Does portal vein anatomy influence intrahepatic distribution of metastases from colorectal cancer?

BACKGROUND: Other than location of the primary colorectal cancer (CRC), a few factors are known to influence the intrahepatic distribution of colorectal cancer liver metastases (CRLM). We aimed to assess whether the anatomy of the portal vein (PV) could influence the intrahepatic distribution of CRLM. PATIENTS AND METHODS: Patients with CRLM diagnosed between January 2018 and December 2022 at two tertiary centers were included and imaging was reviewed by two radiologists independently. Intra-operator concordance was assessed according to the intraclass correlation coefficient (ICC). The influence of the diameter, angulation of the PV branches and their variations on the number and distribution of CRLM were compared using Mann-Whitney, Kruskal-Wallis, Pearson's Chi-square and Spearman's correlation tests. RESULTS: Two hundred patients were included. ICC was high (> 0.90, P < 0.001). Intrahepatic CRLM distribution was right-liver, left-liver unilateral and bilateral in 66 (33%), 24 (12%) and 110 patients (55%), respectively. Median number of CRLM was 3 (1-7). Type 1, 2 and 3 portal vein variations were observed in 156 (78%), 19 (9.5%) and 25 (12%) patients, respectively. CRLM unilateral or bilateral distribution was not influenced by PV anatomical variations (P = 0.13), diameter of the right (P = 0.90) or left (P = 0.50) PV branches, angulation of the right (P = 0.20) or left (P = 0.80) PV branches and was independent from primary tumor localisation (P = 0.60). No correlations were found between CRLM number and diameter (R: 0.093, P = 0.10) or angulation of the PV branches (R: 0.012, P = 0.83). CONCLUSIONS: PV anatomy does not seem to influence the distribution and number of CRLM.

Classification of variant portal vein anatomy based on three-dimensional CT: surgical implications.

PURPOSES: The purpose of this study was to develop a new and more comprehensive classification system for portal vein (PV) variations using three-dimensional visualization and evaluation (3DVE) and to discuss the prevalence rates and clinical implications of the variants. METHODS: The anatomies of PVs were tracked and analyzed by using three-dimensional visualization of CT images acquired between 2013 and 2022. Scans from 200 adults were evaluated and a total of 178 patients (N = 178) were included in the study. The new classification system, named BLB classification, was developed based on the level of the absent PV branch in each variant anatomy. RESULTS: Using the BLB classification system, PVs were divided into thirteen subtypes. Only 82.6-84.8% of the portal veins of the 178 patients were depicted in Atri's, Cheng's or Covey's classification, compared with 100% identified by the BLB classification. The BLB classification was validated against external data sets from previous studies, with 97.0-98.9% of patients classified by the BLB system. CONCLUSION: Variant PV anatomies are more commonly seen based on 3DVE than in previous reports. The BLB classification covers almost all portal vein variants and may be used for planning liver surgery.

Evaluation of ventral branches of segment VI portal vein relative to the right hepatic vein in laparoscopic right anterior sectionectomy.

INTRODUCTION: The right intersectional plane and the right hepatic hilum were noted too often exhibit anatomical variations, making difficult the laparoscopic right anterior sectionectomy (LRAS). METHODS: We analyzed the anatomical features employing 3D-CT images of 55 patients, and evaluated these features according to the course of ventral branches of segment VI of the portal vein (PV, P6a) relative to the right hepatic vein (RHV). RESULTS: P6a run on the dorsal side of RHV in 32 patients (58%, Dorsal-P6a) and the ventral side of RHV in 23 (42%, Ventral-P6a). Ventral-P6a had more patients with S6 partially drained by middle hepatic vein (MHV, 39% vs. 0%, P < 0001), the narrower angle between the anterior and posterior branches of PV (73.1° vs. 93.8°, P = 0.006), the wider angle between the RHV and inferior vena cava  (54.3° vs. 44.3°, P < 0.001), and more steeply pitched angle between S6 and S7 along the RHV (140.6° vs. 162.0°, P < 0.001) compared to Dorsal-P6a. CONCLUSION: In LRAS for Dorsal-P6a patients, the transection surface was relatively flat. In LRAS for Ventral-P6a patients, the narrow space between anterior and posterior glissons makes difficult the glissonean approach. The transection plane was steeply pitched, and RHV was partially exposed. S6 was often partially drained to MHV in 39% of the Ventral-P6a patients, which triggers congestion during liver transection of a right intersectional plane after first splitting the confluence of this branch.

Sonographic and Anatomical Evaluation of the Liver and Portal Vein Reference Values / Evaluación Ecográfica y Anatómica de los Valores de Referencia del Hígado y la Vena Porta

SUMMARY: This paper's aim is a morphometric evaluation of liver and portal vein morphometry using ultrasonography in healthy Turkish population. This study was carried out with 189 subjects (107 females, 82 males). The demographic data and the body surface area were calculated. The longitudinal axis of the liver for two lobes, diagonal axis or liver span, anteroposterior diameter of the liver and portal vein, portal vein transverse diameter, caudate lobe anteroposterior diameter, and portal vein internal diameters as well as longitudinal liver scans in an aortic plane, sagittal plane, transverse plane, and kidney axis were measured. All measurements were analyzed according to age, sex, body mass index, obesity and alcohol consumption. The mean values of the age, height, weight and body mass index were calculated as 44.39 years, 167.05 cm, 74.23 kg, and 27.06kg/m2 in females, respectively. The same values were 44.13 years, 167.70 cm, 75.93 kg and 26.71 kg/m2 in males, respectively. There was significant difference between demographic characteristics, gender, and alcohol consumption in terms of anteroposterior diameter of the liver, portal vein transverse diameter of the right side and liver transverse scan. Also, some measurements including portal vein transverse diameter, liver transverse scan and at kidney axis longitudinal scan of liver showed significant difference between the age groups. There was significant difference in diagonal axis and anteroposterior diameter of liver, portal vein internal diameter, and longitudinal liver scans of the aortic plane parameters between obesity situation. The findings obtained will provide important and useful reference values as it may determine some abnormalities related liver diseases. Also, age, sex, obesity and body mass index values can be effective in the liver and portal vein morphometry related parameters.

El objetivo de este artículo fue realizar una evaluación de la morfometría del hígado y la vena porta mediante ecografía en una población turca sana. Este estudio se llevó a cabo en 189 sujetos (107 mujeres, 82 hombres). Se calcularon los datos demográficos y la superficie corporal. Se midió eleje longitudinal del de dos lóbulos del hígado, el eje diagonal o la extensión del hígado, los diámetros anteroposterior del hígado y de la vena porta, el diámetro transversal de la vena porta, anteroposterior del lóbulo caudado y los diámetros internos de la vena porta, así como las exploraciones longitudinales del hígado en un plano aórtico. Se midieron el plano sagital, el plano transversal y el eje del riñón. Todas las mediciones se analizaron según edad, sexo, índice de masa corporal, obesidad y consumo de alcohol. Los valores medios de edad, talla, peso e índice de masa corporal se calcularon como 44,39 años, 167,05 cm, 74,23 kg y 27,06 kg/m2 en las mujeres, respectivamente. Las mismas variable fueron 44,13 años, 167,70 cm, 75,93 kg y 26,71 kg/m2. Hubo diferencias significativas entre las características demográficas, el sexo y el consumo de alcohol en términos de diámetro anteroposterior del hígado, diámetro transversal de la vena porta del lado derecho y exploración transversal del hígado. Además, algunas mediciones, incluido el diámetro transversal de la vena porta, la exploración transversal del hígado y la exploración longitudinal del hígado en el eje del riñón, mostraron diferencias significativas entre los grupos de edad. Hubo diferencias significativas en el eje diagonal y el diámetro anteroposterior del hígado, el diámetro interno de la vena porta y los parámetros de las exploraciones hepáticas longitudinales del plano aórtico entre situaciones de obesidad. Los hallazgos obtenidos proporcionarán valores de referencia importantes y útiles ya que pueden determinar algunas anomalías relacionadas con enfermedades hepáticas. Además, los valores de edad, sexo, obesidad e índice de masa corporal pueden ser eficaces en los parámetros relacionados con la morfometría del hígado y la vena porta.

Liver Anatomy 2.0 Quiz: Test Your Knowledge.

The liver is one the largest organs in the abdomen and the most frequent site of metastases for gastrointestinal tumors. Surgery on this complex and highly vascularized organ can be associated with high morbidity even in experienced hands. A thorough understanding of liver anatomy is key to approaching liver surgery with confidence and preventing complications. The aim of this quiz is to provide an active learning tool for a comprehensive understanding of liver anatomy and its integration into clinical practice.

Living liver donor hilar anatomical variations and impact of variant anatomy on transplant outcomes.

Donor anatomy is an essential part of donor selection and operative planning in living donor liver transplantation. In this study, variations of hilar structures, and the effects of variant anatomy on donor and recipient outcomes were evaluated. Living donor liver transplantations in a single center between January 2013 and December 2020 were retrospectively reviewed. In total, 203 liver transplantations were analyzed. Type 1 arterial anatomy, type 1 portal vein anatomy and type 1 bile duct anatomy were observed in 144 (70.9%), 173 (85.2%), and 129 (63.5%) donors, respectively. Variant biliary anatomy was observed more frequent in donors with variant portal vein branching than in those with type 1 portal anatomy (60.0% vs 32.3%, P = .004). The overall survival rates calculated for each hilar structure were similar between recipients receiving grafts with type 1 anatomy and those receiving grafts with variant anatomy. When donors with variant anatomy and donors with type 1 anatomy were compared in terms of hilar structure, no significant difference was observed in the frequency of complications and the frequency of serious complications. Biliary variations are more common in individuals with variant portal vein anatomy. Donor anatomic variations are not risk factors for inferior results of recipient survival or donor morbidity.

Portal and Hepatic Venous Territorial Mapping in Healthy Human Livers: Virtual Three-Dimensional Computed Tomography Size-Shape-Topography Study.

OBJECTIVES: This study aimed to assess portal and hepatic venous volumes as related to the planning of complex liver resections and segmental liver transplant. MATERIALS AND METHODS: We analyzed 3-dimensional computed tomography of portal and hepatic vein territorial maps of 140 potential living related liver donors. Portal and hepatic vein maps were simulated both separately and in overlap (cross-mapping) to calculate inflow and outflow volumes. RESULTS: In total liver volume, the right hemiliver was always dominant (mean 64.7 ± 4.8%) and the right medial sector (mean 36.4 ± 6.8%) and segment 8 (mean 19.1 ± 4.3%) accounted for the largest volumes, whereas the left medial sector(mean 13.5 ± 3.1%) and segment 4A (mean 5.8 ± 1.8%) accounted for the smallest volumes (with exclusion of caudate lobe). The right hepatic vein was dominant for both right hemiliver and right lateral sector and had the largest drainage volume in total liver volume (mean 40.0 ± 11.2%). The left hepatic vein was dominant for both left hemiliver and left lateral sector but had the smallest drainage volume fortotal liver volume (mean 21.3 ± 5.0%). The middle hepatic vein drained 50.2 ± 12.5% of the right medial sector and 75.8 ± 15.4% of the left medial sector. In 67 cases, an accessory vein (inferior hepatic vein) drained 16.5 ± 13.2% ofthe right hemiliver, 31.4 ± 25.1% ofthe right lateral sector, 26.6 ± 23.2% of segment 7, and 37.4 ± 31.3% of segment 6. CONCLUSIONS: The portal and hepatic vein territorial anatomy was characterized by extensive individual variability. An extremely smallremnant volume (<25% of total liver volume) precluded a minority of virtual extended left and a majority of extended right hepatectomies. Left trisectionectomy was associated with risky drainage from the middle hepatic vein, extensive segment 6 remnant congestion volume in 8% of cases, and right lateral sector-favorable inferior hepatic vein large drainage pattern in 13% of livers.

Current role of intraoperative ultrasonography in hepatectomy.

Hepatectomy had a high mortality rate in the previous decade because of inadequate techniques, intraoperative blood loss, liver function reserve misdiagnoses, and accompanying postoperative complications. However, the development of several modalities, including intraoperative ultrasonography (IOUS), has made hepatectomy safer. IOUS can provide real-time information regarding the tumor position and vascular anatomy of the portal and hepatic veins. Systematic subsegmentectomy, which leads to improved patient outcomes, can be performed by IOUS in open and laparoscopic hepatectomy. Although three-dimensional (3D) computed tomography and gadoxetic acid-enhanced magnetic resonance imaging have been widely used, IOUS and contrast-enhanced IOUS are important modalities for risk analyses and making decisions regarding resectability and operative procedures because of the vital anatomical information provided and high sensitivity for liver tumors, including "disappearing" liver metastases. Intraoperative color Doppler ultrasonography can be used to delineate the vascular anatomy and evaluate the blood flow volume and velocity in hepatectomy patients and recipients of deceased- and living-donor liver transplantation after vessel reconstruction and liver positioning. For liver surgeons, IOUS is an essential technique to perform highly curative hepatectomy safely, although recent advances have also been made in virtual modalities, such as real-time virtual sonography with 3D visualization.

Study of the human liver by ultrasound examination to search for variations of venous anatomy.

INTRODUCTION: Knowledge about venous patterns (especially portal and hepatic venous) and their variations are extremely crucial for liver transplantation and other surgical procedures on liver. Studies have been done at national or international level on variations of hepatic venous patterns by CT or MRI or by dissection on cadaveric liver. No definitive or authentic study on this topic could be noted in electronic and print media, as well as in standard textbook. Considering low cost and noninvasive nature, we utilized ultrasonography to bridge this lacuna. AIM: To estimate prevalence and types of anatomical variations of hepatic venous system and to determine association of among variations. MATERIALS AND METHODS: It is an observational cross-sectional study where ultrasonographic evaluation of hepatic venous pattern on adult population of either sex (consecutive sampling) without any major liver disorders was done in RG Kar Medical College and data were analyzed with appropriate statistical procedures. RESULTS: Normal hepatic venous pattern along with normal portal venous pattern is much higher in our study, which is a unique finding. The proportion of normal portal venous pattern is more in extra hepatic bifurcation group. Variations of portal vein and normal hepatic venous pattern are more in case of intrahepatic bifurcation of portal venous branching group. Overall presence of intrahepatic bifurcation of portal vein is significantly higher than extrahepatic bifurcation. CONCLUSIONS: This study provides an updated database for the prevalence and distribution of anatomic variations of the hepatic venous and portal venous system.

Re-evaluation of the Couinaud classification for segmental anatomy of the right liver, with particular attention to the relevance of cranio-caudal boundaries.

BACKGROUND: Although the Couinaud classification of liver segments has been challenged by several studies, whether the cranio-caudal boundaries can be delineated in the right liver has not yet been assessed. This study scrutinized the third-order branching pattern of the portal vein in the right liver with attention to the validity of cranio-caudal segmentation. METHODS: Three-dimensional reconstruction of the portal vein and hepatic vein, using non-contrast-enhanced magnetic resonance imaging was performed in 50 healthy participants. RESULTS: In the right paramedian sector, the portal vein ramified into 2 thick P8s (P8vent and P8dor) in all the participants. Additional thick P8s that ran laterally and/or medially (P8lat and/or P8med) were observed in 18 (32%) participants. In contrast, multiple thin P5s, ranging in number from 2 to 6 (median, 4), branched from the right paramedian trunk, the right portal trunk, and/or even from P8s. In the right lateral sector, an arch-like type in which multiple P6s ramified from a single thick P7 was observed in 26 (52%) participants. A bifurcation type composed of a single P7 and a single P6 was observed in 23 (46%) participants, and a trifurcation type was observed in 1 participant. CONCLUSION: No clear cranio-caudal intersegmental plane could be delineated in the right liver in most of the participants. The resection of a whole Couinaud segment in the right liver should not be regarded as a systematic, anatomic resection from an oncologic viewpoint. In contrast, detailed information on the third-order portal vein ramification pattern is likely to be helpful when performing smaller anatomic resections.

Study of anatomical variations of hepatic vasculature using multidetector computed tomography angiography.

PURPOSE: Preoperative evaluation of the hepatic vasculature is necessary to minimize mortality and morbidity during various surgeries due to the complexity of liver anatomy. The purpose of our investigation is to determine the anatomical variations in the hepatic vascular system by using multidetector computed tomography. METHODS: In this observational study, 500 patients aged between 1 and 86 years were randomly chosen from a patient population referred for computed tomography angiography for various clinical indications. Multidetector computed tomography angiography examinations were performed using a 128 detector scanner. The area from the lower thoracic spine to symphysis pubis level, with the patient in a supine position, was adopted as the field of view. The percentage of occurrence of each of the vascular variant was determined. RESULTS: Normal arterial anatomy [Type I] was seen in 306 patients [61.2%]. Replaced left hepatic artery from the left gastric artery was the most common variant in our study, which was seen in 57 patients [11.4%]. Classic hepatic venous anatomy was found in 261 [52.2%] patients. An accessory inferior right hepatic vein was found in 110 [22%] patients. A large early branch of segment VIII into middle hepatic vein was found in 157 patients [31.4%]. Extraparenchymal branching of the right anterior portal vein from the left portal vein was the most common anomaly found in 12 [2.4%] patients. CONCLUSIONS: Computed tomography angiography can be used in preoperative evaluation in various hepatobiliary surgeries and interventional procedures, which give a lot of information regarding parenchyma and vascular system.

[Research progress in the Hepatobiliary Surgery operation of hepatic hilar plate system].

An estimate of about 50% of new liver cancer cases worldwide occur in China every year.Surgical resection is still the major treatment choice for longer survival of patients with hepatocellular carcinoma. Blocking hepatic blood flow and reducing intraoperative bleeding ensure the success of the operation. Anatomic separation of hepatic hilar region is the precondition of hepatic inflow occlusion. The hepatic hilar plate system involves a thick layer of connective tissue covering the hepatic inflow ducts of hepatic hilar region. The descending part of hilar plate assists in reducing the anatomical difficulty of the hepatic hilar region. The "forth porta hepatis" that is hidden in the hepatic hilar plate system involves the accumulation area of "short hepatic portal veins" .The communicating branch vessels between the hepatic inflow vessels form the anatomical basis in reducing the indocyanine green fluorescence stain effect.The relatively fixed position of the hepatic portal plate is considered as a positioning marker for accurate liver resection. The intrahepatic Glisson sheath is connected with thick connective tissue of the hepatic portal panel system, and is regarded as the physical barrier in limiting the proliferation and hypertrophy of hepatocytes and continuation of hepatic portal panel system in the liver.This paper summarizes the anatomy and application of hepatic hilar plate system during hepatobiliary surgery.

Does the renal portal valve exist in a raptor species? A study aimed at further evaluating the mechanism of toxicity of diclofenac in vultures.

Diclofenac has been responsible for the deaths of millions of vultures on the Asian subcontinent. While the pathology of toxicity is well described, the mechanism of toxicity remains elusive. However, it was postulated that toxicity could be related to the unique avian renal vascular structure known as the renal portal valve and that that diclofenac altered valve functionality with subsequent renal ischaemia. While plausible, the valva renalis portalis has only been described in a small number of other bird species such as the chicken (Gallus domesticus), the domestic duck (Anas platyrhynchos domesticus) and ostrich (Struthio camelus) but not a raptor. The aim of this study was to evaluate the renal anatomy and related vasculature of the Cape griffon vulture (Gyps coprotheres) (CGV), a species sensitive to the toxic effects of diclofenac, using gross anatomy, histology and vascular casting. The vasculature of the vulture was found to be almost identical to that of the domestic chicken with the valva renalis portalis present in the v. iliaca externa between the v. renalis renalis cranialis and the v. renalis caudalus. The valve was ring-shaped with finger-like processes and histologically was composed of smooth muscle. The valve was also well vascularized and was associated with a nerve plexus. Based on the findings of this study, the proposed mechanism of toxicity is anatomically possible.

Variations of the right branch of hepatic portal vein in children based on three-dimensional simulation technology.

PURPOSE: To study the variations of the right branch of the hepatic portal vein in children. METHODS: A total of 810 children's abdominal CT images were reconstructed with three-dimensional (3D) simulation software, Variations of the right branch of the hepatic portal vein were analyzed and classified. RESULTS: The most common anatomy (type A) was seen in 355 patients (43.83%). Trifurcation in the right anterior portal vein (type B) variation was seen in 250 cases (30.86%). The right posterior portal vein arched without obvious branching (type C) was seen in 71 cases (8.77%). There were 134 special variants (16.54%) named type D, including 14 cases (1.73%) with the right anterior branch in four sub-branches, 13 cases (1.60%) in one trunk and multiple sub-branches, 92 cases (11.36%) originating from the left trunk of the portal vein, and 15 cases (1.85%) with the VI segment of the portal vein originating from the right anterior branch of the portal vein. CONCLUSION: Variations in the right branch of the hepatic portal vein seems to be very frequent. Recognition of such variations is important in the preoperative evaluation of children with surgery planned, because these variations may have implications for anatomy-guided liver resection and for planning the operative approach.

[Surgical anatomy of the right portal vein]. / Khirurgicheskaia anatomiia vetvei vorotnoi veny pravoi doli pecheni.

OBJECTIVE: To study the features of surgical anatomy of intrahepatic segments of right portal vein. MATERIAL AND METHODS: The results of 260 histological examinations including sectional (n=60) and clinical (n=200) surveys were analyzed. Anatomical analysis implied assessment of organometric characteristics including liver weight, length, width and thickness of right and left lobes, division angles of portal vein, the number of branches, length and diameter of the vessels. Clinical examination was based on analysis of splenoportograms and X-ray direct portal venograms. Patients were divided into three groups according to their body type (dolichomorphic, mesomorphic, brachymorphic). RESULTS: Anatomical and clinical surveys confirmed the differences in metric characteristics of portal vascular system depending on the body type. There was medial angulation of the median fissure under 70-85º (78.0±3.4°) in dolichomorphic and mesomorphic patients. Right angle between the median fissure and lower liver surface was observed in brachymorphic subjects. Portal vein division into the branches of the first order to the right of the median fissure was found in 49 cases. Median or left-sided division was noted in other cases. In most cases (n=219), right portal vein dichotomously divided into the right paramedian and right lateral branches. Portal trifurcation was detected in 2.3% of cases, medial translocation of the right paramedian branch - in 1.1% of cases. CONCLUSION: Right liver lobe surgery may be associated with certain technical difficulties due to variable anatomy of the right portal vein. Anatomical and atypical liver resections should be preceded by preoperative identification of individual anatomical variations of the main liver vessels. Contrast-enhanced computed tomography is optimal method for this purpose.

The human liver: vascular anatomy to determine its segments and divisions / El hígado humano: anatomía vascular para determinar sus segmentos y divisiones

This study aims at understanding the vascularization of the human liver to determine the correct way to divide it into "divisions" (sectors) and segments, for which we dissected 250 livers using the acrylic resin injection method. The results showed the role of the "Porta hepatis" in the hepatic vascular distribution, the existence of seven vascular pedicles for seven portal segments, and the role of portal fissures in the parenchymal division of the liver. Our research provides the definition of a portal segment and demonstrates the role of the hepatic portal vein in originating any liver parenchymal division.

Quisimos estudiar la vascularización del hígado humano para determinar la forma correcta de dividirlo en "divisiones" y segmentos, para lo cual disecamos 250 hígados usando técnicas de inyección acrílica. Los resultados mostraron la función de la Porta hepatis en la distribución vascular del hígado, la existencia de siete pedículos vasculares para siete segmentos portales, y el rol de las fisuras portales en la división parenquimal del hígado. Ofrecemos la definición de lo que es un segmento portal y demostramos el rol de la vena porta hepática en originar cualquier división parenquimal del hígado.

New Technique for Management of Separate Right Posterior and Anterior Portal Veins in Pure 3D Laparoscopic Living Donor Right Hepatectomy.

BACKGROUND: Pure laparoscopic donor hepatectomy, including right hepatectomy, is being increasingly performed at experienced centers (Kim et al. Transplantation 101:1106-1110, 2017; Han et al. Medicine (Baltimore) 96:e8076, 2017; Suh et al. Am J Transplant 18:434-443, 2018; Hong et al. Br J Surg 105:751-759, 2018; Lee et al. Transplantation 102:1878-1884, 2018). However, anatomical variations in the portal vein remain major challenges and are regarded as contraindications by some centers. Using a stapler or clip in donors with these anatomical variations may result in kinking of the remnant portal vein due to the thick linear bite, as well as a reduction in the length of the graft portal vein. This report describes a liver donor with separate right posterior and anterior portal veins who underwent pure 3D laparoscopic donor right hepatectomy, focusing on a new technique of managing separate two portal veins. METHODS: A 45-year-old man offered to donate part of his liver to his father, who required a liver transplant for alcoholic liver cirrhosis. The father's Child-Pugh score was 7 and his Model for End-Stage Liver Disease score was 10.7. Donor height was 175.4 cm, body weight was 79.9 kg, and body mass index was 26.0 kg/m2. Preoperative computed tomography and magnetic resonance cholangiopancreatography showed that the donor had separate right posterior and anterior portal veins. Estimated graft-to-recipient weight ratio was 1.4% and remnant liver volume was 35.7%. The entire procedure was performed under 3D laparoscopic view using a flexible scope and real-time indocyanine green fluorescence cholangiography. The right posterior and anterior portal veins were divided using Hem-O-Lok clips. After retrieving the liver, the stumps of the portal veins were replaced with polypropylene sutures, followed by removal of the Hem-O-Lok clips (SNUH technique). RESULTS: The total operation time was 365 min, with no transfusion and no intraoperative complications. The portal veins were divided safely without any torsion or stricture. The stumps of the portal veins were sutured after retrieval of the liver graft, with suturing requiring about 12 min. The donor was discharged on postoperative day 7 with no complications. CONCLUSION: The SNUH technique, consisting of temporary clipping, intracorporeal suturing, and clip removal is safe and useful for pure laparoscopic right hepatectomy in donors with anatomic variations in the portal vein.

Study on the Segmentation of the Right Posterior Sector of the Liver.

BACKGROUND: The border between segments VI and VII of the right posterior sector of the liver is controversial owing to lack of anatomical landmarks. This study aimed to examine the segmentation of the right posterior sector. METHODS: Using three-dimensional software, ramification type of the right posterior portal vein (RPPV) was analysed in 100 patients. RESULTS: A bow-shaped anatomy, in which the RPPV exhibits a downward convex bow shape with several ramifications, was found in 50 patients. A bifurcation anatomy, in which the RPPV bifurcates into the cranial and caudal branches, was observed in 45 patients. In the bow-shaped anatomy, setting the segmentation was difficult due to lack of definite landmarks; thus, the downward portal branches were determined as segment VI branches, while horizontal and upward branches were determined as segment VII branches. In the bow-shaped anatomy, the incidence of full exposure of a thick branch of the right hepatic vein on virtual transection surface was 60.0%, while in the bifurcation anatomy, it was only 11.1%. No relations were observed between RPPV anatomy and main PV/right hepatic vein anatomy. The volumes of segments VI and VII were equal in both the bow-shaped and bifurcation anatomy. CONCLUSIONS: The bow-shaped and bifurcation types are commonly observed in RPPV anatomy. In the bifurcation anatomy, the right posterior sector is divided into segments VI and VII. In the bow-shaped anatomy, setting the segmentation was difficult, thus it may be compelled to be arbitrarily determined.

Allogeneic Venous Grafts of Different Origin Used for Portal Vein Reconstruction After Pancreaticoduodenectomy - Experimental Study.

BACKGROUND: In clinical medicine, little is known about the use of allografts for portal vein (PV) reconstruction after pancreaticoduodenectomy (PD). Portal and caval systems are physiologically different, therefore the properties of allografts from caval and portal systems were studied here in a pig model. MATERIALS AND METHODS: PD with PV reconstruction with allogeneic venous graft from PV or inferior vena cava (IVC) was performed in 26 pigs. Biochemical analysis and ultrasonography measurements were performed during a 4-week monitoring period. Computer simulations were used to evaluate haemodynamics in reconstructed PV and explanted allografts were histologically examined. RESULTS: The native PV and IVC grafts varied in histological structure but were able to adapt morphologically after transplantation. Computer simulation suggested PV grafts to be more susceptible to thrombosis development. Thrombosis of reconstructed PV occurred in four out of five cases in PV group. CONCLUSION: This study supports the use of allografts from caval system for PV reconstruction in clinical medicine when needed.