Association between anatomic variations of extrahepatic and intrahepatic bile ducts: Do look up!

Biliary anatomic variations are usually asymptomatic, but they may cause problems in diagnostic investigations and interventional and surgical procedures, increasing both their technical difficulty and their postoperative complication rates. The aim of the present study was to evaluate the prevalence of anatomic variations in the intrahepatic biliary ducts (IHBD) in relation to demographical and clinical characteristics in a large study population requiring magnetic resonance cholangiopancreatography (MRCP) for various clinical conditions. The possible association between IHBD and extrahepatic biliary ducts (EHBD) variants was then explored. From January 2017 to May 2019, 1004 patients underwent MRCP. Demographical and clinical data were collected. IHBD and EHBD anatomy were recorded and the EHBD anatomy was classified using both qualitative and quantitative classifications. The presence of a type 3 EHBD variant (an abnormal proximal cystic duct [CD] insertion) in both qualitative and quantitative classifications and an intrapancreatic CD were associated with the presence of IHBD variants at univariate analysis (p = 0.008, p = 0.019, and p = 0.001, respectively). The presence of a posterior or medial insertion of the CD into the EHBD was a strong predictive factor of the presence of IHBD variants both at uni- and multivariate analysis (p = 0.002 and p = 0.003 for posterior insertion and p = 0.002 and p = 0.002 for medial insertion, respectively). The presence of gallstones on MRCP resulted in a strong predictor of the presence of an anatomical variant of the IHBD both at uni- and multivariate analysis (p = 0.027 and p = 0.046, respectively). In conclusion, the presence of a type 3 variant of the EHBD, an intrapancreatic CD and, especially, a posterior/medial CD insertion into the EHBD represent predictive factors of the concomitant presence of IHBD variants, thus radiologists must be vigilant when encountering these EHBD configurations and always remember to "look up" at the IHBD. Finally, the presence of an IHBD variant is a strong predictive factor of gallstones.

Variations in extra-hepatic biliary tree morphology and morphometry: a narrative review of literature with focus on cystohepatic triangle

The morphometry and morphology of the components of extrahepatic biliary tree show extensive variations. A beforehand recognition of these variations is very crucial to prevent unintended complications while performing surgeries in this region. This study was conducted to analyse the configuration of the extrahepatic biliary tree and its possible variations, as well as measure the components that limit the cystohepatic triangle. Articles were searched in major online indexed databases (Medline and PubMed, Scopus, Embase, CINAHL Plus, Web of Science and Google Scholar) using relevant key words. A total of 73 articles matched the search criteria of which 55 articles were identified for data extraction. The length of left and right hepatic duct in majority of studies was found to be > 10 mm. A wide range of diameters of hepatic ducts were observed between 5 and 43 mm. The average length of cystic duct is around 20 mm. The length and diameter of the common bile duct are 50-150 mm and 3-9 mm, respectively. The most frequently observed pattern of insertion of cystic duct into common hepatic duct is right lateral, rarely anterior, or posterior spiral insertion can present. The results of this study will provide a standard reference range which instead will help to differentiate the normal and pathological conditions.

A Technique to Define Extrahepatic Biliary Anatomy Using Robotic Near-Infrared Fluorescent Cholangiography

BACKGROUND

Bile duct injury is a rare but serious complication of minimally invasive cholecystectomy. Traditionally, intraoperative cholangiogram has been used in difficult cases to help delineate anatomical structures, however, new imaging modalities are currently available to aid in the identification of extrahepatic biliary anatomy, including near-infrared fluorescent cholangiography (NIFC) using indocyanine green (ICG).1-5 The objective of the study was to evaluate if this technique may aid in safe dissection to obtain the critical view.

METHODS

Thirty-five consecutive multiport robotic cholecystectomies using NIFC with ICG were performed using the da Vinci Firefly Fluorescence Imaging System. All patients received 2.5 mg ICG intravenously at the time of intubation, followed by patient positioning, draping, and establishment of pneumoperitoneum. No structures were divided until the critical view of safety was achieved. Real-time toggling between NIFC and bright-light illumination was utilized throughout the case to define the extrahepatic biliary anatomy.

RESULTS

ICG was successfully administered to all patients without complication, and in all cases the extrahepatic biliary anatomy was able to be identified in real-time 3D. All procedures were completed without biliary injury, conversion to an open procedure, or need for traditional cholangiography to obtain the critical view. Specific examples of cases where x-ray cholangiography or conversion to open was avoided and NIFC aided in safe dissection leading to the critical view are demonstrated, including (1) evaluation for aberrant biliary anatomy, (2) confirmation of non-biliary structures, and (3) use in cases where the infundibulum is fused to the common bile duct.

CONCLUSION

NIFC using ICG is demonstrated as a useful technique to rapidly identify and aid in the visualization of extrahepatic biliary anatomy. Techniques that selectively utilize this technology specifically in difficult cases where the anatomy is unclear are demonstrated in order to obtain the critical view of safety.

Ancient Greek Terminology in Hepatopancreatobiliary Anatomy and Surgery

Most of the terminology in medicine originates from Greek or Latin, revealing the impact of the ancient Greeks on modern medicine. However, the literature on the etymology of Greek words used routinely in medical practice is sparse. We provide a short guide to the etymology and meaning of Greek words currently used in the field of hepatopancreatobiliary (HPB) anatomy and surgery. Focusing on HPB medical literature, the etymology and origin of Greek words including suffixes and prefixes are shown and analyzed. For example, anatomy (anatomia) is a Greek word derived from the prefix ana- (on, upon) and the suffix -tomy from the verb temno meaning to cut. Surgery, however, is not a Greek word. The corresponding Greek word is chirourgiki derived from cheir (hand) and ergon (action, work) meaning the action made by hands. Understanding the root of Greek terminology leads to an accurate, precise and comprehensive scientific medical language, reflecting the need for a universal medical language as a standardized means of communication within the health care sector.

[Construction of a three-dimensional visualization model of arteries supplying the extrahepatic bile duct based on submillimeter CT data]

OBJECTIVE

To construct a three-dimensional (3D) model of arteries supplying the extrahepatic bile duct with a new segmentation algorithm based on submillimeter CT data.

METHODS

The new image segmentation algorithm based on interactive volume rendering was integrated into Medical Image Three-Dimensional Visualization System (MI-3DVS) as an intersected plug-in. The abdominal submillimeter CTA data of 10 patients were imported into MI-3DVS and the 3D model of the extrahepatic bile duct and its supplying arteries were constructed. The 3D model was zoomed in, zoomed out and spinned for observation and analysis of the arteries supplying the extrahepatic bile duct.

RESULTS

The 3D models of the blood supply to extrahepatic bile duct allowed stereoscopic, and accurate display of the fourth- and fifth-level branches of the hepatic artery, the second-level branches of the cystic artery, the pancreatic duodenal artery arch and the retroportal artery. The 3D models also provided a clear vision of the biliary structures including the hepatobiliary tract, the left and right hepatic ducts, gallbladder, the liver duct, and the common bile duct.

CONCLUSION

Based on the segmentation method of interactive volume rendering, the CT data of the arterioles supplying the extrahepatic bile duct can be extracted and segmented for 3D reconstruction to display the three-dimensional anatomical structures of the extrahepatic bile duct and its supplying arteries.

Anatomical variations and congenital anomalies of extra hepatic biliary system encountered during laparoscopic cholecystectomy

OBJECTIVE

To assess the frequency of anatomical variations of extrahepatic biliary system in patients undergoing laparoscopic cholecystectomy.

METHODS

This is an observational study performed in the Department of Surgery, Liaquat University of Medical and Health Sciences, Jamshoro for a period of four years from January 2004 to December 2007. All diagnosed patients of cholelithiasis undergoing routine laparoscopic cholecystectomy were assessed for anatomical/congenital extra hepatic biliary and vascular anomalies. Structures mainly assessed for anomalies were gall bladder, cystic duct, supraduodenal part of Common Bile Duct (CBD), cystic artery and hepatic artery which are routinely handled during laparoscopy. However, assessment of variations and anomalies, of hepatic ducts, portal vein, retroduodenal and pancreatic parts of CBD were not done due to possibility of iatrogenic injuries.

RESULTS

Three hundred cases of cholelithiasis comprising 255 (85%) females and 45 (15%) males with mean age of 39.85 +/- 18.82 years were included in the study. Patients mainly presented with upper abdominal pain including pain in right hypochondrium (71.67%), pain in right hypochondrium and epigastrium (19%) and pain in epigastrium alone (9.33%) as main symptoms. Operative findings revealed variations in 61 (20.33%) patients mainly involving cystic artery (10.67%), cystic duct (4.33%), right hepatic artery (2.67%) and gallbladder (2%). Postoperatively 3.67% revealed bleeding and 1.67% biliary leak from drain as main complications related to anatomical variations giving rise to 1% morbidity, however, no mortality was seen in this series.

CONCLUSION

Congenital anomalies and normal variants of biliary tree, are not common but may be of significance during laparoscopic surgery as failure to recognize them leads to iatrogenic injuries and can increase morbidity and mortality.

Intestinal metaplasia in gallbladder correlates with high amylase levels in bile in patients with a morphologically normal pancreaticobiliary duct

We reported previously that intestinal metaplasia in the gallbladder is strongly associated with expression of caudal-related homeobox transcription factor Cdx2. It has been documented that occult pancreatobiliary reflux, even in the absence of pancreaticobiliary maljunction, is associated with elevated risk of biliary malignancy. We ascertained the correlation between intestinal metaplasia in the gallbladder and occult pancreatobiliary reflux. In 196 patients with a normal pancreaticobiliary ductal arrangement who had undergone laparoscopic cholecystectomy, we performed intraoperative cholangiography and measured amylase levels in bile sampled from the gallbladder. The cutoff value for high cystic amylase was defined as a biliary amylase level higher than the normal upper limit of serum amylase (215 IU/L). We also retrospectively reviewed the cholecystectomized tissue specimens to investigate the presence of intestinal metaplasia and expression of Cdx2. Then, we explored the relationship between intestinal metaplasia in the gallbladder and occult choledocho-pancreatic reflux. Intestinal metaplasia was found in 16.8% (33/196) of the gallbladders. The prevalence of choledocho-pancreatic reflux revealed by intraoperative cholangiography was not significantly different between cases with intestinal metaplasia (5/33, 15.2%) and those without (25/163, 15.3%; P = .81). However, in cases with intestinal metaplasia, the rate of high cystic amylase (13/33, 39.4%) was significantly higher compared with cases without intestinal metaplasia (26/163, 16.0%, P = .005). In conclusion, intestinal metaplasia in the gallbladder is significantly correlated with high amylase levels in bile in patients with a morphologically normal pancreaticobiliary ductal arrangement.

Surgical anatomy of hepatic hilum with special reference of the plate system and extrahepatic duct

BACKGROUND

When resecting hilar cholangiocarcinoma, the surgeon cannot visualize the hilar vessels through thick connective tissue known as the plate system. Little has been reported regarding the anatomical relationship between the plate system and the extrahepatic bile duct.

METHODS

Twenty-five formalin-fixed cadaveric livers were dissected carefully and 7 were sectioned sagittally. The extent, composition, and distribution of the extrahepatic bile ducts within the system were investigated. The length between the confluence of the hepatic duct and the branch point of the segmental duct (level I) and the length between the branch point of the segmental duct and the segmental Glisson's pedicle (level II) were measured.

RESULTS

The plate system-composed of the hilar, cystic, Arantian, and umbilical regions--was easily separated from the hepatic parenchyma. Histologically, dense connective tissue with abundant capillaries, lymphatic vessels, and neural fibers were noted. Level I of B1pcp and B4a measured 13.0 and 14.7 mm, respectively. Level II measured 8.6 and 17.3 mm, respectively.

CONCLUSIONS

The bile ducts in the plate system correspond to the extrahepatic bile ducts and their lengths are variable for every segment. Knowing the lengths of the resectable extrahepatic bile ducts is useful for deciding which segment should be resected according to the cancerous invasion.

Preoperative evaluation of the extrahepatic bile duct structure for laparoscopic cholecystectomy

BACKGROUND

The incidence of aberrant bile duct injury associated with laparoscopic cholecystectomy (LC) has not yet been adequately examined. This study aimed to clarify the types of normal cystic ducts and the incidence of aberrant extrahepatic bile ducts, and to search for a method of avoiding injuries during LC.

METHODS

Aberrant hepatic ducts were retrospectively categorized into five types according to the pattern of the cystic ducts and the accessory hepatic ducts by preoperative endoscopic retrograde cholangiography or multidetector three-dimensional computed tomography using drip infusion cholangiography. The aberrant bile ducts were classified as type A (merging at the right side of the common bile duct), type B (merging at the anterior side), or type C (merging at the posterior left side).

RESULTS

The intrahepatic bile ducts and cystic duct were clearly shown for 1,044 of the 1,278 patients who underwent LC. Secondary branches of aberrant cystic ducts were observed in 37 cases (3.5%), and accessory hepatic ducts were observed in 30 cases (2.9%). A comparison of the difficulties encountered with LC for each type based on the merging patterns of cystic ducts showed that type C needed a much longer operation time for LC than the other types.

CONCLUSIONS

A preoperative evaluation of the bile duct tract and the accessory hepatic duct before LC is important. Patients with a cystic duct merging normally into the posterior left side of the common hepatic duct (type C) experienced difficulty when undergoing LC. The authors have safely performed LC with the use of an endoscopic nasobiliary drainage tube in type D cases (cystic duct merging with the right hepatic duct), in type IV cases (cystic duct merging with an accessory hepatic duct).

[The method of transillumination verification of extrahepatic biliary ducts and vessels during performance of laparoscopic and open cholecystectomy]

There was conducted analysis of the treatment results in 214 patients, operated on for cholelithiasis. In 106 of them (main group) transillumination verification of extrahepatic biliary ducts and vessels was applied and in 108 (control group) - the conventional methods were applied. The expediency of application of transillumination verification of extrahepatic hiliary ducts and vessels during performance of laparoscopic and open cholecystectomy was established. The method application had permitted to decrease trustfully the intraoperative complications frequency.

Innervation of the extrahepatic biliary tract

The extrahepatic biliary tract is innervated by dense networks of extrinsic and intrinsic nerves that regulates smooth muscle tone and epithelial cell function of extrahepatic biliary tree. Although these ganglia are derived from the same set of precursor neural crest cells that colonize the gut, they exhibit structural, neurochemical, and physiological characteristics that are distinct from the neurons of the enteric nervous system. Gallbladder neurons are relatively inexcitable, and their output is driven by vagal inputs and modulated by hormones, peptides released from sensory fibers, and inflammatory mediators. Gallbladder neurons are cholinergic and they can express a number of other neural active compounds, including substance P, galanin, nitric oxide, and vasoactive intestinal peptide. Sphincter of Oddi (SO) ganglia, which are connected to ganglia of the duodenum, appear to be comprised of distinct populations of excitatory and inhibitory neurons, based on their expression of choline acetyltransferase and substance P or nitric oxide synthase, respectively. While SO neurons likely receive vagal input and their activity is modulated by release of neuropeptides from sensory fibers, a significant source of excitatory synaptic input to these cells arise from the duodenum. This duodenum-SO circuit is likely to play an important role in the coordination of SO tone with gallbladder motility in the process of gallbladder emptying. Now that we have gained a relatively thorough understanding of the innervation of the biliary tree under healthy conditions, the way is paved for future studies of altered neural function in biliary disease.

Contribution of magnetic resonance cholangiography to the anatomic study of bile ducts

BACKGROUND/AIMS

Until recently, in-depth anatomic study of the biliopancreatic ducts was only possible with injection-corrosion techniques or peroperative radiology. These were tedious and tributary of the quality of anatomic specimens. Since 1990, a new minimally invasive technique has been available: nuclear magnetic resonance cholangiography (NMRCP). The aim of the study was to evaluate the feasibility and the results of NMRCP applied to the study of the biliopancreatic tract.

METHODOLOGY

NMRCP was performed in 50 healthy volunteers and results were interpreted by two readers in consensus.

RESULTS

NMRCP showed the common bile, left hepatic and paramedian ducts in 100% of cases. The right hepatic duct was seen in 78% of cases. The lateral duct was seen in 98% of cases. Segmental ducts were found in 68 to 78% of cases for segments II, III, VI, VII and VIII. Only 18% of ducts for segment I were found. The gallbladder was seen in only 72% of cases. The cystic duct was clearly seen in 64% of cases. The hepato-pancreatic duct was seen in 82% of cases. In 70% of cases, distribution of the hepatic ducts was modal. The remaining 30% displayed variations.

CONCLUSIONS

The anatomic and radiological results reported in our study of 50 cases demonstrate the excellent feasibility and reliability of magnetic resonance cholangiography applied to the anatomic study of the bile ducts. We suggest that a wide scale multicenter study in living healthy individuals may be worth considering.

Anatomic variations in right liver living donors

BACKGROUND

Anatomic knowledge is crucial in right liver living donor transplantation.

STUDY DESIGN

We reviewed radiologic and surgical findings in right liver donors. Arterial and portal anatomy was assessed in 96 donors, biliary anatomy in 77, and hepatic venous anatomy in 65.

RESULTS

Portal vein (PV): 86.4% had classic anatomy; 6.3% had a trifurcated PV; 7.3% had a right anterior PV taken off the left PV. Hepatic artery (HA): 70.8% had classic anatomy; 12.5% had a left HA arising from the left gastric artery; 13.5% had a right HA arising from the superior mesenteric artery; 2.1% had a double replaced left HA and right HA; and in 1.0% the common HA arose from the superior mesenteric artery. Biliary tree: 55.8% had normal anatomy; 14.3% had a trifurcated biliary anatomy; in 5.2% the right anterior bile duct and in 15.6% the right posterior bile duct opened into the left bile duct; in 2.6% the right anterior and in 6.5% the right posterior ducts opened into the common bile duct. Hepatic veins: S5 and S8 accessory hepatic veins had incidences of 43% and 49%, respectively. The incidence of S6 or S7 short hepatic vein was 38%.

CONCLUSIONS

Anatomic variations are common but do not contraindicate donation; surgeons should be prepared to recognize and manage them.

Variations of intrahepatic and proximal extrahepatic bile ducts

BACKGROUND/AIMS

The modern segmental concept of the liver with a segmental bile duct distribution is of practical importance for biliary specialists and should include information on variations of intrahepatic and extrahepatic bile ducts. The aim of this study was to find biliary variations, especially on a segmental and sectorial level, and to try to arrange them into types.

METHODOLOGY

We analyzed 51 corrosion casts of the human liver, which enabled the three-dimensional study of extrahepatic, sectorial, segmental and subsegmental bile ducts, their variations in course and confluencing, and the relationship between the structures of the portal pedicle.

RESULTS

The types of confluence and their frequency were determined separately for the left, right, right anterior sectorial, right posterior sectorial and common hepatic ducts. "Normal" left confluence was formed in 82% and three variations in 18%. "Normal" right confluence was formed in 75% and four variations in 25%. A complete ("normal") anterior sectorial duct was present in 35% and four variations in 65%. A complete ("normal") posterior sectorial duct was present in 61% and four variations in 39%.

CONCLUSIONS

The study showed that the biliary tree variations are quite frequent, and therefore clinically important, and that they could be arranged into several types.

A morphological and morphometric study of extra hepatic biliary duct of autopsied population of Bangladesh

The study was carried out in 20 humans to observe the mean length, external and luminal diameters of different parts of the extra-hepatic bile duct. The largest mean length and diameters were found in common bile duct.

Anatomical variations of gallbladder and biliary ducts among Ethiopians

The extrahepatic biliary system was investigated to determine the types and frequency of variations in a group of Ethiopian subjects. A total of 110 specimens were obtained from adult Ethiopian subjects. Each specimen consisting of the whole of the liver, stomach, duodenum and the lesser omentum was removed and dissected carefully to expose the gallbladder and biliary ducts without disturbing their relationship. The majority (51%) of subjects had supramarginal type of gallbladder. The neck and infundibulum of the gallbladder were shorter in the present group compared to reports in other populations. There were significantly more cases of kinking of the gallbladder and Hartmann's pouch in the female than in the male subjects. However, there was no significant difference between the present and previously reported groups as well as the male and female subjects of the present group in the length or course of the cystic, hepatic or bile ducts. The findings in the present study suggest that variations in the gallbladder and the biliary ducts seen in the Ethiopian group are similar to what is reported in other populations. The significantly higher prevalence of kinking of the gallbladder and Hartmann's pouch in the female than in the male subjects may have some contribution to the higher rate of gallstone formation and biliary tract diseases in females.

Extrahepatic bile duct length in the Singapore population

BACKGROUND

Although the length of the common bile duct is well documented, the length of extrahepatic biliary tree is less well studied, particularly in among the Asian population. The extrahepatic bile duct (BD) length is defined as the measurement from the hepatic hilum to the papilla.

OBJECTIVE

This study was performed to assess the normal range of extrahepatic BD length, as defined above, in the Singapore population. This information would be useful in assisting the local endoscopy unit in procuring the different lengths of biliary stents.

METHOD

Between 1.8.96 to 1.12.97, 486 cholangiograms were obtained post-ERCP, of which only 100 cholangiograms that were representative of a non-distorted BD were used for analysis. The BD length, taken from the mid-point of the confluence of the left and right hepatic ducts at the hilum to the papilla, was measured with a string placed on the cholangiogram. The true length was obtained after correction for radiological magnification.

RESULTS

The range of bile duct lengths followed a normal distribution curve with a mean length of 9.6 cm. The range was from 6.9 cm to 12.6 cm. With respect to the length of stents commonly deployed, the cumulative percentage of BD length less than and equal to 7-, 9-, 10- and 12-cm were 1%, 38%, 57% and 98% respectively.

CONCLUSION

From a practical point of view, this study suggests that endobiliary stent of 5 cm in length should be readily available for drainage of distal CBD strictures as 1% of our population has BD length less than 7 cm. However, as 2% of the population has BD length greater than 12 cm, 15 cm stents should be available in the endoscopy unit for drainage of hilar obstructions/strictures.

Anatomy of the porta hepatis as a basis for extended hepatoporto-enterostomy for extrahepatic biliary atresia--a new surgical technique

Reports on long-term survival rates after Kasai's HPE reveal that 23% of patients are healthy ten and more years after surgery. Therefore we studied again the anatomy and histology of the porta hepatis and the portal tracts in order to improve this surgical procedure.

METHODS

Autopsied livers of 6 children with and 6 without EHBA were investigated with regard to the topographical and histological anatomy of the major intra- and extrahepatic bile ducts.

RESULTS

On the basis of anatomical findings we have modified the conventional Kasai's HPE and developed an extended exploration of the porta hepatis. The procedure and surgical technique is described in this paper.

Smooth muscle distribution in the extrahepatic bile duct: histologic and immunohistochemical studies of 122 cases

The distribution of smooth muscle fibers in the extrahepatic bile duct (EBD) wall is not well characterized. We analyzed 101 consecutive Whipple's operation specimens and 21 autopsy specimens for the pattern of smooth muscle distribution in EBD using the Masson-trichrome stain and the desmin immunohistochemical stain. The patterns were categorized as continuous, interrupted, scattered, and no muscle layer. EBDs were divided into lower, middle, and upper portions, and the distribution pattern of smooth muscle fibers was analyzed separately in each portion. Because most surgically resected specimens contained the middle and lower EBDs with only a portion of the upper EBD, only the length of the middle and lower EBDs (common bile duct, CBD) was measured. The mean length of CBD in surgically resected specimens was 6.4 +/- 1.4 cm (men, 6.6 +/- 1.3 cm; women, 6.1 +/- 1.5 cm). The mean length of CBD in autopsy specimens was 6.8 +/- 1.0 cm. The predominant patterns of the lower third of the EBD were interrupted (49%) and continuous (43%). The predominant patterns of the middle third of the EBD were scattered (63%) and interrupted (23%). Those of the upper third of the EBD were no muscle fiber (58%) and scattered (39%). In conclusion, different patterns of smooth muscle distribution were observed in different portions of the EBD. Because scattered muscle fibers or no muscle fibers were the main features of the upper third of the EBD, understanding of this pattern may be helpful for assessment of the depth of invasion or staging of carcinoma of the upper third of the EBD.

Analysis of the arterial supply of the extrahepatic bile ducts and its clinical significance

The purpose of this study is to describe the arterial supply of the entire extrahepatic bile duct system. The cross-sectional area of all arteries that supply the ducts is measured under an operating microscope in 50 adult cadavers injected with red latex through the aorta. The extrahepatic bile duct system is divided into four topographic portions: cystic duct and gallbladder, right and left hepatic ducts, bile (common) duct and including its supra-retroduodenal parts, and the pancreatic and intraduodenal portions. The arterial supply to each portion is carefully detailed. The ducts are supplied by more than seven arteries, of which the major arteries are the cystic artery, posterior superior pancreaticoduodenal artery, right hepatic artery, and retroportal artery. Collectively they provide 94.5% of the blood supply to the ducts. Arteries form three types of anastomotic patterns on the walls of the ducts, suggesting that ductal incisions can be made in ways that least disturb the blood supply. The patterns are: a network, a longitudinal anastomotic chain, and an arterial circle. These data emphasize the importance of the arterial supply in biliary surgery and especially the treatment of hemobilia.

Stereomatic constants of the biliary tree in normal functional state and during experimental cholestasis

It has been found from the study of cholangiograms and laboratory specimens of biliary systems of human beings and dog's that the decrease in average diameters of biliary ducts during their passage from the hepatic portals to the periphery, is in accordance with the equation D = e-kz+b (z--sequence no of the duct, D--diameter of the duct, k--rate of change in the diameter, b--logarithm of diameter when z = 0). It has been established that parameter (b) defines size of the liver, and parameter (k) does not depend upon hepatic dimensions and changes during pathological processes. The use of (k) is recommended as an aid in defining the general character of dynamics of the duration of a given pathology.

A study on biliary ductal system and bile fistula in the American alligator, Alligator mississippiensis

The anomalous arrangement of bile ducts in the Crocodylia has not been fully appreciated. A clear understanding of biliary anatomy is necessary in order to create complete bile drainage in these reptiles. The object of this study was to clarify the anatomy of the bile ductal system and to establish total bile fistulas in the American alligator, Alligator mississippiensis. Bile duct anatomy was studied in 104 juvenile alligators, and bile fistulas were constructed in seven alligators. In 93 out of 104 (89%) of the juveniles dissected there was an interconnection between the right and left hepatic duct before the right hepatic duct emptied into the gallbladder. The left hepatic duct then entered the duodenum independently of the cystic duct which drained the gallbladder directly into the duodenum. In 8% of the animals, the left hepatic duct did not enter the duodenum but joined with the right duct, forming a common hepatic duct that emptied into the gallbladder. In 3% of the cases, the right hepatic duct emptied into the gallbladder, while the left duct had no communication with the right hepatic duct and drained separately into the duodenum. This arrangement of bile ducts is similar to that seen in birds and reflects the common ancestry of crocodiles and birds. In other reptiles, the biliary system shows much more variability and is different from the alligator. In five of seven alligators in which total biliary diversion was attempted, the biliary catheter remained in place and stayed patent from 2-7 weeks. Bile flow was extremely low (1.5-2.5 ml/24 h) when compared to that of mammals (80-100 ml/24 h). This study demonstrates the variable nature of the biliary ductal system in Alligator mississippiensis and suggest a method for constructing an effective total bile fistula in these animals.

Microstructure and development of the normal and pathologic biliary tract in humans, including blood supply

Microstructure and development of the normal biliary tract and the pathologies of several biliary tract diseases in humans are reviewed. The biliary tract, comprising the bile duct and peribiliary glands, is anatomically divided into the extrahepatic and intrahepatic biliary tree. The intrahepatic biliary tree is further divided into large bile ducts, corresponding to the right and left hepatic ducts and their first to third order branches, and into septal and interlobular bile ducts and bile ductules according to their size and location relative to the hepatic lobules and surrounding structures. The right and left hepatic ducts and the extrahepatic bile ducts are composed of dense fibrous duct walls lined by a layer of columnar biliary epithelium. The peribiliary glands, which may secrete mucinous and serous substances into the bile, are found along the extrahepatic and large intrahepatic bile ducts. They are divided in glands within and outside the duct wall. The former (intramural glands) drain directly into the lumen of the bile duct, while the latter (extramural glands) are composed of several lobules and drain into the ductal lumen via their own conduits. The biliary tract is supplied by a complex vasculature called the peribiliary vascular plexus. Afferent vessels of this plexus derive from hepatic arterial branches, and this plexus drains into the portal venous system or directly hepatic sinusoids. The development of the intrahepatic biliary tract is divided into three stages: the stage of the ductal plate, the stage of biliary cell migration into the mesenchyme, and the stage of bile duct formation in the portal tract. It remains unclear how the extrahepatic and intrahepatic biliary tract integrate. Along with these developmental changes in the biliary tract, the peribiliary glands and the vascular plexus also develop in a step-wise manner and their maturation is completed after birth. Pathologies of various biliary diseases are briefly reviewed noting their relevance to several histologic elements and the microenvironment of the biliary tract and the developmental anomalies of the biliary tract including ductal plate malformation.

[Main variations of the extrahepatic biliary system and their application to the so-called "split-liver" transplantation technique]

Sixty fresh adult livers were obtained from cadavers together with celiac trunk, head of the pancreas and superior mesenteric artery. We have found a single right hepatic duct in 13(21.6%) of the cases and a multiple right hepatic duct in 47(78.3%). A single left hepatic duct was found in 3(5%) of the cases and a multiple left hepatic duct in 57(95%). A median hepatic duct was found in 18(30%) of the cases, out of this 2(3.3%) was multiple median hepatic duct.

Healing process of sutureless choledochojejunostomy in an experimental model

The healing characteristics and morphological features of sutureless choledochojejunostomy were investigated in a rat experimental model. The common bile duct of 34 conditioned Wistar rats was exposed, divided transversely and a choledochojejunostomy constructed with only a vinyl chloride tube positioned between the common duct and jejunum. The animals were killed 4, 12 and 52 weeks after surgery. Cholangiographic evaluation of the anastomosis in all three groups showed wide openings with dilatation of the extrahepatic bile duct. Microscopic examination of the anastomosis showed hyperplastic changes of the bile duct epithelium. The epithelial defect was completely covered with proliferative epithelium 12 weeks after operation. At long-term follow-up of 52 weeks there were no biliary strictures after the sutureless technique. This surgical approach may be useful for patients in whom sutured anastomosis of the bile duct might lead to stricture, such as those with a normal thin-walled bile duct.

[Variations in extrahepatic bile ducts, their arteries and pancreatic ducts]

The author presents a brief account of congenital varieties of extrahepatic biliary pathways, a cystica and pancreatic ducts and explains their development. Good knowledge of these varieties is of great importance for detailed preparation in laparoscopic cholecystectomy and during fibroscopic examination of duodenal papillae.

Structure and innervation of the extrahepatic biliary system in the Australian possum, Trichosurus vulpecula

The morphology, microanatomy and innervation of the biliary tree of the Australian possum, Trichosurus vulpecula, was examined. The gross morphology of the gallbladder, hepatic and cystic ducts, and the course of the common bile duct, conforms to those of other species. The sphincter of Oddi has an extraduodenal segment that extends 15mm from the duodenal wall; within this segment the pancreatic and common bile ducts are ensheathed together by sphincter muscle. Their lumens unite to form a common channel within the terminal intraduodenal segment. Nerve cell bodies of the gallbladder were found in an inter-connecting network of ganglia that were located in the serosa, muscularis and mucosa. Nerve fibres innervated the muscle, arterioles and the mucosa. Few ganglia were found along the supra sphincteric portion of the common bile duct. Nerve trunks followed the duct and a dense nerve fibre plexus was found in the mucosa. In the sphincter most ganglia were located in two plexuses, the first between the layers of the external sphincter muscle, which was continuous with the external muscle of the duodenum, and the second was associated with the internal sphincter muscle. Nerve fibres were numerous in the sphincter muscle, and were also found in the subepithelial and periglandular plexuses of both the pancreatic and common bile ducts.

Biomechanical study of the bile duct system outside the liver

Diseases of the bile duct system in the digestive system after surgery are common. In order to clarify the cause of these diseases, research on the diseases from a biomechanical perspective is increasing; however, the same cannot be said of biochemical research. In this paper, by using a new, well-devised testing apparatus, specimens extracted from the bile duct system of canine body are tested. The test data are analyzed using the finite deformation theory, and mechanical properties of the bile duct system outside the liver are investigated. The conclusions show that the viscoelasticity of the bile duct system is very small. In its normal physiological condition, the bile duct wall has an almost uniform distribution of circumferential and longitudinal stress. However, when the diseases of the bile duct system cause high pressure at the bile duct, the circumferential stress and longitudinal stress at the bile inside wall suddenly increase and are much larger than those stresses at the outside wall. The elastic modulus gradually becomes small from the common bile duct and the common hepatic duct to hepatic duct, and the value of elastic modulus for the cystic duct is almost equal to that of the hepatic duct.