a lower score for either constipation or incontinence. The maximum total score was 8 points, which indicates an excellent defecation function. Clinical stratification was evaluated according to the total ES as follows: 0\u0026ndash;4 points, poor; 5\u0026ndash;6 points, good; 7\u0026ndash;8 points, excellent.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e1.5. Statistical analyses\u003c/h2\u003e \u003cp\u003eCategorical variables were compared using Fisher's exact test or chi-square test, as appropriate. Continuous variables were compared using the Mann-Whitney U test for non-parametric data or Student's t-test for parametric data. Scores for each process measure were analyzed using repeated-measures analysis of variance to evaluate changes over time. Data are expressed as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation or as numbers and percentages. Statistical significance was set \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003cp\u003eAll statistical analyses were performed using EZR (Saitama Medical Center, Jichi Medical University, Saitama, Japan), a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria). More precisely, it is a modified version of the R commander designed to add statistical functions frequently used in biostatistics [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.1. Patient characteristics and ARM subtype distribution\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Among the 87 patients with confirmed ARM subtypes, 46 (52.9%) had AVF, representing the largest subgroup. The non-AVF group consisted of 41 patients (47.1%), including 19 patients (21.8%) with anocutaneous fistula, 10 patients (11.5%) with covered anal stenosis, 9 patients (10.3%) with anovulvar fistula, and 3 patients (3.4%) with covered anal complete (Table 1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.2. Comparison of associated anomalies between AVF and non-AVF groups\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Table 2 shows the distribution of associated anomalies between the two groups. Upper urinary tract anomalies were significantly more frequent in the AVF group than in the non-AVF group (17.4% vs 2.4%, \u003cem\u003ep\u003c/em\u003e=0.03). VACTERL association was observed exclusively in the AVF group, affecting six patients (13.0%), while no cases were found in the non-AVF group (\u003cem\u003ep\u003c/em\u003e=0.03). No significant differences were observed in other anomaly categories, including lower genital tract anomalies, vertebral anomalies, and total cardiac anomalies, between the two groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.3. Clinical management parameters and outcomes\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Significant differences were observed in the operative procedures between the AVF and non-AVF groups (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.001) (Table 3). Anal transplantation was the predominant procedure in the AVF group (82.6%) compared to the non-AVF group (22.0%, \u003cem\u003ep\u003c/em\u003e\u0026lt;0.001). Conversely, cutback procedures were performed exclusively in the non-AVF group (36.6%) and\u0026nbsp;were not performed in any AVF\u0026nbsp;group (\u003cem\u003ep\u003c/em\u003e\u0026lt;0.001). Other procedures were also significantly more common in the non-AVF group (31.7%) than in the AVF group (0%; \u003cem\u003ep\u003c/em\u003e\u0026lt;0.001).\u003c/p\u003e\n\u003cp\u003eThe glycerin enema treatment period was significantly longer in the AVF group compared to the non-AVF group (4.1\u0026plusmn;3.9 years vs. 2.2\u0026plusmn;2.8 years, \u003cem\u003ep\u003c/em\u003e=0.013). The age at which patients achieved an \u0026quot;excellent\u0026quot; score showed no significant difference between groups (5.1\u0026plusmn;2.3 years for AVF vs. 4.3\u0026plusmn;1.4 years for non-AVF, \u003cem\u003ep\u003c/em\u003e=0.14).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.4. Detailed analysis by individual ARM subtypes\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Table 4 shows the characteristics of each ARM subtype. All three cases of covered anal complete were associated with trisomy 21 (100%). VACTERL association was found in six cases (13.0%) of AVF patients, while no cases were observed in other subtypes. The perineal groove was identified in 2 cases (10.5%) of anocutaneous fistula.\u003c/p\u003e\n\u003cp\u003eThe mean age at operation varied among subtypes, with covered anal stenosis showing the latest intervention at 8.3\u0026plusmn;7.9 months, while other subtypes underwent surgery at approximately 5.8-5.9 months. The treatment period with glycerin enema was longest for AVF patients (4.1\u0026plusmn;3.9 years), followed by anovulvar fistula patients (3.2\u0026plusmn;3.2 years).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003e\u003cem\u003e2.5. Postoperative defecation function over time\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFigure 1 shows the chronological changes in\u0026nbsp;the total evacuation score\u0026nbsp;for each ARM type. The total evacuation score progressively\u0026nbsp;improved with age\u0026nbsp;for all ARM types. Low-type ARMs, excluding AVF, had \u0026quot;excellent\u0026quot; scores (7-8 points) at approximately 6 years of age, while AVF patients typically achieved \u0026quot;excellent\u0026quot; scores at 9 years of age.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e2.6. Analysis of individual defecation parameters\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Figure 2 shows the detailed progression of each defecation parameter. The urge to defecate scores gradually improved and reached maximum scores by 7 years of age in all ARM types, except covered anal stenosis (Figure 2a). Constipation scores showed slower improvement in AVF patients, failing to reach maximum scores even at 11 years of age, while other ARM types achieved full scores by 7 years of age (Figure 2b). The incontinence scores demonstrated similar improvement patterns across all ARM types, reaching satisfactory levels by 7 years of age (Figure 2c). Soiling scores for anovulvar fistula remained consistently lower (1.0-1.5 points) in comparison to other subtypes, while other ARM types showed gradual improvement with age (Figure 2d).\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn the present study, we retrospectively reviewed our single institution's experience with female patients with low-type ARMs and compared associated anomalies, surgical management, and long-term defecation function between the AVF and non-AVF groups. The major findings were as follows: (1) upper urinary tract anomalies and VACTERL association were significantly more frequent in the AVF group; (2) anal transplantation was the predominant surgical procedure in AVF patients, whereas cutback procedures were performed exclusively in the non-AVF group; (3) low-type ARMs excluding AVF reached \"excellent\" evacuation scores at approximately 6 years of age, while AVF patients typically achieved \"excellent\" scores at 9 years of age; (4) specific associations were identified, including trisomy 21 with covered anal complete, perineal groove with anocutaneous fistula, and MRKH syndrome with AVF patients; and (5) glycerin enema treatment periods were significantly longer in AVF patients, and constipation scores showed slower improvement compared to other subtypes.\u003c/p\u003e\n\u003cp\u003eThe significant differences in the associated anomalies between the AVF and non-AVF groups highlight the distinct clinical nature of each subtype. The exclusive occurrence of VACTERL association in the AVF group suggests that AVF represents a more complex developmental abnormality within the low-type ARM spectrum. The association between MRKH syndrome and low-type ARMs has been increasingly recognized. Levitt et al. reported gynecologic anomalies in patients with vestibular fistulas [6]. However, the lower frequency observed in our current study may reflect insufficient evaluation of vaginal abnormalities in the earlier periods of our institutional experience.\u003c/p\u003e\n\u003cp\u003eOur study identified notable associations specific to individual ARM subtypes, with important diagnostic and management implications. The association between the perineal groove and anocutaneous fistula represents an under-recognized relationship [7]. The perineal groove is frequently misdiagnosed as an anal fissure or suspected sexual abuse [8], making accurate identification crucial. Surgical excision during anorectoplasty is recommended [9].\u003c/p\u003e\n\u003cp\u003eThe complete association between covered anal complete and trisomy 21 in our series aligns with established literature demonstrating strong relationships between Down syndrome and anorectal malformations without fistula. Endo et al. demonstrated that the incidence of Down syndrome in deformities without fistulas was significantly higher than that in deformities with fistulas [10]. Bischoff and Sarkar et al. reported similar strong associations, emphasizing the importance of chromosomal evaluation in patients with covered anal complete [11,12].\u003c/p\u003e\n\u003cp\u003eRegarding functional outcomes, the chronological improvement patterns observed in our study have significant implications for long-term management. The delayed functional improvement in AVF patients, reaching \"excellent\" scores three years later than other subtypes, necessitates extended follow-up and specialized care coordination. This delayed improvement may be attributed to the anatomical complexity of the AVF, particularly the higher confluence points between the rectum and the vagina. The prolonged requirement for bowel management was evidenced by significantly longer glycerin enema treatment periods and persistent constipation challenges that did not reach full scores, even at 11 years of age.\u003c/p\u003e\n\u003cp\u003eBased on our findings, we recommend comprehensive gynecological evaluation for all female patients with low-type ARMs, particularly those with AVF, as part of the preoperative assessment. This should include a systematic evaluation for MRKH syndrome, even in the absence of external genital abnormalities, as the external appearance is typically normal [13]. Early identification enables appropriate family counseling and coordinated surgical planning that addresses both immediate functional needs and long-term reproductive considerations.\u003c/p\u003e\n\u003cp\u003eFor patients with covered anal complete, clinicians should maintain a high index of suspicion for trisomy 21 and modify diagnostic approaches accordingly. Ultrasonographic evaluation may be particularly valuable in these patients, as traditional invertography has been shown to have a sensitivity of only 27% (relative to 86% for ultrasonography) in determining the bowel-skin distance [14]. Recognition of the perineal groove in patients with ANF is important for comprehensive surgical planning and the prevention of long-term complications.\u003c/p\u003e\n\u003cp\u003eConsidering the characteristics of each disease subtype, intensive outpatient defecation management should be maintained until at least 7 years of age for most subtypes, with extended follow-up recommended for AVF patients due to their delayed functional improvement patterns. The association between low-type ARMs and specific congenital anomalies requires specialized expertise and coordinated multidisciplinary care.\u003c/p\u003e\n\u003cp\u003eOur findings have important implications for clinical counseling of families with AVF patients. First, families should be counseled that improvement in defecation function may continue over an extended period, with some patients requiring up to 9 years to achieve optimal outcomes. Second, based on previous reports showing that constipation-related overflow incontinence often improves during adolescence in ARM patients\u0026nbsp;[15], families should be encouraged to maintain consistent bowel management programs throughout childhood. Third, given the prolonged timeline and the potential psychosocial impact of fecal incontinence on social and emotional functioning [16], multidisciplinary support including psychological counseling may benefit these patients and their families. Finally, early initiation of bowel management programs [17] and regular follow-up are essential to optimize long-term functional outcomes in AVF patients.\u003c/p\u003e\n\u003cp\u003eThis study had several limitations. First, as a single-center retrospective study spanning 37 years, treatment strategies and evaluation methods may have varied over time, potentially affecting the outcomes. Second, the small sample sizes in some ARM subtypes, particularly covered anal complete, limits statistical power. Finally, a multivariate analysis was not performed to adjust for potential confounding factors such as associated anomalies and surgical techniques, which may influence defecation function outcomes.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe investigated the detailed characteristics and chronological changes in the postoperative defecation function in female patients with low-type ARMs. Our study demonstrated significant differences between the AVF and non-AVF subtypes in terms of associated anomalies, surgical management, and functional outcomes. The identification of specific associations, including MRKH syndrome with AVF, perineal groove with anocutaneous fistula, and trisomy 21 with covered anal complete, emphasizes the importance of subtype-specific evaluation and management approaches. The delayed functional improvement observed in patients with AVF necessitates extended follow-up and specialized care coordination.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eH.T., N.A., and S.K. wrote the manuscript.\u0026nbsp;T.Y.,\u0026nbsp;O.S., and Y.K. prepared the tables and reviewed the literature. T.Y., N.N., T.Y., K.C., M.M., Y.K., Y.W., and N.A. collected the data based on medical records. K.T.,\u0026nbsp;T.M.,\u0026nbsp;and K.T. provided conceptual advice. I.S. critically reviewed the manuscript and supervised all collected data. All authors\u0026nbsp;have reviewed the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicts of interest in association with the present study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank Brian Quinn for his comments and assistance with this manuscript. This study was supported by a research grant from The Mother and Child Health Foundation, a research grant from the Kawano Masanori Memorial Public Interest Incorporated Foundation for Promotion of Pediatrics, and Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS: 25K22713, 25K11062, 25K11154, 25K11847, 25K11871, 24K06285, 24K15813, 23K20735, 23K07281,\u0026nbsp;23K08031, 23K08052, 23K11934).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cbr\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eShirota C, Suzuki K, Uchida H, Kawashima H, Hinoki A, Tainaka T, Sumida W, Murase N, Oshima K, Chiba K, Makita S, Tanaka Y (2018) Investigation of the feasibility and safety of single-stage anorectoplasty in neonates with anovestibular fistula. Pediatr Surg Int 34(10):1117\u0026ndash;1120\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWakhlu A, Kureel SN, Tandon RK, Wakhlu AK (2009) Long-term results of anterior sagittal anorectoplasty for the treatment of vestibular fistula. J Pediatr Surg 44(10):1913\u0026ndash;1919\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElrouby A, Waheeb S, Koraitim A (2020) Anterior sagittal anorectoplasty as a technique for the repair of female anorectal malformations: A twenty two-years-single-center experience. J Pediatr Surg 55(3):393\u0026ndash;396\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNagano A, Harumatsu T, Sugita K, Iwamoto Y, Ogata M, Takada L, Nishida N, Kedoin C, Murakami M, Yano K, Onishi S, Yamada K, Yamada W, Kawano T, Muto M, Kaji T, Ieiri S (2023) Change over time in the postoperative defecation function in female patients with anovestibular fistula at a single institution: focus on the comparison of anal transposition with anterior sagittal anorectoplasty. Pediatr Surg Int 39(1):266\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKanda Y (2013) Investigation of the freely available easy-to-use software 'EZR' for medical statistics. Bone Marrow Transpl 48(3):452\u0026ndash;458\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLevitt MA, Bischoff A, Breech L, Pena A (2009) Rectovestibular fistula\u0026ndash;rarely recognized associated gynecologic anomalies. J Pediatr Surg 44(6):1261\u0026ndash;1267 discussion 1267\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSamuk I, Amerstorfer EE, Fanjul M, Iacobelli BD, Lisi G, Midrio P, Morandi A, Schmiedeke E, Stenstrom P, Sleeboom C (2020) Perineal Groove: An Anorectal Malformation Network, Consortium Study. J Pediatr 222:207\u0026ndash;212\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCheng H, Wang Z, Zhao Q, Zhu H, Xu T (2018) Perineal Groove: Report of Two Cases and Review of the Literature. Front Pediatr 6:227\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIhn K, Na Y, Ho IG, Oh JT (2020) Clinical characteristics and conservative treatment of perineal groove. J Pediatr Surg 55(8):1507\u0026ndash;1510\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEndo M, Hayashi A, Ishihara M, Maie M, Nagasaki A, Nishi T, Saeki M (1999) Analysis of 1,992 patients with anorectal malformations over the past two decades in Japan. Steering Committee of Japanese Study Group of Anorectal Anomalies. J Pediatr Surg 34(3):435\u0026ndash;441\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBischoff A, Frischer J, Dickie BH, Pe\u0026ntilde;a A (2014) Anorectal malformation without fistula: a defect with unique characteristics. Pediatr Surg Int 30(8):763\u0026ndash;766\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSarkar A, Al Shanafey S, Mourad M, Abudan A (2018) No-fistula vs. fistula type anorectal malformation: Outcome comparative study. J Pediatr Surg 53(9):1734\u0026ndash;1736\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBreech L (2010) Gynecologic concerns in patients with anorectal malformations. Semin Pediatr Surg 19(2):139\u0026ndash;145\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNiedzielski JK (2005) Invertography versus ultrasonography and distal colostography for the determination of bowel-skin distance in children with anorectal malformations. Eur J Pediatr Surg 15(4):262\u0026ndash;267\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRintala RJ, Lindahl HG (2001) Fecal continence in patients having undergone posterior sagittal anorectoplasty procedure for a high anorectal malformation improves at adolescence, as constipation disappears. J Pediatr Surg 36(8):1218\u0026ndash;1221\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrano C, Aminoff D, Lucidi F, Violani C (2012) Long-term disease-specific quality of life in children and adolescent patients with ARM. J Pediatr Surg 47(7):1317\u0026ndash;1322\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePena A, Guardino K, Tovilla JM, Levitt MA, Rodriguez G, Torres R (1998) Bowel management for fecal incontinence in patients with anorectal malformations. J Pediatr Surg 33(1):133\u0026ndash;137\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables are available in the Supplementary Files section.\u003c/p\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":"pediatric-surgery-international","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pesi","sideBox":"Learn more about [Pediatric Surgery International](http://link.springer.com/journal/383)","snPcode":"383","submissionUrl":"https://submission.nature.com/new-submission/383/3","title":"Pediatric Surgery International","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"low-type anorectal malformation, defecation function, female, associated anomaly","lastPublishedDoi":"10.21203/rs.3.rs-8780616/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8780616/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eTo investigate associated anomalies and the postoperative defecation function in female patients with low-type anorectal malformations (ARMs), focusing on comparing anovestibular fistula (AVF) with other subtypes.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003ePatient data were collected between 1984 and 2021. Eighty-seven female patients with low-type ARMs were enrolled after excluding one undetermined case. Associated anomalies, operative procedures, and the long-term defecation function were analyzed and compared between the AVF and non-AVF groups.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAVF was the most common subtype (52.9%), followed by anocutaneous fistula (21.8%), covered anal stenosis (11.5%), anovulvar fistula (10.3%), and covered anal complete (3.4%). Upper urinary tract anomalies and VACTERL association were significantly more frequent in AVF (17.4% and 13.0%) than in non-AVF. Specific associations were identified: trisomy 21 with covered anal complete (100%), perineal groove with anocutaneous fistula (10.5%), and MRKH syndrome with AVF (2.2%). Chronologically, non-AVF low-type ARMs achieved \"excellent\" evacuation scores at 6 years, whereas AVF patients typically achieved this by 9 years. Individual defecation parameters reached full scores by 7 years in all subtypes except AVF, where constipation persisted beyond 11 years.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe postoperative defecation function in female patients with low-type ARMs demonstrates differential improvement patterns, with AVF requiring extended management until at least 9 years.\u003c/p\u003e","manuscriptTitle":"Anovestibular fistula versus other subtypes in female patients with low-type anorectal malformation: Differential patterns in defecation function improvement and associated anomalies at a single institution","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-11 16:37:11","doi":"10.21203/rs.3.rs-8780616/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Accepted","date":"2026-02-06T11:10:50+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-06T11:07:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"340165079514415562491512844803786995236","date":"2026-02-06T11:06:13+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-06T10:29:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-05T19:22:58+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-05T10:36:58+00:00","index":"","fulltext":""},{"type":"submitted","content":"Pediatric Surgery International","date":"2026-02-04T01:14:59+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"pediatric-surgery-international","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pesi","sideBox":"Learn more about [Pediatric Surgery International](http://link.springer.com/journal/383)","snPcode":"383","submissionUrl":"https://submission.nature.com/new-submission/383/3","title":"Pediatric Surgery International","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"69b337b1-eb5a-49e4-b6a0-7405a85544ef","owner":[],"postedDate":"February 11th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-02-23T16:00:16+00:00","versionOfRecord":{"articleIdentity":"rs-8780616","link":"https://doi.org/10.1007/s00383-026-06329-2","journal":{"identity":"pediatric-surgery-international","isVorOnly":false,"title":"Pediatric Surgery International"},"publishedOn":"2026-02-21 15:57:10","publishedOnDateReadable":"February 21st, 2026"},"versionCreatedAt":"2026-02-11 16:37:11","video":"","vorDoi":"10.1007/s00383-026-06329-2","vorDoiUrl":"https://doi.org/10.1007/s00383-026-06329-2","workflowStages":[]},"version":"v1","identity":"rs-8780616","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8780616","identity":"rs-8780616","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}