A Cautionary Tale of Anatomical Variations of the Extrahepatic Biliary System and Their Implications for Surgical Procedures: A Systematic Literature Review

A Cautionary Tale of Anatomical Variations of the Extrahepatic Biliary System and Their Implications for Surgical Procedures: A Systematic Literature Review | 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 Systematic Review A Cautionary Tale of Anatomical Variations of the Extrahepatic Biliary System and Their Implications for Surgical Procedures: A Systematic Literature Review Andrew Chiagozie Ekwesianya, Boluwatife Oladapo Ayantunde, Abraham Ayantunde This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6368119/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 24 May, 2025 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted 10 You are reading this latest preprint version Abstract Background The hepatobiliary system has the most associated anatomical variations in the body and they are a direct reflection of the complexity of its embryological development. The anatomical pattern commonly described as ‘normal’ occurs only in 57–72% of the population. The objective of the study is to review the English Language published literature on the prevalence of the anatomical extra-hepatic biliary system variations and their potential implications for surgical and endoscopic procedures. This will assist both practicing and trainee surgeons in preventing biliary tract injuries while operating in this area. Methodology A comprehensive literature search was conducted using the PICO framework across SCOPUS, PubMed, MEDLINE, and Cochrane databases. Study characteristics and relevant data were collated. The prevalence of the most clinically important anatomical variations is presented. Results Seventy studies, encompassing 17,207 subjects, were included: 27 studies (9,738 subjects) on cystic duct variations, 17 studies (2,633 subjects) on gallbladder variations, and 26 studies (4,836 subjects) on cystic artery variations. Notable findings include low insertion (11.2%), medial insertion (9.8%), and parallel course (7.4%) of the cystic duct, Hartmann’s pouch in 12.2% of gallbladders, and the cystic artery originating from the right hepatic artery in 83.6% or other sources in 16.4%. Moynihan’s hump of the right hepatic artery was found in 1.8%. Conclusion These variations are frequent and surgically relevant. Understanding them is critical to avoiding complications. Employing the critical view of safety in laparoscopic cholecystectomy ensures proper visualization of anatomical structures, reducing the risk of injury. Anatomical variations cystic artery cystic duct gallbladder bile duct biliary tract accessory anomaly aberrant extrahepatic Figures Figure 1 INTRODUCTION Anatomical variations are differences in the arrangement and location of structures compared to the normal anatomy. They are due to the normal margin of error seen in the topography and morphology of body structures, caused by aberrations of embryologic developmental timing, and the persistence of normally obliterated structures. They differ from major congenital anomalies which are structural deformities that involve defects in or damage to a developing foetus with usually adverse physiological and anatomical dysfunction [ 1 ]. Most variations are totally benign, and this makes it difficult to accurately estimate the incidence of some of the more common variations. The biliary system starts at bile canaliculi between hepatocytes that coalesce into interlobular biliary ducts in the interlobular portal triad. These in turn unite to form the intrahepatic collecting bile ducts in the intrahepatic portal triad [ 2 ]. These merge to form the left and right hepatic ducts that exit the liver to form the common hepatic duct. The common hepatic duct is joined by the cystic duct from the gallbladder to form the common bile duct, which is 5.5cm − 15cm in length [ 3 ]. The arterial supply of the hepatobiliary system is derived from the common hepatic artery, a branch of the coeliac artery. After giving off the gastroduodenal artery, the common hepatic artery continues as the proper hepatic artery, which later divides into the right and left hepatic arteries that supply the respective anatomic lobe of the liver. The cystic artery is usually a direct branch of the right hepatic artery. A named cystic vein does not normally exist: venous blood from the gallbladder drains directly to the liver via the gallbladder fossa and hepatocystic triangle [ 4 ]. The hepatocystic triangle of Calot is an anatomical landmark important for cholecystectomy. It is bounded medially by the common hepatic duct, laterally by the cystic duct and superiorly by the inferior border of the liver. This triangle usually contains the cystic artery, cystic lymph node of Lund, lymphatics and connective tissues [ 5 ]. The development of the liver and biliary system is a complex process that can lead to several anatomical variations. These are based on studies using cadaveric dissections, resin casts, direct surgical observations, and radiologic contrast studies. Due to the enhanced magnification provided by the endoscopic lens, the advent of laparoscopic surgery has afforded a better appreciation of the anatomical variations of the hepatobiliary apparatus better than radiological images and cadaveric dissections. The hepatobiliary system has the most associated anatomical variations in the body and they are a direct reflection of the complexity of its embryological development [ 6 – 8 ]. The hepatobiliary and pancreatic systems embryologically begin their development early in the fourth week of gestation through a complex process of cell budding and fusion from the ventral part of the distal foregut, which affords numerous opportunities for variations to the normal [ 9 ]. The anatomical variant that is termed “normal” occurs only in about 57–72% of people [ 10 – 12 ]. The anatomical variations of the extra-hepatic biliary system, although not significantly life-threatening like other anatomical variations or congenital malformations, have significant clinical implications especially during surgical procedures. Generally, non-recognition and/or misidentification of normal anatomy and/or anatomical variations have been shown to contribute to the occurrence of major perioperative complications, especially biliary tract injuries [ 13 ]. As a result, awareness of the prevalence and the pattern of these variations in the general population may significantly help prevent inadvertent injuries during surgical and endoscopic procedures [ 7 , 8 , 13 ]. The critical view of safety is the final view that is obtained after dissection of the hepatocystic triangle during laparoscopic cholecystectomy. Achievement of this involves complete dissection of the hepatocystic triangle, dissection of the inferior third of the cystic plate, and identification of only two structures entering the gallbladder – the cystic duct and cystic artery. Given that preoperative cross-sectional radiological assessment of the biliary anatomy is not routinely performed in all patients, the critical view is a proven safe method of delineating the anatomy of the hepatocystic triangle to identify these important structures and their variations, and thus prevent unintended biliovascular injuries [ 14 ]. The purpose of this paper is to review the English language published literature on the prevalence of these anatomical variations of the extra-hepatic biliary system and discuss their potential implications for surgical procedures. This will assist both practicing and aspiring surgeons in preventing biliary tract injuries while operating in this area. Previous systematic reviews and meta-analyses have been done by anatomists but they focused exclusively on anatomical variations of the cystic artery [ 15 , 16 ]. Our review additionally includes variations of the cystic duct and gallbladder and provides more in-depth discussion of their implications for surgical procedures. METHODS Search strategy and eligibility criteria The literature search on the anatomical variations of the extrahepatic biliary system was performed on MEDLINE, PubMed, SCOPUS, and The Cochrane Work Trials Register under the Cochrane Central Register of Controlled Trials (CENTRAL), using the PICO framework. The keywords used were ‘anatomical variations’ in combination with ‘cystic artery’, ‘cystic duct’, ‘gallbladder’, ‘biliary tree’, ‘biliary system’, ‘bile duct’, ‘biliary tract’, ‘accessory’, ‘anomaly’, ‘ectopic’, ‘aberrant’, ‘absent’, ‘atresia’, and ‘extrahepatic’. All relevant English language publications up to November 2024 were identified, with data extracted from the studies if they were deemed appropriate to this review of the existing literature on extrahepatic biliary system variations. The references of the identified articles were also searched to identify further relevant articles. Selection process Two of the authors independently evaluated all of the studies discovered using the keywords and deemed them appropriate for inclusion or exclusion via multiple screening processes. This included ensuring that the articles were in the English language. An additional search was performed and all selected articles reviewed by the third author for compliance with the inclusion criteria. Data collection process At the first screening, titles were scrutinised and any studies demonstrating a lack of relevance were excluded. Such lack of relevance included anatomical variations of regions beyond the extra-hepatic biliary tree, clinical trials for pharmaceuticals and interventions, and animal studies. To ensure high sensitivity of the search, uncertain items were not excluded, but subjected to a second screen. The second screen was performed by reading the abstracts of items that were not excluded at the first screen. The criteria mentioned above were used for the abstracts too. Additionally, all case reports, case series and comparative studies not reporting anatomical variation results were excluded because determination of prevalence from these reports is not reliable. Studies not reporting original data including reviews and comments were also excluded. Finally the remaining articles were subjected to a third screen. Full papers of all remaining items were collected and read. Only studies that focused on the anatomical variations of the extra-hepatic biliary tree and had accompanying numerical data were selected for this analysis. Synthesis methods Data were extracted from all the eligible studies, presented in tables and charts. Analysis was done using IBM SPSS Statistics package, version 29.0.1.0. RESULTS Study selection and study characteristics A total of 1,192 articles were retrieved following a search on the medical databases. Duplicate data, articles that did not deal specifically on variations of the human extrahepatic biliovascular anatomy, case reports and studies without specific data on the desired variations, were excluded. Figure 1 shows the PRISMA flow chart of the systematic literature search. A total of 70 studies, spanning from 1947 to 2024, and comprising 17,207 subjects were selected for this systematic review: 27 studies on cystic duct variations comprising 9,738 subjects, 17 studies on gallbladder variations comprising 2,633 subjects, and 26 studies on the anatomical variations of the cystic artery consisting of 4,836 subjects. The anatomical variations were studied based on dissections of the biliary anatomy of human cadaveric specimens, radiological studies of the biliary system, and intraoperative dissections during cholecystectomy procedures. Cystic duct variations The study characteristics and distributions of the common cystic duct variations are shown in Tables I and II of the Appendix. The cystic duct drains bile from the gallbladder, forms the lower border of the hepatocystic triangle and joins the extrahepatic biliary duct at its lateral border. The most common variations of the cystic duct are posterior insertion (29.4%) and high insertion (14.0%) of the cystic duct into the extrahepatic bile, as shown in Table 1 . Table 1 Prevalence of cystic duct variations. CD – Cystic Duct; LHD – Left Hepatic Duct CD Variation Frequency Total Number of Subjects Prevalence (%) High insertion 473 3382 14.0 Anterior insertion 418 5490 7.6 Posterior insertion 1586 5390 29.4 Long CD 99 3795 2.6 CD from LHD 6 2185 0.3 Accessory CD 14 1537 0.9 Absent CD 1 230 0.4 Subvesical bile ducts (Ducts of Luschka) 132 5626 2.3 Double CD 7 1444 0.5 Table 2 illustrates the prevalence of the most surgically significant cystic duct variations: low insertion (11.2%), medial insertion (9.8%), parallel course of the cystic duct (7.4%), insertion into the right hepatic duct (1.1%), and short cystic duct (3.2%). CD Variation Frequency Total Number of Subjects Prevalence (%) Low insertion 668 5976 11.2 Medial insertion 563 5774 9.8 Parallel course 209 2841 7.4 Insertion into RHD 44 4159 1.1 Short CD 167 5218 3.2 Table 2 : Prevalence of cystic duct variations with the most surgical implications. CD – Cystic Duct; RHD – Right Hepatic Duct Gallbladder variations Table III of the Appendix outlines the study characteristics and morphological features of commonly described variations of the gallbladder. Prevalence of the most clinically significant external morphological variations of the gallbladder is outlined in Table 3 . Presence of the Hartmann’s pouch, an outpouching on the ventral surface just proximal to the neck (infundibulum) of the gallbladder, is the most common morphological variation, occurring in 12.2% of the population. Table 3 Prevalence of gallbladder variations. GB – gallbladder. Gallbladder Variation Frequency Total Number of Subjects Prevalence (%) Intrahepatic GB 27 1206 2.2 Floating GB 4 1099 0.4 Hartmann's pouch 90 737 12.2 Phrygian cap 29 1526 1.9 Folded neck 15 290 5.2 GB duplication 4 242 1.7 Cystic Artery Variations The study characteristics and variations in the origin of the cystic artery are shown in Table IV of the Appendix. The cystic artery normally arises (83.6%) as a branch of the right hepatic artery within the hepatocystic triangle, courses towards the gallbladder superomedial to the cystic duct. At the medial border of the body of the gallbladder, the cystic artery divides into a smaller superficial branch that supplies the anterior surface of the gallbladder, and a larger deep branch that runs in the gallbladder bed to supply the posterior surface of the gallbladder. The prevalence of the variations of the cystic artery origin is shown in Table 4 . Double cystic artery, in which one artery arises from the right hepatic artery and the other from another vessel outside the hepatocystic triangle, or both arteries arise from the right hepatic artery, is prevalent in 10.0% of the population. Table 4 Prevalence of anatomical variations in the origin of the cystic artery Table V of the Appendix illustrates the study characteristics and variations in the course of the cystic artery in relation to the hepatocystic triangle and the cystic duct. When the cystic artery arises from the right hepatic artery outside of the hepatocystic triangle, it courses either in front (14.9%) or behind (45.9%) the common hepatic duct, as shown in Table 5 . The Caterpillar hump occurs in 1.8% of the pooled subjects. Cystic artery coursing completely outside the hepatocystic triangle occurs in 14.0% of the study population. Arterial Origin Frequency Total Number of Subjects Prevalence (%) Right Hepatic Artery 4043 4836 83.6 Aberrant Right Hepatic Artery 193 3246 5.9 Left Hepatic Artery 117 3554 3.3 Proper Hepatic Artery 46 1290 3.6 Common Hepatic Artery 73 1964 3.7 Gastroduodenal Artery 154 3370 4.6 Superior Pancreaticoduodenal Artery 3 1172 0.3 Parenchyma of Liver 25 1200 2.1 Double Cystic Artery 332 3328 10.0 Absent Cystic Artery 28 4836 0.6 Table 5 Prevalence of anatomical variations of the course of the cystic artery Anatomical Variation Frequency Total Number of Subjects Prevalence (%) Caterpillar Hump RHA 22 1200 1.8 Anterior to CD 113 1768 6.4 Posterior to CD 33 996 3.3 Anterior to CHD 284 1908 14.9 Posterior to CHD 876 1908 45.9 Outside of Callot's Triangle 378 2692 14.0 DISCUSSION A good knowledge of the anatomical variations of the hepatobiliary system is important in cholecystectomy and other hepatobiliary procedures such as living donor liver transplant surgery, endoscopic interventional procedures and endovascular surgery [ 17 ]. Variations in the level of insertion of the cystic duct into the bile duct can affect and alter the hepatocystic triangle and have implications during laparoscopic cholecystectomy. The bile duct, from the confluence of the hepatic ducts to the ampulla of Vater, is anatomically divided into three equal parts. A normal insertion of the cystic duct is to the lateral aspect of the middle third of this extrahepatic bile duct. Insertion of the cystic duct in the upper third of the bile duct is termed a high insertion, while insertion in the lower third is described as a low insertion [ 18 ]. Variations of the cystic duct that, if not recognised, are associated with increased risk of intraoperative biliary duct injury include low insertion, medial insertion and insertion into the right hepatic duct [ 19 ]. In our study, low insertion occurred in 11.2%, medial insertion occurred in 9.8% and insertion into the right hepatic duct in 1.1%. In the case of a medial insertion, the cystic duct courses anterior or posterior to the bile duct to insert on its medial border. In some cases, it courses down parallel to the bile duct for > 2 cm before inserting on its medial border, a situation described as parallel course of the cystic duct [ 20 ]. In our study, parallel course occurs in 7.4% of the population. Our findings are similar to those of Sarawagi et al [ 19 ], who reported low insertion to be prevalent in 9% and parallel course of the cystic duct in 7.5% of their study population. Low insertion of the cystic duct may also pose technical challenges during ERCP and increase the risk of complications [ 21 ]. The cystic duct normally empties into the common hepatic duct. A variation that results in the duct connecting with the right hepatic duct, or less commonly the left hepatic duct, can result in distortion of the hepatocystic triangle and so increase the risk of inadvertent biliary injury. A double cystic duct may not only cause anatomical confusion during cholecystectomy but can also result in bile leak postoperatively, especially if not recognised and clipped appropriately. The length of the cystic duct is variable, with an average of 2cm − 4cm. There is no standardised definition of a short cystic duct in the literature; however, most authors define it as a cystic duct < 5mm in length [ 22 , 23 ]. There is an increased risk of bile duct injury while clipping a short cystic duct during laparoscopic cholecystectomy. Adatepe et al, in their review of MRCP images of 1,041 patients reported a short cystic duct to be present in 0.38%, long cystic duct in 0.38% and medial insertion of the cystic duct in 7.3% of their patients [ 22 ]. This is lower than the figures in our study in which short and long cystic ducts are present in 3.2% and 2.6%, respectively, and medial insertion of the duct in 9.8%. The observed differences may be due to differences in the study population and the techniques of assessing the biliary anatomy. While Adatepe and colleagues carried out their study among the Turkish population using MRCP images, our study is a pooled analysis of several studies from different ethnic populations and based on radiological, cadaveric and surgical assessments of the biliary anatomy. Subvesical bile ducts, also called the ducts of Luschka, are ducts that drain bile from the right hepatic lobe through the gallbladder fossa directly to the gallbladder, bypassing the hepatic ducts. In our pooled analysis, the prevalence of the presence of ducts of Luschka is 2.3%. The clinical importance of this variation is that failure to recognise, ligate or clip these ducts during cholecystectomy could result in postoperative bile leak and biloma formation [ 24 ]. Variations of the gallbladder can be internal or external. Internal variations such as septate gallbladder have little surgical significance and so are not included in this study. External variations, however, are much more clinically significant and include intrahepatic gallbladder (2.2%), floating gallbladder (0.4%), duplications of the gallbladder (1.7%), and presence of morphological features such as Phrygian cap (1.9%), Hartmann’s pouch (12.2%) and a folded neck (5.2%). There are few reports of gallbladder hypoplasia [ 25 ], or a complete congenital absence (agenesis) of the gallbladder, but these are mainly malformations and are very rare. Presence of a Hartmann’s pouch has been found to be associated with an increased risk of gallstone formation [ 26 ]. Excruciating biliary colic can occur if a stone is impacted in the Hartmann’s pouch. Though uncommon, an impacted stone within an inflamed Hartmann’s pouch may adhere to the common bile duct, causing extrinsic compression of the duct, a phenomenon called the Mirizzi syndrome [ 27 ]. The pouch is also important for lateral traction on the gallbladder to expose and allow dissection of the hepatocystic triangle [ 28 ]. Unlike Hartmann’s pouch, the Phrygian cap – an infolding of the fundus of the gallbladder – has less clinical significance and occurs in 1.9% of our study population. A floating gallbladder is one that is completely covered in peritoneum and suspended by a mesentery between the gallbladder and the liver; it can result in torsion around the cystic duct pedicle [ 29 ]. An intrahepatic gallbladder, on the contrary, is buried within the gallbladder fossa of the liver and can result in significant liver bleeding during cholecystectomy. Intrahepatic gallbladder does not completely empty its bile and the biliary stasis increases the risk of stone formation and cholecystitis [ 30 ]. The normal origin of the cystic artery is from the right hepatic artery. Variations outside of this origin may affect the location of the cystic artery relative to the hepatocystic triangle and thus increase the risk of complications during cholecystectomy. In our study, variations of the artery’s origin include aberrant right hepatic artery (5.9%), left hepatic artery (3.3%), proper hepatic artery (3.6%), common hepatic artery (3.7%), gastroduodenal artery (4.6%), superior pancreaticoduodenal artery (0.3%), and the liver parenchyma (2.1%). Origin from the superior mesenteric artery is also reported in literatures but this was not assessed in this study. The variations of the cystic artery have been classified into three groups by Suzuki et al [ 31 ]. In this classic description, group 1 category have the cystic artery entirely within the hepatocystic triangle and no other source of supply to the gallbladder is seen. This could be further divided into group 1a (single cystic artery) and group 1b (double cystic artery) within the hepatocystic triangle. In group 2 pattern, there is more than one cystic artery – one artery originating from the right hepatic artery and coursing through the hepatocystic triangle as usual, while the other (aberrant) artery originates elsewhere and courses entirely outside the triangle. In group 3, one or more cystic arteries are present but they are located outside the hepatocystic triangle in both origin and course; no artery to the gallbladder is seen on dissection of the triangle. Suzuki and colleagues reported the normal pattern of a single cystic artery in the hepatocystic triangle in 76.6%, a double cystic artery in 11.1%, and cystic artery outside of the triangle in 11.1%. In our pooled analysis, a single cystic artery arising from the right hepatic artery and traversing the hepatocystic triangle is present in 83.6%, double cystic artery in 10.0%, and cystic artery coursing entirely outside the triangle in 14.0%. The clinical significance is that poor knowledge of the existence of these significantly common variations could result in intraoperative arterial bleed, with the risk that injury to other hepatobiliary structures could occur. In group 2 variants, ligation of the normal cystic artery without control of the aberrant artery arising outside the hepatocystic triangle could result in unanticipated haemorrhage. Similarly, absence of an artery following dissection of the triangle should prompt a search for supply of the gallbladder outside the triangle, otherwise injury to these extra-Calot’s arteries could occur during dissection of the gallbladder. The Moynihan’s hump (also called a caterpillar turn) is an abnormal configuration of the right hepatic artery in which it takes a tortuous course anterior to the cystic duct and comes close to the gallbladder. The surgical significance is that, due to its proximity to the cystic duct and gallbladder, the tortuous right hepatic artery could be injured during dissection of the hepatocystic triangle. It could also be mistaken for the cystic artery and clipped during cholecystectomy. This could result in significant intraoperative bleeding (due to improper clipping of such a large vessel). Obfuscation of the surgical field will increase the risk of injury to other structures of the hepatobiliary apparatus. A complete clipping of the Moynihan’s hump will also impair the blood supply of the right hepatic lobe and result in ischaemia. In our study, Moynihan’s hump is present in 1.8%. Asghar et al, in their meta-analysis of 8,418 subjects, determined the prevalence of Moynihan’s hump to be 3.81% [ 32 ]. Suspicion of the presence of the Moynihan’s hump should be raised when the cystic artery is unusually short or the right hepatic artery is tortuous. Gentle lateral traction of the infundibulum of the gallbladder and careful dissection to achieve the critical view of safety are necessary to prevent vascular accidents. The limitations of our study include the fact that the primary studies used for the analysis were heterogeneous in terms of study population, methods of assessment of the biliary anatomy, and study design. Secondly, exclusion of other studies not published in the English language would mean that not all studies that reported anatomical variations of the extrahepatic biliary apparatus have been captured in this review. In addition, the exclusion of case reports might have affected the computed prevalence of rarer anatomical variations, such as gallbladder hypoplasia, that are mostly presented as case reports. CONCLUSION Variations of the anatomy of the extrabiliary apparatus are common and these have implications for surgical procedures. A good understanding of these variations is important to prevent unintended injuries during procedures in this area. Achievement of the critical view of safety during laparoscopic cholecystectomy would ensure that relevant anatomical structures are adequately delineated and variations visualised before structures are clipped or divided. Declarations Competing interests No competing interest declared. Author Contribution All authors made substantial contributions to the design, literature search, data collation and analysis . ACE and BOA drafted the manuscript, and this was reviewed by AA who made significant intellectual input. All authors approved the final version to be published. All authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. 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Nepal Med Coll J 9(4):286–288. https://pubmed.ncbi.nlm.nih.gov/18298024/ Suzuki M, Akaishi S, Rikiyama T, Naitoh T, Rahman MM, Matsuno S (2000) Laparoscopic cholecystectomy, Calot's triangle, and variations in cystic arterial supply. Surg Endosc 14(2):141–144. 10.1007/s004649900086 Asghar A, Priya A, Patra A, Gupta P, Kumar A (2023) Moynihan's hump of the right hepatic artery in Calot's triangle: a systematic review and meta-analysis of its incidence and surgical importance. Surg Radiol Anat 45(5):643–651. 10.1007/s00276-023-03125-8 Additional Declarations No competing interests reported. Supplementary Files AppendixAnatomicalvariations.docx Cite Share Download PDF Status: Published Journal Publication published 24 May, 2025 Read the published version in Surgical and Radiologic Anatomy → Version 1 posted Editorial decision: Revision requested 17 Apr, 2025 Reviews received at journal 17 Apr, 2025 Reviewers agreed at journal 16 Apr, 2025 Reviews received at journal 13 Apr, 2025 Reviewers agreed at journal 08 Apr, 2025 Reviewers agreed at journal 08 Apr, 2025 Reviewers invited by journal 08 Apr, 2025 Editor assigned by journal 07 Apr, 2025 Submission checks completed at journal 05 Apr, 2025 First submitted to journal 03 Apr, 2025 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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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-6368119","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Systematic Review","associatedPublications":[],"authors":[{"id":440285910,"identity":"3cf1c80b-33c3-45a2-80c4-aba051d43121","order_by":0,"name":"Andrew Chiagozie Ekwesianya","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFElEQVRIiWNgGAWjYHACAzhxAETwg4iEAlK0SDaAtBgQqQXCPYDKxwD8s5u3ffjYZmNscLz94YGfOw7LG59fnfjhgQGDPL/YAaxaJO4cK545sy3NzODMGYODvWcOG2678XazBNBhhjNnJ2C35kaOMTPvtsM2ZjdyGA7wth1m3Hbj7AaQlgSD29i1yIO0/N3238bs/vMHB/+2HbbfPOPs5h/4tBiAtDBuO2BmdoPB4DDQlsQN/L3b8NpieCOtmLH3X7Kx/Zkcg8OybenJM27wbrNIMJDA6Re5G8mbGX6csTOc2X788ce3bda2/f1nN9/8UWEjzy+Nw/tooBkYiGCVEkQpB4E6YFQdIFr1KBgFo2AUjAwAAIg4a8K1lL1FAAAAAElFTkSuQmCC","orcid":"","institution":"Southend University Hospital NHS Foundation Trust","correspondingAuthor":true,"prefix":"","firstName":"Andrew","middleName":"Chiagozie","lastName":"Ekwesianya","suffix":""},{"id":440285911,"identity":"bb8d03cf-31c4-4ba9-8e4d-7493b2438437","order_by":1,"name":"Boluwatife Oladapo Ayantunde","email":"","orcid":"","institution":"Norfolk and Norwich University Hospitals NHS Foundation Trust","correspondingAuthor":false,"prefix":"","firstName":"Boluwatife","middleName":"Oladapo","lastName":"Ayantunde","suffix":""},{"id":440285912,"identity":"8e827ace-a02c-44d5-92c2-a14faaa0de22","order_by":2,"name":"Abraham Ayantunde","email":"","orcid":"","institution":"Southend University Hospital NHS Foundation Trust","correspondingAuthor":false,"prefix":"","firstName":"Abraham","middleName":"","lastName":"Ayantunde","suffix":""}],"badges":[],"createdAt":"2025-04-03 09:53:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6368119/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6368119/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00276-025-03660-6","type":"published","date":"2025-05-24T15:57:29+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":80293142,"identity":"27520f6d-6d3d-4beb-8ee1-593d05a15b43","added_by":"auto","created_at":"2025-04-10 08:14:06","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":507627,"visible":true,"origin":"","legend":"\u003cp\u003ePRISMA 2020 flow diagram for updated systematic reviews which include searches of databases and registers\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6368119/v1/9f3e2e3f288a10404590acb2.jpeg"},{"id":83460166,"identity":"8efb2128-849b-4bb3-b21a-ef8176959dc6","added_by":"auto","created_at":"2025-05-26 16:11:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1331495,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6368119/v1/f9633c52-70d5-42e6-9e09-aa3e7fdc0d57.pdf"},{"id":80293145,"identity":"53a32cde-8d26-4635-934a-c2f4a84e156b","added_by":"auto","created_at":"2025-04-10 08:14:06","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":85838,"visible":true,"origin":"","legend":"","description":"","filename":"AppendixAnatomicalvariations.docx","url":"https://assets-eu.researchsquare.com/files/rs-6368119/v1/4801853649f30fee39932fef.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Cautionary Tale of Anatomical Variations of the Extrahepatic Biliary System and Their Implications for Surgical Procedures: A Systematic Literature Review","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eAnatomical variations are differences in the arrangement and location of structures compared to the normal anatomy. They are due to the normal margin of error seen in the topography and morphology of body structures, caused by aberrations of embryologic developmental timing, and the persistence of normally obliterated structures. They differ from major congenital anomalies which are structural deformities that involve defects in or damage to a developing foetus with usually adverse physiological and anatomical dysfunction [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Most variations are totally benign, and this makes it difficult to accurately estimate the incidence of some of the more common variations.\u003c/p\u003e \u003cp\u003eThe biliary system starts at bile canaliculi between hepatocytes that coalesce into interlobular biliary ducts in the interlobular portal triad. These in turn unite to form the intrahepatic collecting bile ducts in the intrahepatic portal triad [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. These merge to form the left and right hepatic ducts that exit the liver to form the common hepatic duct. The common hepatic duct is joined by the cystic duct from the gallbladder to form the common bile duct, which is 5.5cm \u0026minus;\u0026thinsp;15cm in length [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe arterial supply of the hepatobiliary system is derived from the common hepatic artery, a branch of the coeliac artery. After giving off the gastroduodenal artery, the common hepatic artery continues as the proper hepatic artery, which later divides into the right and left hepatic arteries that supply the respective anatomic lobe of the liver. The cystic artery is usually a direct branch of the right hepatic artery. A named cystic vein does not normally exist: venous blood from the gallbladder drains directly to the liver via the gallbladder fossa and hepatocystic triangle [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe hepatocystic triangle of Calot is an anatomical landmark important for cholecystectomy. It is bounded medially by the common hepatic duct, laterally by the cystic duct and superiorly by the inferior border of the liver. This triangle usually contains the cystic artery, cystic lymph node of Lund, lymphatics and connective tissues [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe development of the liver and biliary system is a complex process that can lead to several anatomical variations. These are based on studies using cadaveric dissections, resin casts, direct surgical observations, and radiologic contrast studies. Due to the enhanced magnification provided by the endoscopic lens, the advent of laparoscopic surgery has afforded a better appreciation of the anatomical variations of the hepatobiliary apparatus better than radiological images and cadaveric dissections.\u003c/p\u003e \u003cp\u003eThe hepatobiliary system has the most associated anatomical variations in the body and they are a direct reflection of the complexity of its embryological development [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The hepatobiliary and pancreatic systems embryologically begin their development early in the fourth week of gestation through a complex process of cell budding and fusion from the ventral part of the distal foregut, which affords numerous opportunities for variations to the normal [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The anatomical variant that is termed \u0026ldquo;normal\u0026rdquo; occurs only in about 57\u0026ndash;72% of people [\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe anatomical variations of the extra-hepatic biliary system, although not significantly life-threatening like other anatomical variations or congenital malformations, have significant clinical implications especially during surgical procedures. Generally, non-recognition and/or misidentification of normal anatomy and/or anatomical variations have been shown to contribute to the occurrence of major perioperative complications, especially biliary tract injuries [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. As a result, awareness of the prevalence and the pattern of these variations in the general population may significantly help prevent inadvertent injuries during surgical and endoscopic procedures [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe critical view of safety is the final view that is obtained after dissection of the hepatocystic triangle during laparoscopic cholecystectomy. Achievement of this involves complete dissection of the hepatocystic triangle, dissection of the inferior third of the cystic plate, and identification of only two structures entering the gallbladder \u0026ndash; the cystic duct and cystic artery. Given that preoperative cross-sectional radiological assessment of the biliary anatomy is not routinely performed in all patients, the critical view is a proven safe method of delineating the anatomy of the hepatocystic triangle to identify these important structures and their variations, and thus prevent unintended biliovascular injuries [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe purpose of this paper is to review the English language published literature on the prevalence of these anatomical variations of the extra-hepatic biliary system and discuss their potential implications for surgical procedures. This will assist both practicing and aspiring surgeons in preventing biliary tract injuries while operating in this area.\u003c/p\u003e \u003cp\u003ePrevious systematic reviews and meta-analyses have been done by anatomists but they focused exclusively on anatomical variations of the cystic artery [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Our review additionally includes variations of the cystic duct and gallbladder and provides more in-depth discussion of their implications for surgical procedures.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSearch strategy and eligibility criteria\u003c/h2\u003e \u003cp\u003eThe literature search on the anatomical variations of the extrahepatic biliary system was performed on MEDLINE, PubMed, SCOPUS, and The Cochrane Work Trials Register under the Cochrane Central Register of Controlled Trials (CENTRAL), using the PICO framework. The keywords used were \u0026lsquo;anatomical variations\u0026rsquo; in combination with \u0026lsquo;cystic artery\u0026rsquo;, \u0026lsquo;cystic duct\u0026rsquo;, \u0026lsquo;gallbladder\u0026rsquo;, \u0026lsquo;biliary tree\u0026rsquo;, \u0026lsquo;biliary system\u0026rsquo;, \u0026lsquo;bile duct\u0026rsquo;, \u0026lsquo;biliary tract\u0026rsquo;, \u0026lsquo;accessory\u0026rsquo;, \u0026lsquo;anomaly\u0026rsquo;, \u0026lsquo;ectopic\u0026rsquo;, \u0026lsquo;aberrant\u0026rsquo;, \u0026lsquo;absent\u0026rsquo;, \u0026lsquo;atresia\u0026rsquo;, and \u0026lsquo;extrahepatic\u0026rsquo;. All relevant English language publications up to November 2024 were identified, with data extracted from the studies if they were deemed appropriate to this review of the existing literature on extrahepatic biliary system variations. The references of the identified articles were also searched to identify further relevant articles.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSelection process\u003c/h3\u003e\n\u003cp\u003eTwo of the authors independently evaluated all of the studies discovered using the keywords and deemed them appropriate for inclusion or exclusion via multiple screening processes. This included ensuring that the articles were in the English language. An additional search was performed and all selected articles reviewed by the third author for compliance with the inclusion criteria.\u003c/p\u003e\n\u003ch3\u003eData collection process\u003c/h3\u003e\n\u003cp\u003eAt the first screening, titles were scrutinised and any studies demonstrating a lack of relevance were excluded. Such lack of relevance included anatomical variations of regions beyond the extra-hepatic biliary tree, clinical trials for pharmaceuticals and interventions, and animal studies. To ensure high sensitivity of the search, uncertain items were not excluded, but subjected to a second screen.\u003c/p\u003e \u003cp\u003eThe second screen was performed by reading the abstracts of items that were not excluded at the first screen. The criteria mentioned above were used for the abstracts too. Additionally, all case reports, case series and comparative studies not reporting anatomical variation results were excluded because determination of prevalence from these reports is not reliable. Studies not reporting original data including reviews and comments were also excluded.\u003c/p\u003e \u003cp\u003eFinally the remaining articles were subjected to a third screen. Full papers of all remaining items were collected and read. Only studies that focused on the anatomical variations of the extra-hepatic biliary tree and had accompanying numerical data were selected for this analysis.\u003c/p\u003e\n\u003ch3\u003eSynthesis methods\u003c/h3\u003e\n\u003cp\u003eData were extracted from all the eligible studies, presented in tables and charts. Analysis was done using IBM SPSS Statistics package, version 29.0.1.0.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStudy selection and study characteristics\u003c/h2\u003e \u003cp\u003eA total of 1,192 articles were retrieved following a search on the medical databases. Duplicate data, articles that did not deal specifically on variations of the human extrahepatic biliovascular anatomy, case reports and studies without specific data on the desired variations, were excluded. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the PRISMA flow chart of the systematic literature search.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA total of 70 studies, spanning from 1947 to 2024, and comprising 17,207 subjects were selected for this systematic review: 27 studies on cystic duct variations comprising 9,738 subjects, 17 studies on gallbladder variations comprising 2,633 subjects, and 26 studies on the anatomical variations of the cystic artery consisting of 4,836 subjects. The anatomical variations were studied based on dissections of the biliary anatomy of human cadaveric specimens, radiological studies of the biliary system, and intraoperative dissections during cholecystectomy procedures.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eCystic duct variations\u003c/h3\u003e\n\u003cp\u003eThe study characteristics and distributions of the common cystic duct variations are shown in Tables I and II of the Appendix. The cystic duct drains bile from the gallbladder, forms the lower border of the hepatocystic triangle and joins the extrahepatic biliary duct at its lateral border. The most common variations of the cystic duct are posterior insertion (29.4%) and high insertion (14.0%) of the cystic duct into the extrahepatic bile, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePrevalence of cystic duct variations. CD \u0026ndash; Cystic Duct; LHD \u0026ndash; Left Hepatic Duct\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCD Variation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFrequency\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTotal Number of Subjects\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePrevalence (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHigh insertion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e473\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3382\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior insertion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e418\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5490\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior insertion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1586\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5390\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e29.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLong CD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3795\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCD from LHD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2185\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAccessory CD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1537\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAbsent CD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e230\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubvesical bile ducts\u003c/p\u003e \u003cp\u003e(Ducts of Luschka)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e132\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5626\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDouble CD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1444\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eillustrates the prevalence of the most surgically significant cystic duct variations: low insertion (11.2%), medial insertion (9.8%), parallel course of the cystic duct (7.4%), insertion into the right hepatic duct (1.1%), and short cystic duct (3.2%).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCD Variation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFrequency\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTotal Number of Subjects\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePrevalence (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLow insertion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e668\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5976\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e11.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMedial insertion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e563\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5774\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e9.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParallel course\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e209\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2841\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e7.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsertion into RHD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4159\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShort CD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e167\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5218\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e: \u003cb\u003ePrevalence of cystic duct variations with the most surgical implications. CD \u0026ndash; Cystic Duct; RHD \u0026ndash; Right Hepatic Duct\u003c/b\u003e\u003c/p\u003e\n\u003ch3\u003eGallbladder variations\u003c/h3\u003e\n\u003cp\u003eTable III of the Appendix outlines the study characteristics and morphological features of commonly described variations of the gallbladder. Prevalence of the most clinically significant external morphological variations of the gallbladder is outlined in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Presence of the Hartmann\u0026rsquo;s pouch, an outpouching on the ventral surface just proximal to the neck (infundibulum) of the gallbladder, is the most common morphological variation, occurring in 12.2% of the population.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePrevalence of gallbladder variations. GB \u0026ndash; gallbladder.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGallbladder Variation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFrequency\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTotal Number of Subjects\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePrevalence (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntrahepatic GB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1206\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFloating GB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1099\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHartmann's pouch\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e737\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e12.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhrygian cap\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1526\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFolded neck\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e290\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGB duplication\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e242\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eCystic Artery Variations\u003c/h2\u003e \u003cp\u003eThe study characteristics and variations in the origin of the cystic artery are shown in Table IV of the Appendix. The cystic artery normally arises (83.6%) as a branch of the right hepatic artery within the hepatocystic triangle, courses towards the gallbladder superomedial to the cystic duct. At the medial border of the body of the gallbladder, the cystic artery divides into a smaller superficial branch that supplies the anterior surface of the gallbladder, and a larger deep branch that runs in the gallbladder bed to supply the posterior surface of the gallbladder.\u003c/p\u003e \u003cp\u003eThe prevalence of the variations of the cystic artery origin is shown in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Double cystic artery, in which one artery arises from the right hepatic artery and the other from another vessel outside the hepatocystic triangle, or both arteries arise from the right hepatic artery, is prevalent in 10.0% of the population.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003ePrevalence of anatomical variations in the origin of the cystic artery\u003c/b\u003e Table V of the Appendix illustrates the study characteristics and variations in the course of the cystic artery in relation to the hepatocystic triangle and the cystic duct. When the cystic artery arises from the right hepatic artery outside of the hepatocystic triangle, it courses either in front (14.9%) or behind (45.9%) the common hepatic duct, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. The Caterpillar hump occurs in 1.8% of the pooled subjects. Cystic artery coursing completely outside the hepatocystic triangle occurs in 14.0% of the study population.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eArterial Origin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFrequency\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTotal Number of Subjects\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePrevalence (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRight Hepatic Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4043\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4836\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e83.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAberrant Right Hepatic Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e193\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3246\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e5.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft Hepatic Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e117\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3554\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProper Hepatic Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1290\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCommon Hepatic Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1964\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGastroduodenal Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3370\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior Pancreaticoduodenal Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1172\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParenchyma of Liver\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDouble Cystic Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e332\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3328\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e10.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAbsent Cystic Artery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4836\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePrevalence of anatomical variations of the course of the cystic artery\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnatomical Variation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFrequency\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTotal Number of Subjects\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePrevalence (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCaterpillar Hump RHA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior to CD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e113\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1768\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior to CD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e996\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnterior to CHD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e284\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1908\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePosterior to CHD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e876\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1908\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e45.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOutside of Callot's Triangle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e378\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2692\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e14.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eA good knowledge of the anatomical variations of the hepatobiliary system is important in cholecystectomy and other hepatobiliary procedures such as living donor liver transplant surgery, endoscopic interventional procedures and endovascular surgery [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eVariations in the level of insertion of the cystic duct into the bile duct can affect and alter the hepatocystic triangle and have implications during laparoscopic cholecystectomy. The bile duct, from the confluence of the hepatic ducts to the ampulla of Vater, is anatomically divided into three equal parts. A normal insertion of the cystic duct is to the lateral aspect of the middle third of this extrahepatic bile duct. Insertion of the cystic duct in the upper third of the bile duct is termed a high insertion, while insertion in the lower third is described as a low insertion [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eVariations of the cystic duct that, if not recognised, are associated with increased risk of intraoperative biliary duct injury include low insertion, medial insertion and insertion into the right hepatic duct [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In our study, low insertion occurred in 11.2%, medial insertion occurred in 9.8% and insertion into the right hepatic duct in 1.1%. In the case of a medial insertion, the cystic duct courses anterior or posterior to the bile duct to insert on its medial border. In some cases, it courses down parallel to the bile duct for \u0026gt;\u0026thinsp;2 cm before inserting on its medial border, a situation described as parallel course of the cystic duct [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In our study, parallel course occurs in 7.4% of the population. Our findings are similar to those of Sarawagi et al [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], who reported low insertion to be prevalent in 9% and parallel course of the cystic duct in 7.5% of their study population. Low insertion of the cystic duct may also pose technical challenges during ERCP and increase the risk of complications [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe cystic duct normally empties into the common hepatic duct. A variation that results in the duct connecting with the right hepatic duct, or less commonly the left hepatic duct, can result in distortion of the hepatocystic triangle and so increase the risk of inadvertent biliary injury.\u003c/p\u003e \u003cp\u003eA double cystic duct may not only cause anatomical confusion during cholecystectomy but can also result in bile leak postoperatively, especially if not recognised and clipped appropriately.\u003c/p\u003e \u003cp\u003eThe length of the cystic duct is variable, with an average of 2cm \u0026minus;\u0026thinsp;4cm. There is no standardised definition of a short cystic duct in the literature; however, most authors define it as a cystic duct\u0026thinsp;\u0026lt;\u0026thinsp;5mm in length [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. There is an increased risk of bile duct injury while clipping a short cystic duct during laparoscopic cholecystectomy.\u003c/p\u003e \u003cp\u003eAdatepe et al, in their review of MRCP images of 1,041 patients reported a short cystic duct to be present in 0.38%, long cystic duct in 0.38% and medial insertion of the cystic duct in 7.3% of their patients [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. This is lower than the figures in our study in which short and long cystic ducts are present in 3.2% and 2.6%, respectively, and medial insertion of the duct in 9.8%. The observed differences may be due to differences in the study population and the techniques of assessing the biliary anatomy. While Adatepe and colleagues carried out their study among the Turkish population using MRCP images, our study is a pooled analysis of several studies from different ethnic populations and based on radiological, cadaveric and surgical assessments of the biliary anatomy.\u003c/p\u003e \u003cp\u003eSubvesical bile ducts, also called the ducts of Luschka, are ducts that drain bile from the right hepatic lobe through the gallbladder fossa directly to the gallbladder, bypassing the hepatic ducts. In our pooled analysis, the prevalence of the presence of ducts of Luschka is 2.3%. The clinical importance of this variation is that failure to recognise, ligate or clip these ducts during cholecystectomy could result in postoperative bile leak and biloma formation [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eVariations of the gallbladder can be internal or external. Internal variations such as septate gallbladder have little surgical significance and so are not included in this study. External variations, however, are much more clinically significant and include intrahepatic gallbladder (2.2%), floating gallbladder (0.4%), duplications of the gallbladder (1.7%), and presence of morphological features such as Phrygian cap (1.9%), Hartmann\u0026rsquo;s pouch (12.2%) and a folded neck (5.2%). There are few reports of gallbladder hypoplasia [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], or a complete congenital absence (agenesis) of the gallbladder, but these are mainly malformations and are very rare.\u003c/p\u003e \u003cp\u003ePresence of a Hartmann\u0026rsquo;s pouch has been found to be associated with an increased risk of gallstone formation [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Excruciating biliary colic can occur if a stone is impacted in the Hartmann\u0026rsquo;s pouch. Though uncommon, an impacted stone within an inflamed Hartmann\u0026rsquo;s pouch may adhere to the common bile duct, causing extrinsic compression of the duct, a phenomenon called the Mirizzi syndrome [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The pouch is also important for lateral traction on the gallbladder to expose and allow dissection of the hepatocystic triangle [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Unlike Hartmann\u0026rsquo;s pouch, the Phrygian cap \u0026ndash; an infolding of the fundus of the gallbladder \u0026ndash; has less clinical significance and occurs in 1.9% of our study population.\u003c/p\u003e \u003cp\u003eA floating gallbladder is one that is completely covered in peritoneum and suspended by a mesentery between the gallbladder and the liver; it can result in torsion around the cystic duct pedicle [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. An intrahepatic gallbladder, on the contrary, is buried within the gallbladder fossa of the liver and can result in significant liver bleeding during cholecystectomy. Intrahepatic gallbladder does not completely empty its bile and the biliary stasis increases the risk of stone formation and cholecystitis [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe normal origin of the cystic artery is from the right hepatic artery. Variations outside of this origin may affect the location of the cystic artery relative to the hepatocystic triangle and thus increase the risk of complications during cholecystectomy. In our study, variations of the artery\u0026rsquo;s origin include aberrant right hepatic artery (5.9%), left hepatic artery (3.3%), proper hepatic artery (3.6%), common hepatic artery (3.7%), gastroduodenal artery (4.6%), superior pancreaticoduodenal artery (0.3%), and the liver parenchyma (2.1%). Origin from the superior mesenteric artery is also reported in literatures but this was not assessed in this study.\u003c/p\u003e \u003cp\u003eThe variations of the cystic artery have been classified into three groups by Suzuki et al [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. In this classic description, group 1 category have the cystic artery entirely within the hepatocystic triangle and no other source of supply to the gallbladder is seen. This could be further divided into group 1a (single cystic artery) and group 1b (double cystic artery) within the hepatocystic triangle. In group 2 pattern, there is more than one cystic artery \u0026ndash; one artery originating from the right hepatic artery and coursing through the hepatocystic triangle as usual, while the other (aberrant) artery originates elsewhere and courses entirely outside the triangle. In group 3, one or more cystic arteries are present but they are located outside the hepatocystic triangle in both origin and course; no artery to the gallbladder is seen on dissection of the triangle.\u003c/p\u003e \u003cp\u003eSuzuki and colleagues reported the normal pattern of a single cystic artery in the hepatocystic triangle in 76.6%, a double cystic artery in 11.1%, and cystic artery outside of the triangle in 11.1%. In our pooled analysis, a single cystic artery arising from the right hepatic artery and traversing the hepatocystic triangle is present in 83.6%, double cystic artery in 10.0%, and cystic artery coursing entirely outside the triangle in 14.0%.\u003c/p\u003e \u003cp\u003eThe clinical significance is that poor knowledge of the existence of these significantly common variations could result in intraoperative arterial bleed, with the risk that injury to other hepatobiliary structures could occur. In group 2 variants, ligation of the normal cystic artery without control of the aberrant artery arising outside the hepatocystic triangle could result in unanticipated haemorrhage. Similarly, absence of an artery following dissection of the triangle should prompt a search for supply of the gallbladder outside the triangle, otherwise injury to these extra-Calot\u0026rsquo;s arteries could occur during dissection of the gallbladder.\u003c/p\u003e \u003cp\u003eThe Moynihan\u0026rsquo;s hump (also called a caterpillar turn) is an abnormal configuration of the right hepatic artery in which it takes a tortuous course anterior to the cystic duct and comes close to the gallbladder. The surgical significance is that, due to its proximity to the cystic duct and gallbladder, the tortuous right hepatic artery could be injured during dissection of the hepatocystic triangle. It could also be mistaken for the cystic artery and clipped during cholecystectomy. This could result in significant intraoperative bleeding (due to improper clipping of such a large vessel). Obfuscation of the surgical field will increase the risk of injury to other structures of the hepatobiliary apparatus. A complete clipping of the Moynihan\u0026rsquo;s hump will also impair the blood supply of the right hepatic lobe and result in ischaemia.\u003c/p\u003e \u003cp\u003eIn our study, Moynihan\u0026rsquo;s hump is present in 1.8%. Asghar et al, in their meta-analysis of 8,418 subjects, determined the prevalence of Moynihan\u0026rsquo;s hump to be 3.81% [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Suspicion of the presence of the Moynihan\u0026rsquo;s hump should be raised when the cystic artery is unusually short or the right hepatic artery is tortuous. Gentle lateral traction of the infundibulum of the gallbladder and careful dissection to achieve the critical view of safety are necessary to prevent vascular accidents.\u003c/p\u003e \u003cp\u003eThe limitations of our study include the fact that the primary studies used for the analysis were heterogeneous in terms of study population, methods of assessment of the biliary anatomy, and study design. Secondly, exclusion of other studies not published in the English language would mean that not all studies that reported anatomical variations of the extrahepatic biliary apparatus have been captured in this review. In addition, the exclusion of case reports might have affected the computed prevalence of rarer anatomical variations, such as gallbladder hypoplasia, that are mostly presented as case reports.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eVariations of the anatomy of the extrabiliary apparatus are common and these have implications for surgical procedures. A good understanding of these variations is important to prevent unintended injuries during procedures in this area. Achievement of the critical view of safety during laparoscopic cholecystectomy would ensure that relevant anatomical structures are adequately delineated and variations visualised before structures are clipped or divided.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eNo competing interest declared.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors made substantial contributions to the design, literature search, data collation and analysis . ACE and BOA drafted the manuscript, and this was reviewed by AA who made significant intellectual input. All authors approved the final version to be published. All authors agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe research data and references listed in the Appendix as supplementary file\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eOTHER INFORMATION\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSupport\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo external support was received for this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKachl\u0026iacute;k D, Varga I, B\u0026aacute;ča V, Musil V (2020) Variant Anatomy and Its Terminology. 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Surg Endosc 14(2):141\u0026ndash;144. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s004649900086\u003c/span\u003e\u003cspan address=\"10.1007/s004649900086\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAsghar A, Priya A, Patra A, Gupta P, Kumar A (2023) Moynihan's hump of the right hepatic artery in Calot's triangle: a systematic review and meta-analysis of its incidence and surgical importance. Surg Radiol Anat 45(5):643\u0026ndash;651. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00276-023-03125-8\u003c/span\u003e\u003cspan address=\"10.1007/s00276-023-03125-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Anatomical variations, cystic artery, cystic duct, gallbladder, bile duct, biliary tract, accessory, anomaly, aberrant, extrahepatic","lastPublishedDoi":"10.21203/rs.3.rs-6368119/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6368119/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThe hepatobiliary system has the most associated anatomical variations in the body and they are a direct reflection of the complexity of its embryological development. The anatomical pattern commonly described as \u0026lsquo;normal\u0026rsquo; occurs only in 57\u0026ndash;72% of the population. The objective of the study is to review the English Language published literature on the prevalence of the anatomical extra-hepatic biliary system variations and their potential implications for surgical and endoscopic procedures. This will assist both practicing and trainee surgeons in preventing biliary tract injuries while operating in this area.\u003c/p\u003e\u003ch2\u003eMethodology\u003c/h2\u003e \u003cp\u003eA comprehensive literature search was conducted using the PICO framework across SCOPUS, PubMed, MEDLINE, and Cochrane databases. Study characteristics and relevant data were collated. The prevalence of the most clinically important anatomical variations is presented.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eSeventy studies, encompassing 17,207 subjects, were included: 27 studies (9,738 subjects) on cystic duct variations, 17 studies (2,633 subjects) on gallbladder variations, and 26 studies (4,836 subjects) on cystic artery variations. Notable findings include low insertion (11.2%), medial insertion (9.8%), and parallel course (7.4%) of the cystic duct, Hartmann\u0026rsquo;s pouch in 12.2% of gallbladders, and the cystic artery originating from the right hepatic artery in 83.6% or other sources in 16.4%. Moynihan\u0026rsquo;s hump of the right hepatic artery was found in 1.8%.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThese variations are frequent and surgically relevant. Understanding them is critical to avoiding complications. Employing the critical view of safety in laparoscopic cholecystectomy ensures proper visualization of anatomical structures, reducing the risk of injury.\u003c/p\u003e","manuscriptTitle":"A Cautionary Tale of Anatomical Variations of the Extrahepatic Biliary System and Their Implications for Surgical Procedures: A Systematic Literature Review","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-10 08:14:01","doi":"10.21203/rs.3.rs-6368119/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-17T18:04:47+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-17T11:48:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"118343282054554091968372799000689787069","date":"2025-04-16T15:27:23+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-13T07:31:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"12527787490322985712085837306545587692","date":"2025-04-08T20:42:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"18546294782671885765456438886486997110","date":"2025-04-08T06:24:59+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-08T05:39:05+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-04-07T05:56:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-04-05T09:20:13+00:00","index":"","fulltext":""},{"type":"submitted","content":"Surgical and Radiologic Anatomy","date":"2025-04-03T09:45:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"surgical-and-radiologic-anatomy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sara","sideBox":"Learn more about [Surgical and Radiologic Anatomy](http://link.springer.com/journal/276)","snPcode":"276","submissionUrl":"https://submission.nature.com/new-submission/276/3","title":"Surgical and Radiologic Anatomy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"cd25bf56-5652-4aec-9aae-7ab482e25f64","owner":[],"postedDate":"April 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-05-26T16:05:28+00:00","versionOfRecord":{"articleIdentity":"rs-6368119","link":"https://doi.org/10.1007/s00276-025-03660-6","journal":{"identity":"surgical-and-radiologic-anatomy","isVorOnly":false,"title":"Surgical and Radiologic Anatomy"},"publishedOn":"2025-05-24 15:57:29","publishedOnDateReadable":"May 24th, 2025"},"versionCreatedAt":"2025-04-10 08:14:01","video":"","vorDoi":"10.1007/s00276-025-03660-6","vorDoiUrl":"https://doi.org/10.1007/s00276-025-03660-6","workflowStages":[]},"version":"v1","identity":"rs-6368119","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6368119","identity":"rs-6368119","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}