Morphometric study of extra-hepatic biliary pathways: study in human corpses / Estudio morfométrico de las vías biliares extrahepáticas: estudio en cadáveres humanos

SUMMARY: Adverse events (AE) contribute significantly to postoperative morbidities and comorbidities. Many AEs occur due to a lack of anatomical knowledge and its variants. Latrogenic bile duct injuries, for instance, represent a serious surgical complication of laparoscopic cholecystectomy. Anatomical knowledge for the identification and adequate drainage of all ducts is relevant and fundamental in order to avoid future errors. The objective of the study was to morphometrically analyze the bile ducts in adult human corpses. 13 livers were extracted from adult human corpses to obtain the ducts: choledochal, common hepatic and cystic. After morphological analysis, duct measurements (length and diameter) were continued using a digital caliper. The data obtained were tabulated in SPSS 21 program, performing descriptive analysis with mean and standard deviation. The averages of bile ducts were 61.05 (± 16.43) mm in length and 3.86 (± 0.72) mm in diameter. The cystic duct length and diameter averages were 33.59 (± 12.29) mm and 3.40 (± 0.79) mm, respectively. The common hepatic ducts had an average of 30.02 (± 7.19) mm in length and 3.74 (± 1.18) mm in diameter. The analyzed samples presented different values ?? from those already described in the literature, where the length of the cystic ducts was greater, while the length of the common hepatic ducts was numerically smaller. This work is very significant, as the morphometric variability of the bile ducts allows for varying morphological situations that can compromise the hepatobiliar physiology.

RESUMEN: Los eventos adversos (EA) contribuyen significativamente a las morbilidades y comorbilidades postoperatorias. Muchos EA se deben a la falta de conocimiento de la anatomía y sus variaciones. Por ejemplo, las lesiones iatrogénicas de las vías biliares representan una complicación quirúrgica grave de la colecistectomía laparoscópica. El conocimiento anatómico para la identificación y drenaje adecuado de todos los conductos es relevante y fundamental para evitar futuros errores. El objetivo del estudio fue analizar morfométricamente las vías biliares en cadáveres humanos adultos. Se extrajeron 13 hígados de cadáveres humanos adultos y se retiraron los conductos: colédoco, hepático común y cístico. Después del análisis morfológico, se continuó con las mediciones de los conductos (longitud y diámetro) utilizando un calibrador digital. Los datos fueron tabulados en el programa SPSS 21, mediante análisis descriptivos con media y desviación estándar. Los promedios de las vías biliares fueron de 61,05 (± 16,43) mm de longitud y 3,86 (± 0,72) mm de diámetro. Los promedios de longitud y diámetro del conducto cístico fueron 33,59 (± 12,29) mm y 3,40 (± 0,79) mm, respectivamente. Los conductos hepáticos comunes tenían un promedio de 30,02 (± 7,19) mm de longitud y 3,74 (± 1,18) mm de diámetro. Las muestras analizadas presentaron valores diferentes a los ya descritos en la literatura, donde la longitud de los conductos císticos era mayor, mientras que la longitud de los conductos hepáticos comunes fue numéricamente menor. Este trabajo es significativo, debido a que la variabilidad morfométrica de las vías biliares y permite identificar situaciones morfológicas que pueden comprometer la fisiología hapatobiliar.

Unusual anatomical variations of the hepatic arteries and bile ducts: What are the surgical implications.

Introduction: The knowledge of anatomy is essential for surgical safety and impacts positively on patients' outcomes. Surgeons operating on the liver and bile ducts should keep in mind the normal anatomy and its variations as the latter are common. Case Presentation: We conducted a structured surgical dissection course of the supra-colic compartment of the abdominal cavity on 2nd and 3rd October 2020. While dissecting a 46years-old male cadaver, we encountered unusual anatomical variations of the hepatic arterial branching, the biliary tree, and arterial supply to the common bile duct. The common hepatic artery was dividing into two branches: a common short trunk for the left hepatic artery and the right gastric artery (hepato-gastric trunk) and a common trunk for the right hepatic artery and gastroduodenal artery (hepato-gastroduodenal trunk). The right hepatic duct was duplicated with a main right hepatic duct and an additional smaller duct. The bile duct was supplied by an artery coming from the abdominal aorta. Conclusion: We described three unusual anatomical variations: a variation of the hepatic arteries branching pattern, an aberrant right hepatic duct, and blood supply to the bile duct from the abdominal aorta. Surgeons should be aware of these rare variations.

Bile duct anatomical variations: Relevance for liver division and preparing left split liver grafts for pediatric transplantation: Cohort study.

BACKGROUND: liver lateral section graft is the most common graft type used for transplantation in children worldwide. Compared to whole liver grafts, a higher rate of biliary complications has been described. Historically, 2 techniques have been described for transection of liver - trans-hilar or trans-umbilical parenchymal transection. Though these techniques allow dividing the biliary system at two distinct positions, the usual surgical strategies do not take advantage of this advantage. MATERIAL AND METHODS: A retrospective study was conducted on 40 candidates who volunteered for donation of their left lateral liver section for transplantation, between October 2017 and April 2019. Preoperative imaging was analyzed to depict the arterial and biliary anatomy of the liver and their variations, with a dedicated attention to the left liver (segments 2, 3 and 4). Anatomy of the biliary system was taken into account for defining the optimal surgical strategy - either through a trans-hilar or a trans-umbilical parenchymal transection. RESULTS: In 26/40 patients, arterial or biliary variations were much relevant for decision-making on the optimal plane of liver division (trans-umbilical (N = 14) and trans-hilar (N = 26)). This resulted in 23 grafts with a single artery and bile duct, 6 grafts with double arteries and a single bile duct, and 9 grafts with double bile ducts and a single artery; only two grafts had complex anatomy. There was no arterial complication and the overall incidence of biliary problems was 14.7%. All grafts are functioning well at a mean follow-up of 19.6 ± 8.5 months. CONCLUSIONS: Anatomical variations are frequent and their knowledge is relevant for procurement of lateral section liver graft. Knowledge of these variation, or -better- preoperative biliary imaging is helpful in guiding parenchymal transection at procurement and preparing optimal liver grafts.

Is an optical illusion the cause of classical bile duct injuries?

We sought to determine if lateral-inferior traction on the Hartmann pouch could produce bile duct kinking and subsequent misinterpretation of the space on the left side of the bile duct as the hepatobiliary triangle. Once traction was applied, we measured the angle between the cystic duct and inferior gallbladder wall hepatobiliary triangle) in 76 cases, and the angle between the common bile duct and common hepatic duct (porta hepatis "triangle") in 41 cases. The mean angles were significantly different (hepatobiliary triangle mean 68.2°, standard deviation [SD] 16.0°, range 23-109°; porta hepatis "triangle" mean 112.0°, SD 18.4°, range 72-170°; p < 0.01). The ranges, however, overlapped in 26 cases. In many cases, lateral-inferior traction on the Hartmann pouch produced substantial kinking of the bile duct that could easily elicit the illusion that it is the hepatobiliary triangle rather than the centre of the porta hepatis.

Importance of Imaging Plane of Gadoxetic Acid--Enhanced Magnetic Resonance Cholangiography for Bile Duct Anatomy in Healthy Liver Donors.

PURPOSE: The purpose of this study was to compare the image quality and accuracy of axial vs coronal contrast-enhanced magnetic resonance cholangiography (CE-MRC) for assessing bile duct anatomy. METHODS: Data from 313 healthy donors who underwent axial and coronal CE-MRC before liver donation were retrospectively analyzed. Motion artifacts and bile duct visibility were assessed using 4-point scales, with scores ≥3 considered interpretable. The sensitivity and specificity of axial and coronal CE-MRC for diagnosing anatomic variations were compared, as were the proportions of correctly categorized biliary anatomic types. RESULTS: Axial CE-MRC provided better image quality than coronal CE-MRC in terms of both motion artifacts (3.83 vs 3.17; P < .001) and duct visibility (3.50 vs 3.17, P < .001), resulting in more interpretable images with axial than coronal CE-MRC (92.7% vs 82.1%; P < .001). Among 249 donors with interpretable images, coronal CE-MRC performed significantly better for identifying duct anatomic variation than axial CE-MRC (sensitivity, 96.9% vs 80.4%, P < .001; specificity, 100% vs 96.7%, P = .025). Coronal CE-MRC was significantly better than axial CE-MRC at correctly categorizing anatomic types of right posterior hepatic duct into left hepatic duct and accessory duct with incomplete right hepatic duct. CONCLUSIONS: With interpretable image quality, coronal CE-MRC performed better than axial CE-MRC for evaluating bile duct anatomy.

Biliary reconstruction and complications in living donor liver transplantation.

For a technically successful liver transplant (LT), secure bile duct anastomosis to prevent biliary complications (BC's) like biliary anastomotic stricture (BAS) and bile leak (BL) is mandatory. BC's after living donor liver transplantation (LDLT) are relatively more common compared to deceased donor LT (DDLT), particularly owing to surgical factors (small diameter, and/or multiple bile duct openings on the graft), and non-surgical factors (immunologic reactions). Adequate blood supply to the bile duct both in donor and recipient, meticulous anastomotic technique, mucosal eversion for better approximation thus avoiding lesser fibrosis, proper use of internal or external stent drainage, and tension-free anastomosis, may contribute to the decrease of BC's after LDLT. Further, if BC's are not dealt with in a timely manner, these could progressively lead to severe morbidities and even mortality. While the endoscopic approach is preferred initially to deal with biliary leaks or strictures, the more invasive percutaneous approach may be required in case of endoscopic failure. Dedicated and experienced endoscopists, and interventional radiologists are key members of the multidisciplinary team in a successful LDLT program. In this review, we have tried to summarize current concepts in surgical techniques of biliary reconstruction in LDLT, incidence and risk factors for BC's, and principles followed to try and reduce the incidence of the same.

The role of living donor liver transplantation for acute liver failure.

Acute liver failure (ALF) is a life-threatening illness that occurs in the absence of pre-existing liver disease. When symptoms seriously progress under continuous supportive medical care, liver transplantation becomes the only therapeutic strategy. However, the available sources of organs for liver transplantation differ worldwide. In regions in which organs from cadaveric donors are more common, deceased donor liver transplantation (DDLT) is performed in this urgent situation. Conversely, in countries where cadaveric donors are scarce, living donor liver transplantation (LDLT) is the only choice. Special considerations must be made for urgent LDLT for ALF, including the expedited evaluation of living donors, technical issues, and the limitations of ABO blood type combinations between recipients and donor candidates. In this review, we highlight the role of LDLT for ALF and the considerations that distinguish it from DDLT. LDLT is well-established as a life-saving procedure for ALF patients and there is often no alternative to LDLT, especially in countries where DDLT is not feasible. However, from a global perspective, an increase in the deceased donor pool might be an urgent and important necessity.

Assessment of biliary anatomy in potential living liver donors: Added value of gadoxetic acid-enhanced T1 MR Cholangiography (MRC) including utilization of controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique in comparison to T2W-MRC.

OBJECTIVES: To assess the added value of gadoxetic-acid-enhanced T1-weighted magnetic resonance Cholangiography (T1W-MRC) including controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA)-Volumetric Interpolated Breathhold (VIBE) technique compared to T2-weighted MR Cholangiography (T2W-MRC) in depicting biliary anatomy in potential living liver donors. METHODS: Eighty-five potential donors including 34 men with a mean age of 35.6 years (range, 18-55 years) and 51 women with a mean age of 36.7 years (range, 23-57 years), were enrolled in this ethics-approved retrospective study. Image quality for depiction of bile ducts was evaluated by two readers in consensus in 3 separate reading sessions: 1) T2W-MRC alone, 2) T1W-MRC alone (including CAIPI-VIBE and generalized autocalibrating partially parallel acquisitions (GRAPPA)-VIBE techniques, and 3) combined T1W/T2W-MRC. Accuracy of T2W-MRC, T1W-MRC, and combined T1W/T2W-MRC for the identification/classification of the biliary variants was calculated using intraoperative cholangiogram (IOC) as the reference standard. Image quality and reader diagnostic confidence provided by CAIPI-VIBE technique was compared with GRAPPA-VIBE technique. Datasets were compared using the Wilcoxon signed-rank test. RESULTS: Image quality for depiction of the bile ducts was significantly superior in the combined T1W/T2W-MRC group, when compared to each of T2W-MRC and T1W-MRC groups independently (P value = 0.001-0.034). The combination of CAIPI-VIBE and GRAPPA-VIBE was superior compared to each of the sequences individually. The accuracy of T2W-MRC and T1W-MRC was 93% and 91%, respectively. T1W-MRC depicted four biliary variants better than T2W-MRC. Two variants not well seen in T2W-MRC were clearly shown on T1W-MRC. CONCLUSION: Gadoxetic-acid-enhanced T1W-MRC and conventional T2W-MRC techniques are complementary for depiction of biliary variants in potential liver donors and the combination of the two improves the results. The combination of CAIPI-VIBE and GRAPPA-VIBE techniques appear to be complementary for optimal diagnostic yield of T1W-MRC.

Influence of Bile Duct Diameter on Biliary Complications After Liver Transplantation.

Biliary complications after liver transplantation have a high incidence of and a significant impact on morbidity and mortality. The primary aim of this study was to assess the influence of bile duct diameter on biliary complications and to determine whether a critical diameter for such complications could be determined. The secondary aim was to identify additional factors associated with biliary complications. Two hundred and seventy-three recipients of liver transplantation with biliary anastomosis without a T-tube were analyzed from December 2013 to December 2018. Patients with a follow-up of less than 6 months were excluded, except for those with biliary complications (including death). Intraoperative measurements of bile duct diameter and other variables potentially related to complications were recorded prospectively, and their association with biliary complications was analyzed. Our results show that neither donor nor recipient bile duct diameters were risk factors for the development of biliary complications. However, bile duct size mismatch between recipient and donor was found to be a risk factor. Additional associated risk factors were arterial ischemia time, arterial complications, bench arterial reconstruction, and intraoperative blood transfusion.

A workflow for automated segmentation of the liver surface, hepatic vasculature and biliary tree anatomy from multiphase MR images.

Accurate assessment of 3D models of patient-specific anatomy of the liver, including underlying hepatic and biliary tree, is critical for preparation and safe execution of complex liver resections, especially due to high variability of biliary and hepatic artery anatomies. Dynamic MRI with hepatospecific contrast agents is currently the only type of diagnostic imaging that provides all anatomical information required for generation of such a model, yet there is no information in the literature on how the complete 3D model can be generated automatically. In this work, a new automated segmentation workflow for extraction of patient-specific 3D model of the liver, hepatovascular and biliary anatomy from a single multiphase MRI acquisition is developed and quantitatively evaluated. The workflow incorporates course 4D k-means clustering estimation and geodesic active contour refinement of the liver boundary, based on organ's characteristic uptake of gadolinium contrast agents overtime. Subsequently, hepatic vasculature and biliary ducts segmentations are performed using multiscale vesselness filters. The algorithm was evaluated using 15 test datasets of patients with liver malignancies of various histopathological types. It showed good correlation with expert manual segmentation, resulting in an average of 1.76 ± 2.44 mm Hausdorff distance for the liver boundary, and 0.58 ± 0.72 and 1.16 ± 1.98 mm between centrelines of biliary ducts and liver veins, respectively. A workflow for automatic segmentation of the liver, hepatic vasculature and biliary anatomy from a single diagnostic MRI acquisition was developed. This enables automated extraction of 3D models of patient-specific liver anatomy, and may facilitating better perception of organ's anatomy during preparation and execution of liver surgeries. Additionally, it may help to reduce the incidence of intraoperative biliary duct damage due to an unanticipated variation in the anatomy.

Anatomical variations and clinical relevance of cystic artery: a brief review

Although the cystic artery commonly originates from a right hepatic artery, variations in the origin and course of the cystic artery occur in 24.5% of people. The explanation for the variations of the cystic artery is found in the developmental pattern of the biliary system. Thus, the various origins of the cystic artery and its course concerning the Calot's triangle require the attention of surgeons in order to avoid iatrogenic injury of the bile ducts and vessels. Hence, the course of the cystic artery regarding hepatobiliary ducts has also to be noted by surgeons during cholecystectomy

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Biliary Leakage After Hepatobiliary and Pancreatic Surgery: A Classification System to Guide the Proper Percutaneous Treatment.

PURPOSE: To investigate the effectiveness of percutaneous approaches to treat bile leak and to propose an anatomical classification of biliary fistula to guide the most appropriate percutaneous approach. MATERIALS AND METHODS: Fifty-six patients with bile leakage after hepatobiliary surgery were included. Based on preoperative images and postoperative fistulogram images, three categories of bile leakage were defined. Every category was treated with non-surgical approaches (internal-external percutaneous drainage, percutaneous/endoscopic biliodigestive anastomosis with rendez-vous technique and biliodigestive percutaneous anastomosis with totally radiologic rendez-vous). RESULTS: In 44/56 (78%) patients, anatomical conformation was "direct communication" (bile ducts upstream from the leak present a direct communication with downstream ducts) and their treatment was conventional percutaneous drainage. In 5/56 (9%), anatomical conformation was "indirect communication" (bile ducts upstream from the leak communicate with downstream ducts through a bile collection) and treatment was percutaneous/endoscopic rendez-vous technique. In 7/56 (12%), anatomical conformation was "no communication" (ducts upstream from the leak are completely excluded from ducts downstream) and treatment was totally radiologic rendez-vous. In 54/56 (96%) during the follow-up, cholangiography revealed complete resolution of the leak without residual stenosis and drains were removed. Complications occurred in 12/56 (21%). Procedure-related mortality was 0%. Ten patients, after > 6 months from resolution of their fistula and drain removal, died due to cancer recurrence. Currently, 44/56 patients (77%) at long-term follow-up (> 12 months) are alive, without bile leak. CONCLUSION: Our classification helps to choose the most proper percutaneous approach in all kinds of bile leakage, even in severe cases; these are safe techniques with a high success rate.

Determining Bile Duct Density in the Mouse Liver.

Mouse is broadly used as a model organism to study biliary diseases. To evaluate the development and function of the biliary system, various techniques are used, including serum chemistry, histological analysis, and immunostaining for specific markers. Although these techniques can provide important information about the biliary system, they often do not present a full picture of bile duct (BD) developmental defects across the whole liver. This is in part due to the robust ability of the mouse liver to drain the bile even in animals with significant impairment in biliary development. Here we present a simple method to calculate the average number of BDs associated with each portal vein (PV) in sections covering all lobes of mutant/transgenic mice. In this method, livers are mounted and sectioned in a stereotypic manner to facilitate comparison among various genotypes and experimental conditions. BDs are identified via light microscopy of cytokeratin-stained cholangiocytes, and then counted and divided by the total number of PVs present in liver section. As an example, we show how this method can clearly distinguish between wild-type mice and a mouse model of Alagille syndrome. The method presented here cannot substitute for techniques that visualize the three-dimensional structure of the biliary tree. However, it offers an easy and direct way to quantitatively assess BD development and the degree of ductular reaction formation in mice.

Surgical and histological boundary of the hepatic hilar plate system: basic study relevant to surgery for hilar cholangiocarcinoma regarding the "true" proximal ductal margin.

BACKGROUND: We sought to expand the clinico-anatomical limit of the proximal ductal margin (Limit-PDM) for resectability of hilar cholangiocarcinoma (HCCA). METHODS: The practical boundary of the hilar plate (PBHP) was defined as the location where the bile duct (BD) could not be isolated by dissection. The distance between PBHP and two well-known clinical landmarks of Limit-PDM, the right edge of the bifurcation of the anterior and posterior branch of the right portal vein (Posterior-Landmark) and the left edge of the umbilical portion of the portal vein (Left-Landmark), and histological features around the PBHP were assessed using 55 adult cadaver livers. RESULTS: BD was almost always isolatable beyond the traditional clinical landmarks. The median distance was 6.9 mm (interquartile range [IQR] 6.0-8.3 mm) between the PBHP and the Posterior-Landmark, and 8.9 mm (IQR 6.7-10.2 mm) between the PBHP and the Left-Landmark. Histologically, the sheath surrounding the portal triad was loose, thick with few elastic fibers and small arteries near the hepatic hilum. Near the PBHP, the sheath was dense, thin, and abundant with elastic fibers and small arteries. CONCLUSIONS: Limit-PDM is more peripheral than the traditional clinical landmark-based margin and histological transition near the PBHP was revealed.

A New Approach to Accomplish Intraoperative Cholangiography in Left Lateral Segmentectomy of Living Liver Donation.

BACKGROUND There are 2 main methods of bile duct division in harvesting left lateral segment of a living donor: 1) by intraoperative cholangiography through cystic duct with cholecystectomy, or 2) by direct vision with preoperative magnetic resonance cholangiopancreatography. Here, we present a new approach to cholangiography by using the bile duct stump of the fourth liver segment (B4 stump) to achieve left lateral segmentectomy in pediatric living donor liver transplantation. MATERIAL AND METHODS This was a prospective study of 221 living donors who had undergone intraoperative cholangiography via the B4 stump in the course of left lateral segmentectomy. We collected and analyzed the clinical data, including the success rate of cholangiography by catheterizing the B4 stump; the associated time cost; the classification of the donor liver's biliary anatomy; the number of bile duct orifices on the graft side; and postoperative complications involving the biliary tract. RESULTS We were successful in catheterizing B4 stumps in all 221 patients. The mean time cost of these procedures was 7.21±3.62 minutes. Variations in the confluence of the right and left lobes were found in 58 patients (26.24%). Overall, sludge was detected in 18 cases (8.14%), gallstones were found in 3 patients (1.36%), and a polypoid gallbladder lesion was found in 1 patient (0.45%). There were 11 cases (4.98%) of bile leakage; no biliary strictures were found in the donors. CONCLUSIONS Intraoperative cholangiography via the B4 stump is an alternative procedure for living donors who undergoes left lateral segmentectomy.

Evaluation of biliary anatomy in the caudate lobe using drip infusion cholangiography-computed tomography.

PURPOSE: This study aimed to retrospectively evaluate the caudate branches (CBs), which are bile ducts originating from the caudate lobe (CL), using drip infusion cholangiography with computed tomography (DIC-CT). METHODS: The confluence patterns of CBs were evaluated in 185 adult patients undergoing DIC-CT. The following bile duct features were evaluated: (a) number of depicted CBs; (b) identification of the caudate portion from which the CBs were derived; (c) identification of the confluence site of a CB; and (d) whether there was a difference in the confluence site of the CBs depending on the position of the right posterior hepatic duct (RPHD) and the portal vein (PV). RESULTS: DIC-CT enabled detection of a total of 640 bile ducts from the CL in 185 patients, and the total number of CBs from the Spiegel lobe (SP), the paracaval portion, and the caudate process (CP) were 347 (54.2%), 112 (17.5%), and 181 (28.2%), respectively. In the SP, over 60% of CBs joined the left hepatic duct system (LHDS). The positional relationship between the RPHD and the PV was divided into a supra-portal course (n = 168) and an infra-portal course (n = 17). The number of CBs joining the LHDS was significantly different between a supra-portal course and an infra-portal course (p = 0.0484). CONCLUSION: CBs were depicted by DIC-CT in 98.9% of the subjects, and a detailed evaluation was possible. The number of CBs joining the LHDS was associated with the position of the RPHD and the PV.