Quantitative anatomy of the large variant right hepatic vein: A systematic three-dimensional analysis.

Anatomical variations of the right hepatic vein, especially large variant right hepatic veins (≥5 mm), have important clinical implications in liver transplantation and resection. This study aimed to evaluate anatomical variations of the right hepatic vein using quantitative three-dimensional visualization analysis. Computed tomography images of 650 patients were retrospectively analyzed, and three-dimensional visualization was applied using the derived data to analyze large variant right hepatic veins. The proportion of the large variant right hepatic vein was 16.92% (110/650). According to the location and number of the variant right hepatic veins, the configuration of the right hepatic venous system was divided into seven subtypes. The length of the retrohepatic inferior vena cava had a positive correlation with the diameter of the right hepatic vein (rs = 0.266, p = 0.001) and the variant right hepatic veins (rs = 0.211, p = 0.027). The diameter of the right hepatic vein was positively correlated with that of the middle hepatic vein (rs = 0.361, p < 0.001), while it was inversely correlated with that of the variant right hepatic veins (rs = -0.267, p = 0.005). The right hepatic vein diameter was positively correlated with the drainage volume (rs = 0.489, p < 0.001), while the correlation with the variant right hepatic veins drainage volume was negative (rs = -0.460, p < 0.001). The number of the variant right hepatic veins and their relative diameters were positively correlated (p < 0.001). The volume and percentage of the drainage area of the right hepatic vein decreased significantly as the number of the variant right hepatic vein increased (p < 0.001). The findings of this study concerning the variations of the hepatic venous system may be useful for the surgical planning of liver resection or transplantation.

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.

Impact of the inferior vena cava morphology on fluid dynamics of the hepatic veins.

We reported previously that a large vertical interval between the hepatic segment of the inferior vena cava (IVC) and right atrium (RA), referred to as the IVC-RA gap, was associated with more intraoperative bleeding during hemi-hepatectomy. We conducted a computational fluid dynamics (CFD) study to clarify the impact of fluid dynamics resulting from morphologic variations around the liver. The subjects were 10 patients/donors with a large IVC-RA gap and 10 patients/donors with a small IVC-RA gap. Three-dimensional reconstructions of the IVC and hepatic vessels were created from CT images for the CFD study. Median pressure in the middle hepatic vein was significantly higher in the large-gap group than in the small-gap group (P = 0.008). Differences in hepatic vein pressure caused by morphologic variation in the IVC might be one of the mechanisms of intraoperative bleeding from the hepatic veins.

Hepatic venous reconstruction of the left lateral segment with emphasis on anomalous hepatic vein in pediatric liver transplantation.

Left lateral segment grafts have become a suitable option in pediatric liver transplantation (PLT). The correlation between hepatic vein (HV) reconstruction and outcome is relevant when assessing the safe use of these grafts. We retrospectively reviewed the medical records prospectively collected from a pediatric living donor liver transplantation database and conducted a comparative analysis of the different left lateral segment graft types according to HV reconstruction. Donor, recipient, and intraoperative variables were analyzed. Post-transplant outcomes included vascular complications such as hepatic vein outflow obstruction, early (≤30 d) and late (>30 d) PVT, hepatic artery thrombosis, and graft survival. From February 2017 to August 2021, 303 PLTs were performed. According to venous anatomy, the distribution of the left lateral segment was as follows: single HV (type I) in 174 (57.4%), close HVs, simple venoplasty for reconstruction (type II) in 97 (32.01%), anomalous hepatic vein (AHV) with a distance between the HVs orifices that allowed simple venoplasty (type IIIA) in 25 (8.26%) and AHV with a distance between the HVs orifices requiring homologous venous graft interposition (type IIIB) in 07 (2.31%) grafts. Type IIIB grafts came from male donors ( p =0.04) and had a higher mean donor height ( p =0.008), a higher mean graft weight, and a higher graft-to-recipient weight ratio, both p =0.002. The median follow-up time was 41.4 months. The overall cumulative graft survival was 96.3%, and comparative graft survival showed no difference (log-rank p =0.61). No hepatic vein outflow obstructions were observed in this cohort study. There was no statistically significant difference in the post-transplant outcomes between the graft types. The venous reconstruction of the AHV with homologous venous graft interposition had similar outcomes in the short and long term.

Outcomes of transjugular liver biopsies for liver transplant recipients with bicaval and piggyback hepatic vein anastomoses.

BACKGROUND: Liver transplant hepatic venous anastomoses are usually created using "bicaval" or "piggyback" techniques, which may result in unfavorable angulation between the inferior vena cava and hepatic veins, and makes hepatic vein catheterization and tissue sampling during transjugular liver biopsy (TLB) technically challenging. PURPOSE: To compare the technical successes and complications of TLBs for recipients of liver transplants with bicaval and piggyback hepatic vein anastomoses. MATERIAL AND METHODS: Information on type of hepatic vein surgical anastomosis was available for 190 adult patients in whom 306 consecutive TLBs were performed during 2009-2017: 158 with bicaval and 148 with piggyback anastomoses. The primary outcome of procedural success was defined as obtaining a tissue sample sufficient to make a pathologic diagnosis. RESULTS: A technical success rate of 97% with adequate liver tissue for diagnosis was similar between the anastomotic groups (P = 0.50). TLB was unsuccessful in 3% of patients with piggyback anastomoses due to unfavorable hepatic venous anatomy whereas biopsy was successful in all patients with bicaval anastomoses (P = 0.02). Fluoroscopy times were not significantly different (12.1 vs. 13.9 min, P = 0.08). Rates of major complication were similar between the two groups (3% vs. 3%, P > 0.99). CONCLUSION: TLB is safe and effective for liver transplant patients regardless of the type of hepatic vein anastomosis. While failure to catheterize or advance the stiffened biopsy cannula into the hepatic vein is more likely to occur in patients with piggyback anastomoses, this is a rare occurrence.

Relationship between hepatic venous anatomy and hepatic venous blood loss during hepatectomy.

PURPOSE: Predicting increased blood loss based on anatomical intervascular relationships is essential in major hepatectomy. METHODS: We assessed 63 consecutive patients undergoing anatomical hepatectomy exposing the hepatic vein (HV) trunk at two institutes. Correlations between anatomical alterations of the hepatic inferior vena cava (IVC), HV, hepatic IVC, or right atrium (RA) and the blood loss per standard weight (BLSW) or blood transfusion (n = 18) were analyzed. The results of IVC partial clamping (PC) were additionally examined. RESULTS: The BLSW in type V-up anatomical morphology was significantly higher than that in straight type (p < 0.05). The parameters associated with an increased BLSW (> 13.5 mL/kg) were tumor size (> 4 cm), prothrombin activity (< 87%), CVP (> 7 mmHg), area of suprahepatic IVC (< 360 mm2), IVC-RA gap (> 28 mm), longitudinal angle of IVC (< 160°), and axial angle of the MHV (< 55°). A multivariate analysis revealed that a high IVC-RA gap was a significant independent risk factor (odds ratio; 4.32, p < 0.05). Among 25 patients undergoing IVC-PC, only three showed a remarkable decrease in hepatic venous bleeding. No other statistically significant differences in the surgical records were observed in most cases. CONCLUSION: The IVC-RA gap might be a promising novel predictive parameter reflecting increased blood loss leading to blood transfusion in anatomical hepatectomy.

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.

Hepatic "hot-spot" on angio-computed tomography: the role of inferior Sappey's and ensiform veins.

Hepatic "hot spots" in anterior paraumbilical hepatic segments of patients suffering from superior vena cava syndrome may be revealed by angio-computed tomography. They may be due to a collateralizing system, the epigastric-paraumbilical venous system (EPVS), which enters the liver as a "third inflow". We report a typical case emphasizing the role of the ensiform and inferior Sappey's veins which constitute typical anatomic components of the EPVS.

Perceptions of porta-celiac vascular models for hepatic surgery and their use in residency training.

BACKGROUND: Primary aspect of hepatic navigation surgery is the identification of source vascular details to preserve healthy liver which has a vascular anatomy quite challenging for the young surgeons. The purpose was to determine whether three-dimensional (3D) vascular pattern models of preoperative computed tomography (CT) images will assist resident-level trainees for hepatic surgery. METHODS: This study was based on the perception of residents who were presented with 5 different hepatic source vascular patterns and required to compare their perception level of CT, and 1:1 models in terms of importance of variability, differential of patterns and preoperative planning. RESULTS: All residents agree that models provided better understanding of vascular source and improved preplanning. Five stations provided qualitative assessment with results showing the usefulness of porta-celiac models when used as anatomical tools in preplanning (p = 0.04), simulation of interventional procedures (p = 0.02), surgical education (p = 0.01). None of the cases had scored less than 8.5. Responses related to understanding variations were significantly higher in the perception of the 3D model in all cases, furthermore 3D models were more useful for seniors in more complex cases 3 and 5. Some open-ended answers: "The 3D model can completely change the operation plan" One of the major factors for anatomical resection of liver transplantation is the positional relationship between the hepatic arteries and the portal veins. CONCLUSION: The plastic-like material presenting the hepatic vascularity enables the visualization of the origin, pattern, shape, and angle of the branches with appropriate spatial perception thus making it well-structured.

Right hepatic venous system variation in living donors: a three-dimensional CT analysis.

BACKGROUND: The right hepatic venous system consists of the right hepatic vein (RHV) and inferior RHVs (IRHVs). When the right posterior section is used as a graft for liver transplantation, understanding variations and relationships between the RHV and IRHVs is critical for graft venous return and hepatic vein reconstruction. This study aimed to evaluate variations in the hepatic veins and the relationships between them. METHODS: The medical records and CT images of patients who underwent hepatectomy as liver donors were assessed retrospectively. The relationship between the veins was evaluated by three-dimensional CT. RESULTS: The configuration of the posterior section was classified into one of eight types based on the RHV and IRHVs in 307 patients. Type 1a (103 of 307), type 1b (139 of 307) and type 2a (40 of 307) accounted for 91·9 per cent of the total. The diameter of the RHV extending towards the inferior vena cava had a significant inverse correlation with that of the IRHV (r2  = -0·615, P < 0·001). Type 1a, which had no IRHVs, had the RHV with the largest diameter; conversely, type 2a, which had a large IRHV, had the RHV with the smallest diameter. CONCLUSION: The hepatic venous system of the right posterior section was classified into eight types, with an inverse relationship between RHV and IRHV sizes. This information is useful for segment VII resection or when the right liver is used as a transplant graft.

ANTECEDENTES: El sistema venoso hepático derecho consiste en la vena hepática derecha (right hepatic vein, RHV) y las RHVs inferiores (IRHVs). Cuando se utiliza la sección posterior derecha hepática como injerto para el trasplante hepático, es fundamental conocer las variaciones e interrelaciones entre la RHV y las IRHVs para el retorno venoso del injerto y la reconstrucción de la vena hepática. El objetivo de este estudio fue determinar las variaciones en las venas hepáticas y sus interrelaciones. MÉTODOS: Se evaluaron retrospectivamente las historias clínicas y las imágenes de la tomografía computarizada de los pacientes que se sometieron a una hepatectomía como donantes vivos para trasplante hepático. La interrelación entre las venas se evaluó mediante imágenes de CT tridimensional. RESULTADOS: La configuración de la sección posterior clasificó a 307 pacientes en base a la RHV y a las IRHVs. Se clasificaron en 8 tipos, de los cuales el Tipo 1a (103/307), el Tipo 1b (139/307) y el Tipo 2a (40/307) representaron el 92% del total. El diámetro de la RHV que se extiende hacia la vena cava inferior presentó una correlación inversa significativa con la de las IRHV (r2: −0,632, P < 0,0001). El diámetro mayor de la RHV se observó en el Tipo 1a, que no presentaba IRHVs; por el contrario, el diámetro más pequeño se observó en el Tipo 2a que presentaba una IRHV grande. CONCLUSIÓN: El sistema venoso hepático de la sección posterior derecha se clasificó en 8 subtipos con una relación inversa entre los tamaños de la RHV y las IRHV. Esta información es útil cuando se practica una resección del segmento 7 o cuando se utiliza el hígado derecho como injerto para el trasplante.

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.

Venous drainage of the left liver: an evaluation of anatomical variants and their clinical relevance.

AIM: To evaluate the variations in venous drainage from the left liver. MATERIALS AND METHODS: A retrospective evaluation was performed of all consecutive abdominal computed tomography (CT) examinations at a tertiary referral facility between 1 January and 30 June 2018. Osirix (Pixmeo SARL, Bernex, Switzerland) was used to examine the major hepatic veins and their tributaries in each scan. The classification of variants as proposed by Nakamura and Tsuzuki was used to describe the findings. The following information was collected: ramification pattern, number, length and diameter of middle (MHV) and left (LHV) hepatic vein tributaries. Two researchers collected data independently, and the average measurements were used as the final dimensions. RESULTS: Of 102 examinations evaluated, only 27 demonstrated the conventional venous drainage patterns. The LHV and MHV combined to form a common trunk that emptied into the inferior vena cava (IVC) in 75 (73.5%) cases. The common trunk had a mean length of 8.89 mm and mean diameter of 20.18 mm. Other patterns included Nakamura and Tsuzuki type I (27.5%), type II (29.4%) and type III variants (16.7%). In addition, 4.9% of patients had absent superior middle veins and 80% had supernumerary short hepatic veins (4%). CONCLUSION: Only 26.5% of patients in this population had conventional venous drainage from the left liver. Surgeons and radiologists in hepatobiliary practice should be aware of these variants in order to minimise morbidity when performing invasive procedures.

Right anatomical hepatectomy: pioneers, evolution, and the future.

To identify the pioneers of right anatomical hepatectomy (RAH), and clarify the development of associated operative procedures, concepts, and the future, we reviewed the "hidden" literature published in Eastern and Western countries since the 1940s. We searched the English and non-English literature on RAH through web search engines, text books and documents, and also referred to experts' comments. Non-English literature, other than in Japanese, was translated. Changes in the anatomical concept, anatomical identification, vascular control technique, approaches, pre-operative management, and other aspects of RAH were analyzed. Honjo and Lortat-Jacob, in 1949 and 1951, respectively, reported the first cases of successful RAH; since then, RAH has been used in the treatment of liver malignancies worldwide. Vascular in-flow control is divided into intrafascial, extrafascial or transfissual access. The anatomical border along the main hepatic veins was proposed for transection, and anterior approaches have been suggested as alternative options in the hazardous situation of right liver rotation. In the laparoscopic era, several procedures and positions have been devised for RAH. In summary, RAH and related anatomical hepatectomy have been established as treatment methods for 70 years, and the future of RAH includes new concepts, approaches, and techniques to optimize patient safety and disease curability.

Hepatic vein in living donor liver transplantation.

Right lobe living donor liver transplantation (LDLT) is a major development in adult LDLT that has significantly increased the donor pool by providing larger graft size and by decreasing risk of small-for-size graft syndrome. However, right lobe anatomy is complex, not only from the inflow but also from the outflow perspective. Outflow reconstruction is one of the key requirements of a successful LDLT and venous drainage of the liver graft is just as important as hepatic inflow for the integrity of graft function. Outflow complications may cause acute graft failure which is not always easy to diagnose. The right lobe graft consists of two sections and three hepatic venous routes for drainage that require reconstruction. In order to obtain a congestion free graft, several types of vascular conduits and postoperative interventions are needed to assure an adequate venous allograft drainage. This review described the anatomy, functional basis and the evolution of outflow reconstruction in right lobe LDLT.

Correlation of clinical features with inferior right hepatic vein incidence: a three-dimensional reconstruction-based study.

PURPOSE: The correlation between right hepatic vein (RHV) diameter and inferior RHV (IRHV) incidence and that between IRHV incidence and other clinical features remain unclear. We investigated factors correlated with IRHV incidence as well as provide a simple and reliable method for predicting IRHV presence preoperatively. METHODS: We obtained computed tomography (CT) imaging data of 1980 patients from the Department of Radiology, Qingdao Municipal Hospital, from July 1, 2016, to July 1, 2017. We excluded patients with heart disease, inferior vena cava (IVC) disease, history of liver surgery or trauma, space-occupying lesions in the liver, and other diseases, which can cause hepatic hemodynamic changes. CT images of patients were three-dimensionally reconstructed. We measured RHV and IRHV diameter as well as the angle between the RHV and the IVC. RESULTS: Data on 299 patients were included in this study; the incidence of IRHV was 34.44%. Sex, age, and the angle between the RHV and IVC did not correlate with IRHV incidence. RHV diameter negatively correlated with IRHV incidence (P < 0.05). The area under the receiver-operating characteristic curve for IRHV incidence was 0.878. The diagnostic threshold value of RHV diameter was 8.86 mm. CONCLUSION: A negative correlation was found between RHV diameter and IRHV incidence, suggesting that IRHV is absent with RHV diameter > 8.86 mm, but is present with RHV diameter < 8.86 mm. This suggests that measuring only RHV diameter can predict the presence of an IRHV when IRHV-related hepatectomy and IRHV preserved living donor liver transplantation are needed.

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 progression and application of Laennec capsule in liver].

The Laennec capsule of liver was first discovered and reported by French doctor Rene Theophile Hyacinthe Laennec in 1802.However, it has not received enough attention for more than 200 years since then. In recent years, with the rapid development of liver surgery represented by laparoscopic technology, and the deepening of the theory of precise liver surgery, the fine anatomical structure of liver Laennec capsule has returned to the vision of liver surgeons.Recent studies have demonstrated the presence of Laennec capsule in liver histology, covering the whole liver surface, and lining the surface of liver parenchyma around the Glisson pedicle and the main hepatic vein along the inflow and outflow channels of the liver. Based on the Laennec capsule approach, it is expected to unify the current approach of Glisson pedicle and the approach of hepatic vein, and provide a new theoretical basis for the liver surgery, and guide us in the standardization of liver surgeries.

Application of 3-Dimensional Printing in Pediatric Living Donor Liver Transplantation: A Single-Center Experience.

Three-dimensional (3D) printing has been used to support organ transplantations. However, whether it helps remains unclear. This study aimed to present and assess the application of 3D-printed liver models in pediatric living donor liver transplantation (LDLT). The 3D images were printed to touchable liver models with transparent liver parenchyma, specifically colored hepatic vessels, and biliary structures. A total of 30 consecutive recipients were enrolled in the study: 10 were operated on with the support of 3D printing (3D-printing group) and 20 (control group) were operated on without it. Detailed photographs and data of the cases in the 3D-printing group were presented. One patient underwent auxiliary partial orthotopic liver transplantation using the left lobe graft, in which the abdominal cavity model was also printed to test whether the planned graft fit the recipient's abdominal cavity. The 3D-printed models facilitated surgical planning and procedures, particularly in the management of hepatic veins and in the prevention of large-for-size syndrome. The operative time of donors in the 3D-printing group was significantly shorter compared with the control group (2.3 ± 0.4 versus 3.0 ± 0.4 hours; P < 0.001). Inpatient costs for donors in the 3D-printing group were 17.1% lower than those in the control group (34.6 ± 6.6 versus 41.7 ± 10.4 thousand ¥; P = 0.03). In conclusion, in small infants and complicated pediatric LDLT patients, 3D-printed models can help minimize the risk of large-for-size syndrome and graft reduction. The 3D-printed models may be conducive to liver graft procurement and intraoperative assistance in pediatric LDLT.

Inferior right hepatic vein on routine contrast-enhanced CT of the abdomen: prevalence and correlation with right hepatic vein size.

AIM: To determine the prevalence of the inferior right hepatic vein (IRHV) in patients undergoing routine contrast-enhanced computed tomography (CECT) of the abdomen and to compare it with the size of the right hepatic vein (RHV). MATERIALS AND METHODS: Two hundred and twenty-four consecutive patients who underwent routine CECT abdomen, with adequate venous opacification, were included in the study. The number and diameter of IRHVs and the diameter of the RHV was noted in each case. RESULTS: A total of 214 IRHVs were detected in 126 cases (56.2%) with a mean diameter of 4.15±1.44 mm. The number of IRHVs ranged from one to four (more than one IRHV was present in 39.7% [50/126] of cases). In approximately one-third of cases (46/126), an IRHV ≥5 mm was found. A weak negative correlation was found between size of the RHV and IRHV (Pearson's correlation coefficient -0.222; p=0.01). The RHV was smaller in size in patients with an IRHV (7.34±1.88 mm) than in patients without an IRHV (8.47±1.99 mm) on CECT abdomen. A larger IRHV was associated with a smaller RHV (6.91±2.05 mm). CONCLUSION: The presence of IRHV on routine CECT abdomen is frequent, and it is not uncommon to encounter more than one IRHV. The diameter of the IRHV has a weak negative correlation with the diameter of the RHV, and a smaller RHV is found in patients with an IRHV.

Segmental branching pattern of the left portal vein: Anatomical characteristics and clinical implications.

The existing knowledge on anatomy of segmental branches of left portal vein (LPV) is limited. This study aims to describe the surgical anatomy and variations of LPV and its segmental branching pattern. Forty fresh cadaveric liver dissections were performed. The dissection of LPV was carried out from its emergence at the level of the portal vein bifurcation to its segmental branches penetrating the left hemiliver. LPV characteristics, the number, and situation of its segmental branches were recorded. LPV comprises two portions: a 28 ± 6.7 mm-long transverse portion (TPLPV) and a 34.9 ± 4.4 mm-long umbilical portion (UPLPV). Mean number of LPV branches to segments I, II, III, and IV was 2 ± 1 (1-6), 2 ± 1 (1-4), 2 ± 1 (1-5), and 8 ± 2 (4-14), respectively. A single large vein supplied segment II in 90% of the cases. Segment III constantly had one vein arising from the left horn of UPLPV with mean diameter of 5.9 ± 1.6 mm. Most of the veins to segment IV took origin from the right horn of UPLPV with a mean number of 5 ± 2 (2-8). Segmental veins arising from UPLPV and TPLPV and supplying segment IV were present in 90 and 45% of the cases respectively. Segmental veins arising from LPV are often multiple and variable in position. Detailed knowledge of these veins is mandatory in order successfully perform anatomical liver resections or monosegment graft harvest for pediatric liver transplantation. Clin. Anat. 31: 1122-1128, 2017. © 2017 Wiley Periodicals, Inc.