Research Article

Evaluation of the Kasai Classification in Cystic Biliary Atresia Based on Intraoperative Findings: A Systematic Review of the Literature

Sebastian Forero-Escobedo¹*, Sandra Milena Gonzalez-Rodriguez¹ and Sebastian Sanchez-Tibaduiza²

¹Faculty of Medicine, National University of Colombia, Bogotá, Colombia

²Faculty of Medicine, University of Magdalena, Santa Marta, Colombia

Submission:April 18, 2025;Published:May 02, 2025

*Corresponding author:Sebastian Forero-Escobedo, Faculty of Medicine, National University of Colombia, Bogotá, Colombia.

How to cite this article:Sebastian Forero-E, Sandra Milena Gonzalez-R, Sebastian Sanchez-T. Evaluation of the Kasai Classification in Cystic Biliary Atresia Based on Intraoperative Findings: A Systematic Review of the Literature. Open Access J Surg. 2025; 16(4): 555941.DOI: 10.19080/OAJS.2025.16.555942.

Abstract

Introduction

Biliary Atresia is a congenital condition characterized by bile duct obstruction, leading to liver failure without timely intervention. The Kasai procedure is the standard treatment, but liver transplantation is often required. Current classifications do not fully address the complexity of cystic biliary atresia, a rare variant with unique features. This review proposes a new intraoperative-based classification to improve diagnosis and management.

Methods

A systematic review was conducted in November 2024 across PubMed, ScienceDirect, Scopus, Web of Science, and Google Scholar using the keywords “Cystic Biliary Atresia” OR “Biliary Atresia, Cystic.” The search followed PRISMA guidelines, with titles and abstracts screened by two authors and discrepancies resolved by a third. Included studies described preoperative and intraoperative findings of cystic biliary atresia. Articles lacking morphological data or full text were excluded.

Results

The review included 27 studies with 32 cases. Preoperative imaging identified cystic dilation in all cases, with hepatoportoenterostomy performed in 90.6%. Kasai type III predominated (78.1%), with subtype IIIb1 most frequent (53.1%). Cysts were located in the common bile duct (65.6%) or hepatic hilum (28.1%), with an average diameter of 1.9 cm. Findings revealed significant variability in cyst morphology and biliary communication.

Conclusion

Cyst biliary atresia is a rare and complex variant that challenges current classifications. While type III predominates, a more detailed classification is needed to address variability, improve diagnosis, and optimize outcomes.

Key words:Biliary Atresia; Cystic Biliary Atresia; Biliary Cyst; Choledochal Cyst; Kasai Procedure; Hepaticojejunostomy; Cholestasis

Abbreviations: BA: Biliary Atresia; HPE: Hepatoportoenterostomy; MKC: Modified Kasai Classification; IBA: Isolated Biliary Atresia; SBA: Syndromic Biliary Atresia; CBA: Cystic Biliary Atresia; CMVBA: Cytomegalovirus-associated Biliary Atresia

Introduction

Biliary Atresia (BA) is a progressive congenital disease characterized by sclerosing inflammation and obstruction of the intrahepatic and extrahepatic bile ducts, resulting in biliary flow stasis. Without timely treatment, it leads to progressive liver failure [1]. Its etiology is unknown and heterogeneous, exhibiting significant variability in the degree of destruction of the extrahepatic bile ducts [2]. The standard treatment for BA is hepatoportoenterostomy (HPE), also known as the Kasai procedure. This surgical technique involves the resection of the biliary remnants, the creation of a Roux-en-Y intestinal anastomosis, and the direct connection of the liver to the intestine to restore biliary flow. However, if the procedure fails or if the patient develops cirrhosis, liver transplantation becomes the definitive treatment [3]. Intervention after 60 days of life can accelerate liver fibrosis and significantly worsen outcomes [3,4]. BA is the most common cause of pediatric liver transplantation worldwide, accounting for approximately 50% of pediatric liver transplants in the United States, [5] 44% in Europe, and 54% in Australia and New Zealand [6,7]. According to the anatomical classification proposed by Kasai [8], BA is divided into four main types. Type I is characterized by partial or complete obstruction of the common bile duct. Type IIa involves obstruction of the common hepatic duct. Type IIb refers to obstruction of the common bile duct, the hepatic duct, and the cystic duct, without affecting the gallbladder. Type III, the most common, is characterized by obstruction of the bile ducts at the hilar level, with no macroscopically visible ducts in the biliary remnants of the hepatic porta. This type poses significant challenges for surgical management [9].

Years later, Kasai introduced a more detailed modification of this classification. The modified Kasai classification (MKC) is organized into three main levels: types, subtypes based on distal bile duct patterns, and subtypes based on hepatic branch patterns at the hepatic hilum. The primary types include Type I, corresponding to common bile duct atresia; Type II, involving hepatic duct atresia; and Type III, affecting the bile ducts at the hepatic hilum. Based on distal bile duct patterns, three categories are identified: patent common bile duct (a₁: patent common bile duct and atretic hepatic duct; a₂: patent common bile duct with aplasia of the hepatic duct); fibrous common bile duct (b₁: fibrous common bile duct with patent or atretic hepatic duct; b₂: fibrous common bile duct with hepatic duct aplasia); and absent common bile duct (c₁: absent common bile duct with patent or atretic hepatic duct; c₂: absent common bile duct with hepatic duct aplasia), in addition to miscellaneous patterns. Finally, the subtypes based on hepatic branch patterns at the hepatic hilum include: α, dilated hepatic branches (internal diameter >1 mm); β, hypoplastic hepatic branches (internal diameter ≤1 mm); γ, absence of bile duct; μ, fibrous hepatic branches; ν, fibrous mass; and ο, aplasia of hepatic branches [10].

In 2012, Davenport [11] introduced a clinical classification comprising four BA subtypes: isolated (IBA), syndromic (SBA), cystic (CBA), and cytomegalovirus-associated (CMVBA). Cystic biliary atresia (CBA) is a relatively rare variant, accounting for 5-10% of cases [1]. It is defined as cystic changes in an otherwise obliterated biliary tract, primarily located in the common hepatic duct or the common bile duct [12]. The typical diagnosis of BA generally includes ultrasound, HIDA scintigraphy, and cholangiography. Ultrasound has demonstrated 90% sensitivity in detecting gallbladder abnormalities associated with this condition. The triangular cord sign shows variable sensitivity ranging from 23% to 100%, while sensitivity for identifying cysts in the porta hepatis reaches 25%. [13]. Despite advances in current classifications, particularly the MKC in increasing detail, they fail to adequately capture the complexity of the cystic variant of BA, especially in cases with heterogeneous obliteration of the extrahepatic biliary tracts or functional gallbladders associated with cystic dilations. This study conducts a systematic review of the literature to analyze these morphological variants and proposes a new classification based on intraoperative findings, aiming to improve diagnostic accuracy and guide surgical management in this rare form of the disease.

Materials and Methods

In November 2024, a comprehensive bibliographic search was conducted across the PubMed, ScienceDirect, Scopus, Web of Science, and Google Scholar databases, using the keywords: “Cystic Biliary Atresia” OR “Biliary Atresia, Cystic”, with no restrictions on the publication year. Additionally, the references of included studies were manually reviewed to identify any potentially eligible studies. Full-text articles were accessed through institutional accounts with access to restricted resources, including journals and publishers with agreements with our institution. The study followed the PRISMA guidelines [14].

Articles retrieved were initially screened by title and abstract by two authors (F.E.S. and G.R.S.M) to assess their eligibility and inclusion potential. In cases of disagreement, a third investigator (S.T.S.) resolved the discrepancies through discussion and made the final decision. Subsequently, relevant full-text articles were reviewed for the investigation. Studies meeting the following criteria were selected: (1) Publications addressing cystic biliary atresia; (2) Case reports and case series; (3) Cases of patients with complete descriptions of preoperative and intraoperative morphological and anatomical characteristics; and (4) Studies involving human subjects. Articles were excluded if they were published in a language unknown to the authors, lacked an abstract in English, or did not provide access to the full text. Articles were also excluded if they did not include a complete morphological description or, at a minimum, diagnostic or surgical imaging figures that complemented the clinical case description and allowed the authors of this article to classify the cases into at least one subtype of the Kasai classification.

Results

A flow diagram (Figure 1) outlining the study selection process was created. The initial searches in electronic databases yielded a total of 907 studies, and 4 additional studies were manually retrieved from the reference lists of included studies. After removing duplicates, 684 studies remained and were thoroughly screened by title and abstract, with only 104 articles selected for full-text review. Following a full-text evaluation, 77 studies were excluded. We identified 27 studies that met the inclusion criteria for the systematic review, comprising a total of 32 patient cases. The characteristics of the patients from the included studies are presented in (Table 1). Thirty-two cases of patients with biliary atresia associated with extrahepatic cysts were analyzed. Patient ages at diagnosis or surgical intervention ranged from 4 to 126 days, with a mean of 46.2 days and a standard deviation of 28.4 days. The main reported symptoms included persistent jaundice, observed in 100% of cases (32/32), acholia in 87.5% (28/32), and hepatomegaly in 12.5% (4/32). Less frequent signs included palpable abdominal masses or acute abdominal distress. Preoperative findings identified cystic dilation at the hepatic hilum in 100% of cases (32/32). Ultrasound scans were widely utilized to visualize cystic lesions, while hepatobiliary scintigraphy (99mTc-IDA) demonstrated absent bile excretion in 75% of cases where it was performed (24/32).

Discussion

The presence of a cyst at the hepatic hilum, along with cholestasis, presents a critical differential diagnosis with choledochal cysts. Although both entities share some clinical features, they differ in etiology, progression, and treatment. Choledochal cyst dilation, also known as choledochal cyst, is a congenital malformation involving abnormal dilation of the bile ducts. Unlike biliary atresia, choledochal cysts are not exclusively neonatal diseases and are managed variably depending on the cyst type and presentation. Common variants often require resection followed by hepatoenterostomy [41]. Differentiating between these entities using imaging studies and intraoperative findings is crucial to prevent treatment delays, minimize the risk of advanced liver damage, and improve long-term outcomes [2].

The original and modified Kasai classifications were designed to describe conventional scenarios of biliary atresia, characterized by uniform obliteration of the bile ducts. These classifications are primarily based on the level of anatomical and functional disruption of the biliary system [42]. However, significant limitations arise when applying these classifications to more complex anatomical variants, such as biliary atresia with cystic dilations-a less common but clinically significant subtype in the differential diagnosis of persistent neonatal jaundice and cholestasis [43]. One of the main challenges is the inflexibility of current categories in addressing the presence of cystic structures. These dilations may be partially or entirely connected to the proximal or distal biliary system or may remain isolated [44]. This variability is inadequately addressed in current classifications, potentially leading to inaccurate or less clinically useful categorizations. Additionally, the Kasai classifications do not explicitly address the functionality of structures like the proximal bile duct, cystic duct, or gallbladder when they are adjacent to or connected with cystic dilations.

Biliary atresia type I accounts for approximately 5% of cases, type II for about 2%, and type III for more than 90% [45]. Our study observed a similar distribution, with type III being the most frequent, followed by type I and type II.

In cases of cystic biliary atresia, evaluating the biliary tree’s status is essential to characterize the distribution and drainage toward the dilations. This helps determine whether structures communicate with the bile ducts or are entirely isolated, potentially serving as a prognostic factor for severity. Cysts with proximal communication or patency have a lower likelihood of complete obliteration at the hilum and intrahepatic ducts, reducing the risk of hepatoportoenterostomy failure and the need for transplantation [46]. The Modified Kasai Classification subtypes present limitations in this regard, as they do not account for common anatomical combinations in these cases. Furthermore, they tend to detail less clinically relevant factors, such as fibrosis (μ), hypoplasia (β), narrowing (ο), or agenesis of intrahepatic ducts (γ), which are challenging to characterize surgically. At the same time, they superficially address more prevalent anatomical features, such as cysts at the junction of the cystic duct, common bile duct, and common hepatic duct, by integrating the patency or obliteration of the common hepatic duct into a single classification.

Applying these classifications to cases with cystic dilations was particularly challenging in this study. Differentiating between types like IIB and III based solely on intraoperative morphological data proved difficult. For example, during trans-cystic cholangiography (when the cystic duct is patent), contrast retention within the cyst may reflect complete or partial choledochal atresia but does not allow visualization of the hilum and intrahepatic ducts if the common hepatic duct is atritic or fibrotic only in its distal portion. In specific cases, preoperative studies such as hepatobiliary scintigraphy were also considered, evaluating bile flow from the parenchyma to the intrahepatic ducts and its passage through the hilum. We extend this as a recommendation to complement preoperative imaging studies upstream (from the liver to its hilum) with intraoperative assessments downstream (from the gallbladder through all proximal and distal extrahepatic ducts). These approaches could 1) more accurately characterize conventional atresia, and 2) describe the extent of atresia affecting the cyst-isolating segments.

Based on the morphological characteristics of the cystic dilations observed, we propose a new classification specific to cystic biliary atresia, aiming to simplify the description of patients and intraoperative findings based on extrahepatic biliary anatomy. (Table 2) outlines this classification and the patient distribution in this review. (Figure 2) illustrates the two primary criteria used to define this new typology: the location of the dilation concerning the cystic duct, the patency of the cystic duct, and the configuration of bile flow communication with the cyst. It is worth noting that in subtypes such as “b,” cholangiographic findings alone may be insufficient. Unlike the original Kasai classification, this new classification integrates surgical dissection findings, cholangiography, and novel intraoperative techniques, such as indocyanine green staining, to highlight biliary pathways downstream from the liver.

It is noteworthy that the frequency distribution of patients in CBA was significantly concentrated in subtype 2b, as this anatomical variation specifically complicates alignment with the original and modified Kasai classifications and the anatomical features we identified. It could be argued that the “a” subtypes of the new classification are fully explained by a distal obliterative process, which in most cases likely affects the common bile duct (Kasai I) (CBA 1, 2, or 3) or the common hepatic duct (Kasai IIa) (CBA 4). Both cases are easily distinguishable once patency is confirmed, and the cyst’s location is identified.

When observing a non-communicating cystic dilation, neither proximal nor distal to the midpoint of the biliary tract (between the hepatic and common bile ducts), the two apparent possibilities would be Kasai IIb or III atresias. However, this assumption is challenged due to the patency of the cystic duct, which, as described in other studies, is affected in these two forms of atresia. These atresias, theoretically of vertical extension, raise the question of whether they should be considered multiple atretic processes. It could be hypothesized that CBA 3b is more associated with Kasai III due to a more extensive obliterative process involving the extrahepatic biliary tract, likely related to congenital anomalies (given the involvement of the porta hepatis). On the other hand, CBA 2b may be more consistent with Kasai IIb due to the absence of involvement of the hepatic confluences and, consequently, possibly sparing the cystic duct in some cases. (Table 3) summarizes the patients classified as CBA 2b, grouped according to their previously assigned Kasai classification. To fully validate the findings of this study, it would be important to prospectively apply this classification to a larger cohort of neonates with cystic biliary atresia. This would enable consideration of the morphological and functional distributions described in this study from the initial clinical assessment of the patient.

Conclusion

Extrahepatic cyst-associated biliary atresia represents a complex and rare variant of the disease, posing challenges in both diagnosis and treatment. Despite advances in the Kasai classification, it is evident that these classifications do not fully capture the anatomical and functional variability of cases with cystic dilations, which could influence critical surgical decisions. The prevalence of biliary atresia types in this variant, with a clear predominance of type III, aligns with findings in previous studies but underscores the need for a more flexible and detailed classification to properly address differences in cyst characteristics, their connection to the biliary system, and their functionality. Accurate identification and classification of these cases are crucial to avoid misdiagnosis and treatment delays, which in turn could improve prognosis and reduce long-term hepatic complications.

Author Contribution

Forero Escobedo S conceptualized the study, contributed to data analysis and interpretation, drafted the manuscript, and approved the final version. Gonzalez Rodriguez SM contributed to data collection, data analysis, and manuscript drafting. Sanchez Tibaduiza S participated in the development of the methodology, data collection, and critical revision of the manuscript for intellectual content.

References

1. Lakshminarayanan B, Davenport M (2016) Biliary atresia: A comprehensive review. J Autoimmun 73: 1-9.
2. Madadi Sanjani O, Rohrbacher V, Uecker M (2024) Cystic Biliary Atresia a Single-Center, Retrospective Analysis. Dtsch Arztebl Int 121(19): 641-642.
3. Vij M, Rela M (2020) Biliary atresia: pathology, etiology and pathogenesis. Future Sci OA 6(5): 1-16.
4. Shin HJ, Yoon H, Han SJ, Ihn K, Koh H, et al. (2021) Key imaging features for differentiating cystic biliary atresia from choledochal cyst: prenatal ultrasonography and postnatal ultrasonography and MRI. Ultrasonography 40(2): 301-311.
5. Kelly DA, Bucuvalas JC, Alonso EM, Karpen SJ, Allen U, et al. (2013) Long-term medical management of the paediatric patient after liver transplantation: 2013 practice guideline by the American association for the study of liver diseases and the American society of transplantation. Liver Transplantation 19(8): 798-825.
6. Stormon MO, Hardikar W, Evans HM, Hodgkinson P (2020) Paediatric liver transplantation in Australia and New Zealand: 1985-2018. J Paediatr Child Health 56(11): 1739-1746.
7. Baumann U, Karam V, Adam R (2022) Prognosis of Children Undergoing Liver Transplantation: A 30-Year European Study. Paediatrics 150(4).
8. Kasai M (1974) Treatment of biliary atresia with special reference to hepatic Porto-enterostomy and its modifications. Progress in paediatric surgery 6: 50-52.
9. Nakamura H, Murase N, Koga H, Cazares J, Lane GJ, et al. (2016) Classification of biliary atresia in the laparoscopic era. Pediatr Surg Int 32(12): 1209-1212.
10. Davenport M (2012) Biliary atresia: clinical aspects. Semin Pediatr Surg 21(3): 175-84.
11. Brandon G O’Connor DO, Richard B Towbin MD, Carrie M Schaefer MD, Alexander J Towbin MD (2024) Cystic Biliary Atresia. Appl Rad Oncol (5): 3-6.
12. Zhou W, Zhou L (2021) Ultrasound for the Diagnosis of Biliary Atresia: From Conventional Ultrasound to Artificial Intelligence. Diagnostics (Basel) 12(1): 1-14.
13. Page MJ, McKenzie JE, Bossuyt PM, Bourton I, Hoffmann TC et al. (2021) The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. BMJ 372(71): 1-9.
14. Tsuchida Y, Kawarasaki H, Iwanaka T, Uchida H, Nakanishi H, et al. (1995) Antenatal diagnosis of biliary atresia (type I cyst) at 19 weeks' gestation: differential diagnosis and etiologic implications. J Pediatr Surg 30(5): 697-699.
15. Matsubara H, Oya N, Suzuki Y, Kajiura S, Suzumori K, et al. (1997) Is it possible to differentiate between choledochal cyst and congenital biliary atresia (type I cyst) by antenatal ultrasonography? Fetal Diagn Ther 12(5): 306-308.
16. Takahashi A, Tsuchida Y, Hatakeyama S, Suzuki N, Kuroiwa M, et al. (1997) A peculiar form of multiple cystic dilatations of the intrahepatic biliary system found in a patient with biliary atresia. J Pediatr Surg 32(12): 1776-1779.
17. Iwai N, Deguchi E, Sasaki Y, Idoguchi K, Yanagihara J (1999) Antenatal diagnosis of biliary atresia (noncorrect able cyst type): a case report. Eur J Pediatr Surg 9(5): 340-342.
18. Shiono S, Yamagiwa I, Obata K, Okuyama N, Ouchi T, et al. (2000) A case of biliary atresia with cystic dilatation of the extrahepatic bile duct and polysplenia syndrome. Pediatr Surg Int 16(8): 599-601.
19. Casaccia G, Bilancioni E, Nahom A, Trucchi A, Aite L, et al. (2002) Cystic anomalies of biliary tree in the foetus: is it possible to make a more specific prenatal diagnosis? J Pediatr Surg 37(8): 1191-1194.
20. De Matos V, Erlichman J, Russo PA, Haber BA (2005) Does "cystic" biliary atresia represent a distinct clinical and etiological subgroup? A series of three cases. Pediatr Dev Pathol 8(6): 725-731.
21. Sookpotarom P, Vejchapipat P (2007) Non-correctable biliary atresia with large extrahepatic cyst: a report of two cases. Eur J Pediatr Surg 17(4): 295-297.
22. Obaidah A, Dhende NP, Mane SB, Acharya H (2009) Biliary atresia associated with choledochal cyst. Afr J Paediatr Surg 6(1): 61-62.
23. Nori M, Venkateshwarlu J, Vijay Sekhar, Prasad GR (2013) Extrahepatic biliary atresia with choledochal cyst: Prenatal MRI predicted and post natally confirmed: A case report. Indian J Radiol Imaging 23(3): 238-242.
24. Adewole VA, Wright NJ, Hallows R, Davenport M (2014) Antenatally detected cystic biliary atresia: differential diagnoses of a double bubble. Springer plus 19(3): 1-5.
25. Parra D, Fecteau A, Daneman A (2016) Findings in percutaneous cholangiography in two cases of Type III cystic biliary atresia (with ultrasound correlation). BJR Case Rep 2(2): 1-3.
26. Schooler GR, Mavis A (2018) Cystic biliary atresia: A distinct clinical entity that may mimic choledochal cyst. Radiol Case Rep 13(2): 415-418.
27. Sakamoto N, Muraji T, Masumoto K, Yanai T, Ono K (2018) Intrahepatic biliary cyst after a Kasai procedure. J Pediatr Surg Case Rep 31: 32-35.
28. Koshinaga T, Ohashi K, Ono K, Kaneda H, Furuya T (2018) Obliterative cholangiopathy in acquired cystic biliary atresia type III after cyst perforation: a case report. BMC Pediatr 18(1): 1-7.
29. Azna AA, Hayati F, Azizan N, Che Noh CI, Osman M (2018) Cystic biliary atresia: A delayed diagnosis of obstructive jaundice. Turkiye Klinikleri J Case Rep 26(2): 102-104.
30. Kimura T, Hirabayashi T, Ishido K, Kobayashi T, Saito T, et al. (2018) Biliary atresia with cystic dilatation of the common bile duct. J Pediatr Surg Case Rep 38: 16-18.
31. Masui D, Fukahori S, Mizuochi T, Watanabe Y, Fukui K, et al. (2019) Cystic biliary atresia with paucity of bile ducts and gene mutation in KDM6A: a case report. Surg Case Rep 5(1): 1-6.
32. Nandan R, Jana M, Yadav DK, Goel P (2021) Cystic biliary atresia with congenital absence of portal vein. BMJ Case Rep 14(1): 1-4.
33. Berkowitz CL, Peters AW, Stratigis JD, Barone PD, Kadenhe Chiweshe AV, et al. (2021) Cystic biliary anomaly in a newborn with features of choledochal cyst and cystic biliary atresia. J Pediatr Surg Case Rep 66: 1-4.
34. Prata R, Nunes A, Borges C, Soares E (2021) Cystic biliary atresia: an uncommon variant of biliary atresia in which a gallbladder may be present. Eurorad Case Pp: 1-8.
35. Kunwar S, BC B, Sah RK (2021) Biliary Atresia with Extrahepatic Cyst: A Diagnostic Dilemma. Cureus 13(8): 1-6.
36. Reuland C, Cappiello CD (2021) Cystic biliary atresia masquerading as a choledochal cyst. J Pediatr Surg Case Rep 74: 1-5.
37. Rahamtalla D, Al Rawahi Y, Jawa ZM, Wali Y (2022) Cystic biliary atresia in a neonate with antenatally detected abdominal cyst. BMJ Case Rep 15(2): 1-3.
38. Lee NW, Karim NKA, Singh PSD (2023) A rare case of cystic biliary atresia. Malays J Med Health Sci 19(3): 380-382.
39. Wang M, Liao J, Li S, Zhang S, Huang J (2023) Laparoscopic indocyanine green fluorescence imaging technique in rare type II cystic biliary atresia. Photodiagnosis Photodyn Ther Pp: 44.
40. Issenman J, Martin K (2025) Common bile duct cysts in neonates, not always a choledochal cyst: A case report. J Pediatr Surg Case Rep 112: 1-5.
41. Yamataka A, Ohshiro K, Okada Y, Hosoda Y, Fujiwara T, et al. (1997) Complications after cyst excision with hepatic enterostomy for choledochal cysts and their surgical management in children versus adults. J Pediatr Surg 32(7): 1097-1102.
42. Sasaki H, Nio M, Ando H, Kitagawa H, Kubota M, et al. (2021) Anatomical patterns of biliary atresia including hepatic radicles at the porta hepatis influence short- and long-term prognoses. Journal of hepato-biliary-pancreatic sciences 28(11): 931-941.
43. Fischler B, Papadogiannakis N, Nemeth A (2001) Aetiological factors in neonatal cholestasis. Acta paediatric (Oslo, Norway: 1992) 90(1): 88-92.
44. Lobeck IN, Sheridan R, Lovell M, Dupree P, Tiao GM, et al. (2017) Cystic Biliary Atresia and Choledochal Cysts Are Distinct Histopathologic Entities. The American journal of surgical pathology 41(3): 354-364.
45. Hartley JL, Davenport M, Kelly DA (2009) Biliary atresia. Lancet 374(9702): 1704-1713.
46. Asai A, Wu JF, Wang KS, Yamataka A, Nio M, et al. (2022) The Outcome of Patients with Cystic Biliary Atresia with Intact Proximal Hepatic Ducts Following Hepatic-Cyst-Jejunostomy. Journal of paediatric gastroenterology and nutrition 75(2): 131-137.