Clinical Characteristics and Etiological Analysis of Postoperative Bile Leakage after Radical Resection of Choledochal Cyst

Clinical Characteristics and Etiological Analysis of Postoperative Bile Leakage after Radical Resection of Choledochal Cyst | 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 Clinical Characteristics and Etiological Analysis of Postoperative Bile Leakage after Radical Resection of Choledochal Cyst Chengyang Jiang, Yifeng Shao, Kunpeng Yang, Chuanyu Yang, Chengji Dong, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7076168/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Congenital choledochal cyst (CCC) is a common biliary developmental anomaly in children, with Roux-en-Y anastomosis as the standard surgical procedure. However, the prevention and management of postoperative bile leakage remain clinical challenges, and its risk factors are not fully defined. Most existing studies are based on small samples or univariate analyses, lacking systematic evaluation. Objective To clarify the incidence, clinical characteristics, and potential risk factors of bile leakage after radical resection of CCC, to provide evidence-based references for optimizing surgical strategies and reducing postoperative complications. Methods A single-center retrospective cohort study was conducted, including 1853 patients who underwent radical resection of CCC at the Capital Institute of Pediatrics from January 2015 to January 2025. Bile leakage was diagnosed according to the criteria of the International Study Group of Liver Surgery (ISGLS), and cases were screened by 1:1 propensity score matching (PSM). Baseline, preoperative, intraoperative, postoperative, and imaging data were systematically collected, and statistical analyses were performed using R software 4.3.0. Results The incidence of postoperative bile leakage was 2.3% (42 cases), with anastomotic fistula accounting for 73.8%. The preoperative red cell distribution width to platelet count ratio (RPR) in the observation group (bile leakage due to anastomotic fistula) was significantly higher than that in the control group (P < 0.05). The incidence of proximal common bile duct adhesions in the observation group (90.3%) was significantly higher than that in the control group (58.1%, P < 0.05). Bile leakage mostly occurred 1–12 days postoperatively, and secondary surgery confirmed a high incidence of right anastomotic fistula (45.2%). After 2020, the incidence of bile leakage decreased from 2.8–1.1% (P < 0.05), but the proportion of bile leakage related to ectopic hepatic ducts increased. Conclusion Optimizing anastomotic techniques can reduce the incidence of bile leakage, and intraoperative exploration of ectopic hepatic ducts should be strengthened to prevent bile leakage. Postoperative Bile Leakage cyst-cholecystostomy children Figures Figure 1 Introduction Congenital choledochal cyst (CCC) is a congenital malformation characterized by localized dilation of intrahepatic/extrahepatic bile ducts, predominantly occurring in the common bile duct region. It is one of the most common biliary developmental anomalies in children [ 1 ]. The disease has a higher prevalence in Asian populations, with a female-to-male incidence ratio of 4:1 [ 2 – 3 ]. Although choledochal cyst is a benign disorder, untreated cases can lead to complications such as cholangitis, pancreatitis, and even carcinogenesis [ 4 ]. Currently, Roux-en-Y anastomosis has become the standard surgical procedure for treating choledochal cysts [ 5 ]. However, the prevention and management of postoperative complications, particularly bile leakage, remain clinical challenges. Postoperative complications may include hemorrhage, bile leakage, anastomotic stricture, etc. [ 6 ]. Among these, bile leakage, as a common early complication, can trigger refractory ascites, peritonitis, systemic inflammatory response syndrome (SIRS), and even liver failure [ 7 ], significantly prolonging hospitalization, increasing medical burden, and severely threatening the life and health of children. Although domestic and foreign scholars have conducted preliminary explorations on the pathogenesis of bile leakage, its risk factors remain incompletely defined. Existing studies are mostly based on small samples or univariate analyses, lacking systematic evaluations of anastomotic fistula, ectopic hepatic duct management, suspension suture technique, etc. This study aims to clarify the incidence rate, clinical characteristics, and potential risk factors of bile leakage by retrospectively analyzing all cases of radical resection of choledochal cysts admitted to our center from 2015 to 2025, so as to provide evidence-based medical evidence for optimizing surgical strategies and reducing postoperative complications. Materials and Methods Study Design and Participants This was a single-center retrospective cohort study approved by the Ethics Committee of the Capital Institute of Pediatrics (Ethics Approval No.: SHELL20240103), in compliance with the Helsinki Declaration and relevant ethical guidelines. Study data were de-identified, and informed consent was waived due to the retrospective nature of the study. Participants Patients who underwent radical resection of choledochal cysts at our center from January 2015 to January 2025 and developed bile leakage were included. Bile leakage was diagnosed according to the criteria of the International Study Group of Liver Surgery (ISGLS), defined as any of the following: 1. abnormally elevated bilirubin concentration in drainage fluid requiring clinical intervention; 2. surgical drainage or repair due to bile accumulation or bile peritonitis [8]. In our clinical practice, bile leakage was suspected when patients presented with signs of bile peritonitis or bile-like fluid outflow from drainage tubes. Exploratory surgery was indicated when imaging revealed massive free fluid in the abdominal cavity. Patients with bile leakage due to anastomotic issues were selected as the observation group for additional analysis. A 1:1 propensity score matching (PSM) method was used, with surgical age (precise to days) and gender as covariates. Patients without surgical complications who were treated by the same surgeon were selected as the control group, and the caliper value was set at 0.05 to ensure baseline comparability between groups. Data Collection Data were systematically collected via the electronic medical record system, including: (1) Baseline Characteristics Gender, surgical age, presenting symptoms (jaundice, abdominal pain, vomiting, fever, etc.), and prenatal diagnosis results. (2) Preoperative Assessments Routine laboratory indices: Complete blood count (red blood cell count, platelet count, red cell distribution width, etc.), liver function (ALT, AST, TBil, DBil, etc.), inflammatory markers (CRP). Calculated composite indices: Red cell distribution width to platelet count ratio (RPR) = red cell distribution width (RDW) / platelet count (PLT) Platelet to lymphocyte ratio (PLR) = platelet count (PLT) / lymphocyte count (LYM) Neutrophil to lymphocyte ratio (NLR) = neutrophil count (NEU) / lymphocyte count (LYM) (3) Intraoperative Data Cyst size, shape, proximal common bile duct adhesions, variation of right hepatic artery, detection of ectopic hepatic ducts, performance of extended plasty, cyst perforation, and operation duration. (4) Postoperative Data Postoperative day 0 laboratory indices (complete blood count, liver function), liver pathology results (liver fibrosis staging), time of bile leakage occurrence, causes of secondary surgical intervention, and intraoperative findings (location of anastomotic fistula, missed diagnosis of ectopic hepatic ducts, etc.). (5) Imaging Data Preoperative abdominal ultrasound, CT/MRI, and intraoperative cholangiography results. Statistical Methods Analyses were performed using R software 4.3.0. Missing data were handled by listwise deletion, and only complete cases were included. Normality testing for continuous variables: Shapiro-Wilk test for samples ≤50, Kolmogorov-Smirnov test for samples >50, combined with Q-Q plots for distribution assessment. Levene’s test was used to evaluate variance homogeneity for normal distributions. Intergroup comparisons: Independent samples t-test for normally distributed data with homogeneous variance (expressed as "Mean±SD"); Welch’s corrected t-test for unequal variance; Mann-Whitney U test for non-normally distributed independent samples, Wilcoxon signed-rank test for paired samples (expressed as "M (Q1, Q3)"); chi-square test for categorical variables (required ≥80% of cells with expected frequency ≥5 and all cells ≥1), with Fisher’s exact test or low-frequency category merging for non-compliance (expressed as "n (%)"). Two-sided tests were used, with statistical significance set at α=0.05. P-values were retained to 3 decimal places (marked as P<0.001 when P<0.001). 4. Ethical Statement This study complied with the Measures for the Ethical Review of Biomedical Research Involving Humans. All patient data were de-identified to ensure privacy and safety. Results Basic Characteristics of the Study Cohort From January 2015 to January 2025, a total of 1853 radical resections of choledochal cysts were performed at our center, with 42 cases (2.3%) developing postoperative bile leakage. Among these, 31 cases (73.8%) of bile leakage were due to anastomotic issues, constituting the observation group. Using gender and surgical age as covariates, 31 complication-free patients were selected as the control group via 1:1 propensity score matching (PSM) (Figure 1). Demographic and Preoperative Symptom Distribution In the observation group (n=31), there were 12 males (38.7%) and 19 females (61.3%), with an average surgical age of 984.9 days. Presenting symptoms mainly included abdominal pain (51.6%), jaundice (38.7%), and cholangitis (35.5%), with prenatal diagnosis identified in 13 cases (41.9%). The control group showed no significant differences in gender, surgical age, or symptom distribution, with no statistically significant intergroup differences (Table 1). Analysis of Preoperative Laboratory Indices Routine blood counts (white blood cells, red blood cells, platelet count) and biochemical indices (liver function, inflammatory factors) showed no significant intergroup differences. Composite index analysis revealed that the red cell distribution width to platelet count ratio (RPR) in the observation group was significantly higher than that in the control group (P < 0.05), while no significant differences were observed in platelet to lymphocyte ratio (PLR), neutrophil to lymphocyte ratio (NLR), aspartate aminotransferase to platelet count ratio (APRI), or aspartate aminotransferase to alanine aminotransferase ratio (AAR) (Table 2). Intraoperative Findings Comparison Intraoperatively, 28 cases (90.3%) in the observation group showed proximal common bile duct adhesions, significantly higher than 18 cases (58.1%) in the control group (P < 0.05). No significant differences were found between groups in cyst shape, right hepatic artery variation, initial detection rate of ectopic hepatic ducts, extended plasty, cyst perforation rate, or operation duration (Table 3). Postoperative day 0 laboratory tests (blood count, liver and kidney function) also showed no significant differences (Table 4). Liver Pathology-related Characteristics The postoperative liver fibrosis diagnosis rate was 25.8% (8/31) in the observation group, higher than 16.1% (5/31) and 6.5% (2/31) in the control group, though the difference did not reach statistical significance. Analysis of Clinical Characteristics of Bile Leakage Bile leakage was detected 1 to 12 days postoperatively, with an average secondary surgery time of postoperative day 4. Typical symptoms before secondary surgery included changes in drainage volume and properties in 31 cases (73.8%), peritoneal irritation signs in 30 (71.4%), fever in 19 (45.3%), abdominal distension in 18 (42.9%), and abdominal pain in 16 (38.1%). Secondary surgery confirmed: 31 cases (73.8%) of anastomotic fistula, with 45.2% (14/31) located on the right wall of the anastomosis, managed by deconstruction and re-anastomosis in 15 cases (48.4%) and fistula repair in others; 7 cases (16.7%) of missed ectopic hepatic ducts, all located on the right and posterior sides of the original anastomosis; 3 cases (7.1%) of leakage at suspension suture sites, on the anterior and left walls of the common hepatic duct; and 1 case (2.4%) of blind end fistula in the biliary limb. Open surgery conversion occurred in 5 cases (11.9%) during secondary surgery (Table 5). Eight patients developed recurrent bile leakage after secondary surgery, requiring tertiary surgery, which confirmed: 5 cases (62.5%) of recurrent anastomotic fistula, with 2 (40%) on the right wall, all managed by redo hepaticojejunostomy; and 3 cases (37.5%) of newly detected ectopic hepatic ducts (Table 5). Analysis of Bile Leakage Causes in Different Periods Bile leakage patients who underwent secondary surgery were grouped by operation time using 2020 as the boundary. From January 2015 to December 2019, 987 radical resections were performed with a bile leakage rate of 2.8% (28/987); from January 2020 to January 2025, 1238 surgeries showed a significantly reduced leakage rate of 1.1% (14/1238) (P<0.05). The composition of bile leakage causes differed significantly between periods. From 2015 to 2020, anastomotic fistula was the main cause, accounting for 82.1% (23/28), while missed ectopic hepatic ducts and suspension suture leakage accounted for 10.7% (3/28) and 7.1% (2/28), respectively. From 2020 to 2025, anastomotic leakage decreased to 57.1% (8/14), while missed ectopic hepatic ducts increased to 28.6% (4/14), with the first case of blind end fistula (1/14, 7.1%). The incidence of suspension suture leakage remained stable between periods (7.1% vs. 7.1%, P>0.05) (Table 6). Discussion Bile leakage after radical resection of choledochal cysts is a critical complication affecting patient outcomes, with its incidence and underlying mechanisms consistently being focal points in clinical practice. This study retrospectively analyzed all cases of radical choledochal cyst resection at our center from 2015 to 2024, systematically exploring the clinical characteristics and related factors of postoperative bile leakage, thus providing comprehensive clinical data for this field. The incidence of postoperative bile leakage at our center was 2.3%, consistent with previous single-center studies [9]. In terms of etiological composition, anastomotic fistula dominated (82.1%), followed by untreated ectopic hepatic ducts (16.7%), suspension suture leakage (7.1%), and blind end fistula of the biliary limb (2.4%). This study first identified that the preoperative red cell distribution width to platelet count ratio (RPR) was significantly higher in the bile leakage group than in the control group. As a comprehensive index reflecting systemic inflammatory and nutritional status, the elevation of RPR may be associated with a dual mechanism: 1. Inflammatory response: Chronic inflammation can induce erythropoietic heterogeneity (manifested as increased RDW) [10], while shortening platelet lifespan or inhibiting bone marrow production leads to decreased platelet count [11], collectively resulting in elevated RPR; 2.Hepatic dysfunction: Choledochal cysts may be accompanied by hepatic parenchymal injury, triggering malnutrition and oxidative stress imbalance [12], which inhibits the maturation and differentiation of red blood cells and platelets, leading to irregular red blood cells and decreased platelet count in peripheral blood [13-15]. Although this study did not observe differences in liver fibrosis degree between the bile leakage and control groups, the extensive application of RPR in liver diseases [16-17] suggests it may serve as a potential predictor of bile leakage. It is emphasized that this study is retrospective, and the predictive efficacy of RPR requires validation in large-sample prospective studies. Postoperative symptoms such as fever, abdominal pain, distension, peritoneal irritation signs, and abnormal abdominal drainage, though common in bile leakage, lack specificity and require comprehensive judgment combined with imaging and clinical experience. When these signs appear, bile leakage should be highly suspected, and timely intervention is necessary. The positional distribution of anastomotic fistulas showed a high incidence in the right anastomosis, which may be related to the following reasons: 1) The gallbladder is located on the right side of the common bile duct, and thermal injury from electrocautery during gallbladder dissection can impair anastomotic healing; 2) During hepaticojejunostomy, the right side is typically anastomosed last, possibly resulting in sparser stitches and insufficient tightness; 3) Surgeons often tie knots on the right anastomosis, which may concentrate tension and hinder healing. Analysis of cases in different periods revealed that before 2020, the postoperative bile leakage rate at our center was 2.8%, with the main causes being anastomotic fistula (82.1%) and ectopic hepatic ducts (10.7%); after 2020, the leakage rate decreased to 1.1%, with anastomotic fistula (57.1%) and ectopic hepatic ducts (28.6%) as the primary causes. With improved surgical techniques, the postoperative bile leakage rate at our center showed a significant downward trend, particularly a notable reduction in cases due to anastomotic issues. This highlights that enhancing anastomotic skills is the most critical strategy to avoid bile leakage. With improved anastomotic techniques, the exploration of ectopic hepatic ducts has become an important issue in radical choledochal cyst resection. During cyst dissection, electrocoagulation may temporarily seal small ectopic hepatic ducts, but increased bile secretion postoperatively can disrupt the seal, causing delayed bile leakage [18]. In patients with existing bile leakage, tissue edema during secondary surgery may obscure ectopic hepatic ducts, leading to missed detection and necessitating tertiary open surgery, which significantly increases patient trauma. Notably, some patients may have concurrent anastomotic fistula and ectopic hepatic ducts; after addressing the fistula, neglecting ectopic duct exploration can cause recurrent bile leakage. Additionally, with the application of suspension suture techniques, leakage related to suspension sutures has emerged. During anastomosis, it is crucial to ensure the hepatic duct stump is fully incorporated into the anastomosis or that suspension suture leaks are precisely repaired to avoid bile leakage from improper suture management. Research Limitations and Future Directions This study, as a single-center retrospective analysis, has limitations including a limited sample size, and the causal relationship between RPR and bile leakage remains undefined. Future multi-center prospective studies are warranted to further validate the predictive value of RPR and explore its dynamic association with postoperative bile leakage. Declarations Disclosure statement All authors declare no conflict of interest. Funding The project is supported by the Research Unit of Minimally Invasive Pediatric Surgery on Diagnosis and Treatment, Chinese Academy of Medical Sciences 2021RU015, Beijing Hospital Authority’s Ascent Plan, Code: DFL20221101. Author Contribution CJ and YS: data acquisition and drafting of manuscript; CD, KY and CY: review & editing ; AM and MD.: critical revision of manuscript. Data Availability To protect patient privacy and confidentiality, the data supporting the findings of this study are not publicly available. However, de-identified data used in this study may be available from the corresponding author upon reasonable request, strictly for scientific research purposes. Data sharing is subject to institutional data protection policies and requires a formal agreement. References Brown ZJ ， Baghdadi A ， Kamel I ，et al. Diagnosis and management of choledochal cysts[J]．HPB(Oxford)， 2023，25(1)：14-25. 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Aslam H, Oza F, Ahmed K, Kopel J, Aloysius MM, Ali A, Dahiya DS, Aziz M, Perisetti A, Goyal H. The Role of Red Cell Distribution Width as a Prognostic Marker in Chronic Liver Disease: A Literature Review. Int J Mol Sci. 2023;24 doi: 10.3390/ijms24043487. Anand I., Mcmurray J.J., Whitmore J., et al. Anemia and its relationship to clinical outcome in heart failure. Circulation. 2004;110(2):149–154. doi: 10.1161/01.CIR.0000134279.79571.73. Groenveld H.F., Januzzi J.L., Damman K., et al. Anemia and mortality in heart failure patients a systematic review and meta-analysis. J. Am. Coll. Cardiol. 2008;52(10):818–827. doi: 10.1016/j.jacc.2008.04.061. Brissot E., Troadec M.B., LoréAL O., et al. Iron and platelets: a subtle, under-recognized relationship. Am. J. Hematol. 2021;96(8):1008–1016. doi: 10.1002/ajh.26189. Milić S, Mikolasević I, Radić M, Hauser G, Stimac D. Clinical utility of red cell distribution width in alcoholic and non-alcoholic liver cirrhosis. Coll Antropol. 2011;35 Suppl 2:335–338. Taefi A, Huang CC, Kolli K, Ebrahimi S, Patel M. Red cell distribution width to platelet ratio, a useful indicator of liver fibrosis in chronic hepatitis patients. Hepatol Int. 2015;9:454–460. doi: 10.1007/s12072-015-9638-9. Diao M ， Li L ， Cheng W ．Laparoscopic management for aberrant hepatic duct in children with choledochal cysts[J]．Surg Endosc， 2019，33(7)：2376—2380. Tables Tables 1 to 6 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Table1.xlsx Table2.xlsx Table3.xlsx Table4.xlsx Table5.xlsx Table6.xlsx Cite Share Download PDF Status: Posted Version 1 posted 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-7076168","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":489403956,"identity":"0ddae3ab-b4ae-4317-b513-555dea2b0359","order_by":0,"name":"Chengyang Jiang","email":"","orcid":"","institution":"Capital Institute of Pediatrics,Chinese Academy of Medical Sciences \u0026 Peking Union Medical College","correspondingAuthor":false,"prefix":"","firstName":"Chengyang","middleName":"","lastName":"Jiang","suffix":""},{"id":489403963,"identity":"3318f121-f140-4b7d-a1a1-1238cd63cbde","order_by":1,"name":"Yifeng 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11:34:18","extension":"xlsx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":9893,"visible":true,"origin":"","legend":"","description":"","filename":"Table5.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7076168/v1/a1e8070445a1b0e66b46af2b.xlsx"},{"id":87576465,"identity":"9ac4a175-91c6-4afc-ab4d-093e1e184e75","added_by":"auto","created_at":"2025-07-25 11:42:19","extension":"xlsx","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":9328,"visible":true,"origin":"","legend":"","description":"","filename":"Table6.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7076168/v1/3f9bd45608f03c834bc4ed01.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Clinical Characteristics and Etiological Analysis of Postoperative Bile Leakage after Radical Resection of Choledochal Cyst","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCongenital choledochal cyst (CCC) is a congenital malformation characterized by localized dilation of intrahepatic/extrahepatic bile ducts, predominantly occurring in the common bile duct region. It is one of the most common biliary developmental anomalies in children [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The disease has a higher prevalence in Asian populations, with a female-to-male incidence ratio of 4:1 [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Although choledochal cyst is a benign disorder, untreated cases can lead to complications such as cholangitis, pancreatitis, and even carcinogenesis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eCurrently, Roux-en-Y anastomosis has become the standard surgical procedure for treating choledochal cysts [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, the prevention and management of postoperative complications, particularly bile leakage, remain clinical challenges. Postoperative complications may include hemorrhage, bile leakage, anastomotic stricture, etc. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Among these, bile leakage, as a common early complication, can trigger refractory ascites, peritonitis, systemic inflammatory response syndrome (SIRS), and even liver failure [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], significantly prolonging hospitalization, increasing medical burden, and severely threatening the life and health of children.\u003c/p\u003e\u003cp\u003eAlthough domestic and foreign scholars have conducted preliminary explorations on the pathogenesis of bile leakage, its risk factors remain incompletely defined. Existing studies are mostly based on small samples or univariate analyses, lacking systematic evaluations of anastomotic fistula, ectopic hepatic duct management, suspension suture technique, etc. This study aims to clarify the incidence rate, clinical characteristics, and potential risk factors of bile leakage by retrospectively analyzing all cases of radical resection of choledochal cysts admitted to our center from 2015 to 2025, so as to provide evidence-based medical evidence for optimizing surgical strategies and reducing postoperative complications.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy Design and Participants\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis was a single-center retrospective cohort study approved by the Ethics Committee of the Capital Institute of Pediatrics (Ethics Approval No.: SHELL20240103), in compliance with the Helsinki Declaration and relevant ethical guidelines. Study data were de-identified, and informed consent was waived due to the retrospective nature of the study.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eParticipants\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients who underwent radical resection of choledochal cysts at our center from January 2015 to January 2025 and developed bile leakage were included. Bile leakage was diagnosed according to the criteria of the International Study Group of Liver Surgery (ISGLS), defined as any of the following: 1. abnormally elevated bilirubin concentration in drainage fluid requiring clinical intervention; 2. surgical drainage or repair due to bile accumulation or bile peritonitis [8]. In our clinical practice, bile leakage was suspected when patients presented with signs of bile peritonitis or bile-like fluid outflow from drainage tubes. Exploratory surgery was indicated when imaging revealed massive free fluid in the abdominal cavity.\u003c/p\u003e\n\n\u003cp\u003ePatients with bile leakage due to anastomotic issues were selected as the observation group for additional analysis. A 1:1 propensity score matching (PSM) method was used, with surgical age (precise to days) and gender as covariates. Patients without surgical complications who were treated by the same surgeon were selected as the control group, and the caliper value was set at 0.05 to ensure baseline comparability between groups.\u003c/p\u003e\n\n\n\u003cp\u003e\u003cstrong\u003eData Collection\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData were systematically collected via the electronic medical record system, including:\u003c/p\u003e\n\u003cp\u003e(1) Baseline Characteristics\u003c/p\u003e\n\u003cp\u003eGender, surgical age, presenting symptoms (jaundice, abdominal pain, vomiting, fever, etc.), and prenatal diagnosis results.\u003c/p\u003e\n\u003cp\u003e(2) Preoperative Assessments\u003c/p\u003e\n\u003cp\u003eRoutine laboratory indices: Complete blood count (red blood cell count, platelet count, red cell distribution width, etc.), liver function (ALT, AST, TBil, DBil, etc.), inflammatory markers (CRP).\u003c/p\u003e\n\u003cp\u003eCalculated composite indices:\u003c/p\u003e\n\u003cp\u003eRed cell distribution width to platelet count ratio (RPR) = red cell distribution width (RDW) / platelet count (PLT)\u003c/p\u003e\n\u003cp\u003ePlatelet to lymphocyte ratio (PLR) = platelet count (PLT) / lymphocyte count (LYM)\u003c/p\u003e\n\u003cp\u003eNeutrophil to lymphocyte ratio (NLR) = neutrophil count (NEU) / lymphocyte count (LYM)\u003c/p\u003e\n\u003cp\u003e(3) Intraoperative Data\u003c/p\u003e\n\u003cp\u003eCyst size, shape, proximal common bile duct adhesions, variation of right hepatic artery, detection of ectopic hepatic ducts, performance of extended plasty, cyst perforation, and operation duration.\u003c/p\u003e\n\u003cp\u003e(4) Postoperative Data\u003c/p\u003e\n\u003cp\u003ePostoperative day 0 laboratory indices (complete blood count, liver function), liver pathology results (liver fibrosis staging), time of bile leakage occurrence, causes of secondary surgical intervention, and intraoperative findings (location of anastomotic fistula, missed diagnosis of ectopic hepatic ducts, etc.).\u003c/p\u003e\n\u003cp\u003e(5) Imaging Data\u003c/p\u003e\n\u003cp\u003ePreoperative abdominal ultrasound, CT/MRI, and intraoperative cholangiography results.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eStatistical Methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnalyses were performed using R software 4.3.0. Missing data were handled by listwise deletion, and only complete cases were included.\u003c/p\u003e\n\n\u003cp\u003eNormality testing for continuous variables: Shapiro-Wilk test for samples \u0026le;50, Kolmogorov-Smirnov test for samples \u0026gt;50, combined with Q-Q plots for distribution assessment. Levene\u0026rsquo;s test was used to evaluate variance homogeneity for normal distributions.\u003c/p\u003e\n\u003cp\u003eIntergroup comparisons: Independent samples t-test for normally distributed data with homogeneous variance (expressed as \u0026quot;Mean\u0026plusmn;SD\u0026quot;); Welch\u0026rsquo;s corrected t-test for unequal variance; Mann-Whitney U test for non-normally distributed independent samples, Wilcoxon signed-rank test for paired samples (expressed as \u0026quot;M (Q1, Q3)\u0026quot;); chi-square test for categorical variables (required \u0026ge;80% of cells with expected frequency \u0026ge;5 and all cells \u0026ge;1), with Fisher\u0026rsquo;s exact test or low-frequency category merging for non-compliance (expressed as \u0026quot;n (%)\u0026quot;).\u003c/p\u003e\n\u003cp\u003eTwo-sided tests were used, with statistical significance set at \u0026alpha;=0.05. P-values were retained to 3 decimal places (marked as P\u0026lt;0.001 when P\u0026lt;0.001).\u003c/p\u003e\n\u003cp\u003e4. Ethical Statement\u003c/p\u003e\n\u003cp\u003eThis study complied with the Measures for the Ethical Review of Biomedical Research Involving Humans. All patient data were de-identified to ensure privacy and safety.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eBasic Characteristics of the Study Cohort\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFrom January 2015 to January 2025, a total of 1853 radical resections of choledochal cysts were performed at our center, with 42 cases (2.3%) developing postoperative bile leakage. Among these, 31 cases (73.8%) of bile leakage were due to anastomotic issues, constituting the observation group. Using gender and surgical age as covariates, 31 complication-free patients were selected as the control group via 1:1 propensity score matching (PSM) (Figure 1).\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDemographic and Preoperative Symptom Distribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the observation group (n=31), there were 12 males (38.7%) and 19 females (61.3%), with an average surgical age of 984.9 days. Presenting symptoms mainly included abdominal pain (51.6%), jaundice (38.7%), and cholangitis (35.5%), with prenatal diagnosis identified in 13 cases (41.9%). The control group showed no significant differences in gender, surgical age, or symptom distribution, with no statistically significant intergroup differences (Table 1).\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAnalysis of Preoperative Laboratory Indices\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRoutine blood counts (white blood cells, red blood cells, platelet count) and biochemical indices (liver function, inflammatory factors) showed no significant intergroup differences. Composite index analysis revealed that the red cell distribution width to platelet count ratio (RPR) in the observation group was significantly higher than that in the control group (P \u0026lt; 0.05), while no significant differences were observed in platelet to lymphocyte ratio (PLR), neutrophil to lymphocyte ratio (NLR), aspartate aminotransferase to platelet count ratio (APRI), or aspartate aminotransferase to alanine aminotransferase ratio (AAR) (Table 2).\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eIntraoperative Findings Comparison\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIntraoperatively, 28 cases (90.3%) in the observation group showed proximal common bile duct adhesions, significantly higher than 18 cases (58.1%) in the control group (P \u0026lt; 0.05). No significant differences were found between groups in cyst shape, right hepatic artery variation, initial detection rate of ectopic hepatic ducts, extended plasty, cyst perforation rate, or operation duration (Table 3). Postoperative day 0 laboratory tests (blood count, liver and kidney function) also showed no significant differences (Table 4).\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eLiver Pathology-related Characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe postoperative liver fibrosis diagnosis rate was 25.8% (8/31) in the observation group, higher than 16.1% (5/31) and 6.5% (2/31) in the control group, though the difference did not reach statistical significance.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAnalysis of Clinical Characteristics of Bile Leakage\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBile leakage was detected 1 to 12 days postoperatively, with an average secondary surgery time of postoperative day 4. Typical symptoms before secondary surgery included changes in drainage volume and properties in 31 cases (73.8%), peritoneal irritation signs in 30 (71.4%), fever in 19 (45.3%), abdominal distension in 18 (42.9%), and abdominal pain in 16 (38.1%). Secondary surgery confirmed: 31 cases (73.8%) of anastomotic fistula, with 45.2% (14/31) located on the right wall of the anastomosis, managed by deconstruction and re-anastomosis in 15 cases (48.4%) and fistula repair in others; 7 cases (16.7%) of missed ectopic hepatic ducts, all located on the right and posterior sides of the original anastomosis; 3 cases (7.1%) of leakage at suspension suture sites, on the anterior and left walls of the common hepatic duct; and 1 case (2.4%) of blind end fistula in the biliary limb. Open surgery conversion occurred in 5 cases (11.9%) during secondary surgery (Table 5).\u003c/p\u003e\n\n\u003cp\u003eEight patients developed recurrent bile leakage after secondary surgery, requiring tertiary surgery, which confirmed: 5 cases (62.5%) of recurrent anastomotic fistula, with 2 (40%) on the right wall, all managed by redo hepaticojejunostomy; and 3 cases (37.5%) of newly detected ectopic hepatic ducts (Table 5).\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAnalysis of Bile Leakage Causes in Different Periods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBile leakage patients who underwent secondary surgery were grouped by operation time using 2020 as the boundary. From January 2015 to December 2019, 987 radical resections were performed with a bile leakage rate of 2.8% (28/987); from January 2020 to January 2025, 1238 surgeries showed a significantly reduced leakage rate of 1.1% (14/1238) (P\u0026lt;0.05).\u003c/p\u003e\n\n\u003cp\u003eThe composition of bile leakage causes differed significantly between periods. From 2015 to 2020, anastomotic fistula was the main cause, accounting for 82.1% (23/28), while missed ectopic hepatic ducts and suspension suture leakage accounted for 10.7% (3/28) and 7.1% (2/28), respectively. From 2020 to 2025, anastomotic leakage decreased to 57.1% (8/14), while missed ectopic hepatic ducts increased to 28.6% (4/14), with the first case of blind end fistula (1/14, 7.1%). The incidence of suspension suture leakage remained stable between periods (7.1% vs. 7.1%, P\u0026gt;0.05) (Table 6).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eBile leakage after radical resection of choledochal cysts is a critical complication affecting patient outcomes, with its incidence and underlying mechanisms consistently being focal points in clinical practice. This study retrospectively analyzed all cases of radical choledochal cyst resection at our center from 2015 to 2024, systematically exploring the clinical characteristics and related factors of postoperative bile leakage, thus providing comprehensive clinical data for this field.\u003c/p\u003e\n\n\u003cp\u003eThe incidence of postoperative bile leakage at our center was 2.3%, consistent with previous single-center studies [9]. In terms of etiological composition, anastomotic fistula dominated (82.1%), followed by untreated ectopic hepatic ducts (16.7%), suspension suture leakage (7.1%), and blind end fistula of the biliary limb (2.4%).\u003c/p\u003e\n\n\u003cp\u003eThis study first identified that the preoperative red cell distribution width to platelet count ratio (RPR) was significantly higher in the bile leakage group than in the control group. As a comprehensive index reflecting systemic inflammatory and nutritional status, the elevation of RPR may be associated with a dual mechanism: 1. Inflammatory response: Chronic inflammation can induce erythropoietic heterogeneity (manifested as increased RDW) [10], while shortening platelet lifespan or inhibiting bone marrow production leads to decreased platelet count [11], collectively resulting in elevated RPR; 2.Hepatic dysfunction: Choledochal cysts may be accompanied by hepatic parenchymal injury, triggering malnutrition and oxidative stress imbalance [12], which inhibits the maturation and differentiation of red blood cells and platelets, leading to irregular red blood cells and decreased platelet count in peripheral blood [13-15]. Although this study did not observe differences in liver fibrosis degree between the bile leakage and control groups, the extensive application of RPR in liver diseases [16-17] suggests it may serve as a potential predictor of bile leakage. It is emphasized that this study is retrospective, and the predictive efficacy of RPR requires validation in large-sample prospective studies.\u003c/p\u003e\n\n\u003cp\u003ePostoperative symptoms such as fever, abdominal pain, distension, peritoneal irritation signs, and abnormal abdominal drainage, though common in bile leakage, lack specificity and require comprehensive judgment combined with imaging and clinical experience. When these signs appear, bile leakage should be highly suspected, and timely intervention is necessary.\u003c/p\u003e\n\n\u003cp\u003eThe positional distribution of anastomotic fistulas showed a high incidence in the right anastomosis, which may be related to the following reasons: 1) The gallbladder is located on the right side of the common bile duct, and thermal injury from electrocautery during gallbladder dissection can impair anastomotic healing; 2) During hepaticojejunostomy, the right side is typically anastomosed last, possibly resulting in sparser stitches and insufficient tightness; 3) Surgeons often tie knots on the right anastomosis, which may concentrate tension and hinder healing.\u003c/p\u003e\n\n\u003cp\u003eAnalysis of cases in different periods revealed that before 2020, the postoperative bile leakage rate at our center was 2.8%, with the main causes being anastomotic fistula (82.1%) and ectopic hepatic ducts (10.7%); after 2020, the leakage rate decreased to 1.1%, with anastomotic fistula (57.1%) and ectopic hepatic ducts (28.6%) as the primary causes. With improved surgical techniques, the postoperative bile leakage rate at our center showed a significant downward trend, particularly a notable reduction in cases due to anastomotic issues. This highlights that enhancing anastomotic skills is the most critical strategy to avoid bile leakage.\u003c/p\u003e\n\n\u003cp\u003eWith improved anastomotic techniques, the exploration of ectopic hepatic ducts has become an important issue in radical choledochal cyst resection. During cyst dissection, electrocoagulation may temporarily seal small ectopic hepatic ducts, but increased bile secretion postoperatively can disrupt the seal, causing delayed bile leakage [18]. In patients with existing bile leakage, tissue edema during secondary surgery may obscure ectopic hepatic ducts, leading to missed detection and necessitating tertiary open surgery, which significantly increases patient trauma. Notably, some patients may have concurrent anastomotic fistula and ectopic hepatic ducts; after addressing the fistula, neglecting ectopic duct exploration can cause recurrent bile leakage. Additionally, with the application of suspension suture techniques, leakage related to suspension sutures has emerged. During anastomosis, it is crucial to ensure the hepatic duct stump is fully incorporated into the anastomosis or that suspension suture leaks are precisely repaired to avoid bile leakage from improper suture management.\u003c/p\u003e\n\n\n\u003cp\u003e\u003cstrong\u003eResearch Limitations and Future Directions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003eThis study, as a single-center retrospective analysis, has limitations including a limited sample size, and the causal relationship between RPR and bile leakage remains undefined. Future multi-center prospective studies are warranted to further validate the predictive value of RPR and explore its dynamic association with postoperative bile leakage.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eDisclosure statement\u003c/h2\u003e\n\u003cp\u003eAll authors declare no conflict of interest.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThe project is supported by the Research Unit of Minimally Invasive Pediatric Surgery on Diagnosis and Treatment, Chinese Academy of Medical Sciences 2021RU015, Beijing Hospital Authority\u0026rsquo;s Ascent Plan, Code: DFL20221101.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eCJ and YS: data acquisition and drafting of manuscript; CD, KY and CY: review \u0026amp; editing ; AM and MD.: critical revision of manuscript.\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eTo protect patient privacy and confidentiality, the data supporting the findings of this study are not publicly available. However, de-identified data used in this study may be available from the corresponding author upon reasonable request, strictly for scientific research purposes. Data sharing is subject to institutional data protection policies and requires a formal agreement.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBrown ZJ ， Baghdadi A ， Kamel I ，et al. Diagnosis and management of choledochal cysts[J]．HPB(Oxford)， 2023，25(1)：14-25.\u003c/li\u003e\n\u003cli\u003eDumitrascu T, Lupescu I, Ionescu M. The Todani classification for bile duct cysts: an overview. Acta Chir Belg. 2012;112:340\u0026ndash;345. doi: 10.1080/00015458.2012.11680849. \u003c/li\u003e\n\u003cli\u003eSoares KC, Arnaoutakis DJ, Kamel I, Rastegar N, Anders R, Maithel S, et al. Choledochal cysts: presentation, clinical differentiation, and management. J Am Coll Surg. 2014;219:1167\u0026ndash;1180. doi: 10.1016/j.jamcollsurg.2014.04.023.\u003c/li\u003e\n\u003cli\u003eHuang CS, Huang CC, Chen DF. Choledochal cysts: differences between pediatric and adult patients. J Gastrointest Surg. 2010;14:1105\u0026ndash;1110. doi: 10.1007/s11605-010-1209-8.\u003c/li\u003e\n\u003cli\u003eFarello GA, Cerofolini A, Rebonato M, Bergamaschi G, Ferrari C, Chiappetta A. Congenital choledochal cyst: video-guided laparoscopic treatment. Surg Laparosc Endosc. 1995;5:354\u0026ndash;358.\u003c/li\u003e\n\u003cli\u003eDiao M ， Li L ， Cheng W ．Laparoscopic versus Open Roux-en-Y hepatojejunostomy for children with choledochal cysts：intermediate-term follow-up results[J]．Surg Endosc， 2011，25(5)：1567\u0026mdash;1573. DOI： 10.1007/s00464\u0026mdash;010\u0026mdash;1435\u0026mdash;x .\u003c/li\u003e\n\u003cli\u003eNakano, R., Ohira, M., Kobayashi, T., et al. (2018) Independent Risk Factors that Predict Bile Leakage after Hepatectomy for Hepatocellular Carcinoma: Cohort Study. International Journal of Surgery, 57, 1-7.\u003c/li\u003e\n\u003cli\u003ePanaro, F., Hacina, L., Bouyabrine, H., et al. (2016) Risk Factors for Postoperative Bile Leakage: A Retrospective Single-Center Analysis of 411 Hepatectomies. Hepatobiliary \u0026amp; Pancreatic Diseases International, 15, 81-86.\u003c/li\u003e\n\u003cli\u003eTang, S.T., Yang, Y., Wang, Y., et al. (2011) Laparoscopic Choledochal Cyst Excision, Hepaticojejunostomy, and Extracorporeal Roux-en-Y Anastomosis: A Technical Skill and Intermediate-Term Report in 62 Cases. Surgical Endoscopy, 25, 416-422.\u003c/li\u003e\n\u003cli\u003eWeiss G., Goodnough L.T. Anemia of chronic disease. N. Engl. J. Med. 2005;352(10):1011\u0026ndash;1023. doi: 10.1056/NEJMra041809.\u003c/li\u003e\n\u003cli\u003ePLTGremmel T., Frelinger A.L., 3Rd, Michelson A.D. Platelet physiology. Semin. Thromb. Hemost. 2016;42(3):191\u0026ndash;204. doi: 10.1055/s-0035-1564835. \u003c/li\u003e\n\u003cli\u003eAslam H, Oza F, Ahmed K, Kopel J, Aloysius MM, Ali A, Dahiya DS, Aziz M, Perisetti A, Goyal H. The Role of Red Cell Distribution Width as a Prognostic Marker in Chronic Liver Disease: A Literature Review. Int J Mol Sci. 2023;24 doi: 10.3390/ijms24043487. \u003c/li\u003e\n\u003cli\u003eAnand I., Mcmurray J.J., Whitmore J., et al. Anemia and its relationship to clinical outcome in heart failure. Circulation. 2004;110(2):149\u0026ndash;154. doi: 10.1161/01.CIR.0000134279.79571.73.\u003c/li\u003e\n\u003cli\u003eGroenveld H.F., Januzzi J.L., Damman K., et al. Anemia and mortality in heart failure patients a systematic review and meta-analysis. J. Am. Coll. Cardiol. 2008;52(10):818\u0026ndash;827. doi: 10.1016/j.jacc.2008.04.061. \u003c/li\u003e\n\u003cli\u003eBrissot E., Troadec M.B., Lor\u0026eacute;AL O., et al. Iron and platelets: a subtle, under-recognized relationship. Am. J. Hematol. 2021;96(8):1008\u0026ndash;1016. doi: 10.1002/ajh.26189.\u003c/li\u003e\n\u003cli\u003eMilić S, Mikolasević I, Radić M, Hauser G, Stimac D. Clinical utility of red cell distribution width in alcoholic and non-alcoholic liver cirrhosis. Coll Antropol. 2011;35 Suppl 2:335\u0026ndash;338.\u003c/li\u003e\n\u003cli\u003eTaefi A, Huang CC, Kolli K, Ebrahimi S, Patel M. Red cell distribution width to platelet ratio, a useful indicator of liver fibrosis in chronic hepatitis patients. Hepatol Int. 2015;9:454\u0026ndash;460. doi: 10.1007/s12072-015-9638-9.\u003c/li\u003e\n\u003cli\u003eDiao M ， Li L ， Cheng W ．Laparoscopic management for aberrant hepatic duct in children with choledochal cysts[J]．Surg Endosc， 2019，33(7)：2376\u0026mdash;2380.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 6 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Postoperative Bile Leakage, cyst-cholecystostomy, children","lastPublishedDoi":"10.21203/rs.3.rs-7076168/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7076168/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eCongenital choledochal cyst (CCC) is a common biliary developmental anomaly in children, with Roux-en-Y anastomosis as the standard surgical procedure. However, the prevention and management of postoperative bile leakage remain clinical challenges, and its risk factors are not fully defined. Most existing studies are based on small samples or univariate analyses, lacking systematic evaluation.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e\u003cp\u003eTo clarify the incidence, clinical characteristics, and potential risk factors of bile leakage after radical resection of CCC, to provide evidence-based references for optimizing surgical strategies and reducing postoperative complications.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eA single-center retrospective cohort study was conducted, including 1853 patients who underwent radical resection of CCC at the Capital Institute of Pediatrics from January 2015 to January 2025. Bile leakage was diagnosed according to the criteria of the International Study Group of Liver Surgery (ISGLS), and cases were screened by 1:1 propensity score matching (PSM). Baseline, preoperative, intraoperative, postoperative, and imaging data were systematically collected, and statistical analyses were performed using R software 4.3.0.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe incidence of postoperative bile leakage was 2.3% (42 cases), with anastomotic fistula accounting for 73.8%. The preoperative red cell distribution width to platelet count ratio (RPR) in the observation group (bile leakage due to anastomotic fistula) was significantly higher than that in the control group (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The incidence of proximal common bile duct adhesions in the observation group (90.3%) was significantly higher than that in the control group (58.1%, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Bile leakage mostly occurred 1\u0026ndash;12 days postoperatively, and secondary surgery confirmed a high incidence of right anastomotic fistula (45.2%). After 2020, the incidence of bile leakage decreased from 2.8\u0026ndash;1.1% (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05), but the proportion of bile leakage related to ectopic hepatic ducts increased.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eOptimizing anastomotic techniques can reduce the incidence of bile leakage, and intraoperative exploration of ectopic hepatic ducts should be strengthened to prevent bile leakage.\u003c/p\u003e","manuscriptTitle":"Clinical Characteristics and Etiological Analysis of Postoperative Bile Leakage after Radical Resection of Choledochal Cyst","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-25 11:34:13","doi":"10.21203/rs.3.rs-7076168/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a02fee31-5a07-4852-b28f-c21f5537d6ba","owner":[],"postedDate":"July 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-17T22:08:12+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-25 11:34:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7076168","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7076168","identity":"rs-7076168","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}