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.

Laparoscopic donor right hepatectomy in a donor with type III portal vein anomaly: A case report

RATIONALE

Laparoscopic right donor hepatectomy has been reported sporadically in several experienced centers for selected donors. This report introduced a case of a donor with an independent right posterior segmental portal branching from the main portal vein.

PATIENT CONCERNS

A 47-year-old woman volunteered to donate her right liver to her 48-year-old husband.

DIAGNOSES

The recipient has been diagnosed as hepatocellular carcinoma meeting the Milan criteria and hepatitis B virus related cirrhosis.

INTERVENTIONS

The parenchymal transection was performed by ultrasonic aspirator and Hem-o-Lok clips. The right hepatic artery, right hepatic duct, and the anterior and posterior branches of right portal vein were meticulously dissected, clamped, and transected. The right hepatic vein was transected by vascular stapler. A Y-graft of the recipient's own portal confluence was reconstructed with the donor's separate right anterior and posterior portal veins.

OUTCOMES

The donor's operation time was 420 minutes and the warm ischemia time was about 9 minutes. Blood loss was less than 600 ml without transfusion. The donor was discharged at the 10th postoperative day without any complications.

LESSONS

Laparoscopic right hepatectomy for donors with anomalous portal vein branching and subsequent inflow reconstruction for adult living donor liver transplantation is safe and feasible in highly experienced center.

Morphometric evaluation of the portal vein by means of abdominal computed tomographic angiography in dogs free of vascular anomalies

OBJECTIVE To determine the mean diameter of the main portal vein (PV) in healthy dogs by use of CT angiography, identify any associations between PV diameter and certain dog characteristics, and validate a clinically valuable ratio for quantifying the size of the PV. ANIMALS 100 dogs with no hepatic, cardiac, or vascular anomalies that underwent abdominal CT angiography. PROCEDURES Diameters of the main PV, abdominal aorta (Ao), and caudal vena cava (CVC) were measured by 2 observers at a defined location on postcontrast CT angiographic images in axial, sagittal, and transverse planes. Dog characteristics were evaluated for associations with PV diameter, and a PV:Ao diameter ratio was calculated. Intraclass correlations were calculated to assess intra- and interobserver agreement in vessel diameter measurements. RESULTS Mean diameter values were 7.9 mm (range, 4.1 to 14.8 mm) for the PV, 8.9 mm (range, 3.7 to 13.7 mm) for the Ao, and 11.4 mm (range, 4.4 to 22.5 mm) for the CVC. The PV:Ao diameter ratio was 0.91 mm. The PV diameter was significantly associated with dog body weight but not with dog age, sex, or neuter status. Intra- and interobserver reliabilities for measurements of all 3 vessels were considered excellent (intraclass correlation coefficients > 0.85). CONCLUSIONS AND CLINICAL RELEVANCE Findings indicated that the PV:Ao diameter ratio was a repeatable measurement that may be useful for evaluating the size of the portal vasculature in dogs and possibly for distinguishing healthy PVs from abnormal PVs in dogs with hepatic vascular anomalies.

Circumportal pancreas accompanied with pancreas divisum in a deceased donor for islet transplantation

Circumportal pancreas is a rare and previously not well-recognized anatomical variant. In contrast, pancreas divisum is the most frequent anatomical variant in the pancreas. We report a case in which circumportal pancreas was accompanied with pancreas divisum in a deceased donor for islet transplantation. A unique aspect of our case is that the connecting portion behind the portal vein between the pancreas head and body originated from the ventral pancreas. This is the first case report describing a ventral embryogenic origin of the connecting portion of a circumportal pancreas accompanied with pancreas divisum.

Vascular anatomy of the transverse mesocolon and bidirectional laparoscopic D3 lymph node dissection for patients with advanced transverse colon cancer

Laparoscopic D3 lymph node dissection for transverse colon cancer is technically demanding because of complicated anatomy. Here, we reviewed the vascular structure of the transverse mesocolon, explored the extent of the base of the transverse mesocolon, and evaluated the feasibility and oncological safety of D3 lymph node dissection. We retrospectively reviewed the clinical records of 42 patients with advanced transverse colon cancer who underwent curative surgery and D3 dissection at Kyushu University Hospital between January 2008 and December 2015. We examined the venous and arterial anatomy of the transverse mesocolon of each resection and compared surgical outcomes between patients who underwent laparoscopic D3 (Lap D3) and open D3 (Open D3) dissection. Patients included two with Stage I, 18 with Stage II, 20 with Stage III, and two with Stage IVA. Thirty-six (85.7%) and six (14.3%) patients underwent Lap D3 or Open D3, respectively. The tumor sizes of the Open D3 and Lap D3 groups were 7.8 and 3.7 cm, respectively (P < 0.001). The Lap D3 group had significantly less blood loss (26 mL vs 272 mL, P = 0.002). The other outcomes of the two groups were not significantly different, including 3-year overall survival (87.7% vs 83.3%, P = 0.385). We observed four patterns of the middle colic artery (MCA) arising from the superior mesenteric artery (SMA), and the frequency of occurrence of a single MCA was 64.3%. The right-middle colic vein (MCV) was present in 92.9% of resections and served as a tributary of the gastrocolic trunk, and 90.5% of the left MCVs drained into the superior mesenteric vein (SMV). The root of the transverse mesocolon was broadly attached to the head of the pancreas and to the surfaces of the SMV and SMA. Laparoscopic D3 lymph node dissection may be tolerated by patients with advanced transverse colon cancer.

Segmentation of liver and vessels from CT images and classification of liver segments for preoperative liver surgical planning in living donor liver transplantation

BACKGROUND AND OBJECTIVE

The present study developed an effective surgical planning method consisting of a liver extraction stage, a vessel extraction stage, and a liver segment classification stage based on abdominal computerized tomography (CT) images.

METHODS

An automatic seed point identification method, customized level set methods, and an automated thresholding method were applied in this study to extraction of the liver, portal vein (PV), and hepatic vein (HV) from CT images. Then, a semi-automatic method was developed to separate PV and HV. Lastly, a local searching method was proposed for identification of PV branches and the nearest neighbor approximation method was applied to classifying liver segments.

RESULTS

Onsite evaluation of liver segmentation provided by the SLIVER07 website showed that the liver segmentation method achieved an average volumetric overlap accuracy of 95.2%. An expert radiologist evaluation of vessel segmentation showed no false positive errors or misconnections between PV and HV in the extracted vessel trees. Clinical evaluation of liver segment classification using 43 CT datasets from two medical centers showed that the proposed method achieved high accuracy in liver graft volumetry (absolute error, AE = 45.2 ± 20.9 ml; percentage of AE, %AE = 6.8% ± 3.2%; percentage of %AE > 10% = 16.3%; percentage of %AE > 20% = none) and the classified segment boundaries agreed with the intraoperative surgical cutting boundaries by visual inspection.

CONCLUSIONS

The method in this study is effective in segmentation of liver and vessels and classification of liver segments and can be applied to preoperative liver surgical planning in living donor liver transplantation.

CT of the paraumbilical and ensiform veins in patients with superior vena cava or left brachiocephalic vein obstruction

The purpose of this study was to elaborate on the anastomoses between the paraumbilical and systemic veins, particularly the ensiform veins. The connections with the ensiform veins have received little attention in the anatomical and radiological literature, and remain incompletely described. Too small to be reliably traced in normal CT scans, the paraumbilical veins can dilate in response to increased blood flow from systemic veins in superior vena cava obstruction (SVCO), allowing a study of their arrangement and connections. Collateral paraumbilical veins were therefore analyzed retrospectively in 28 patients with SVCO using CT. We observed inferior and superior groups of collateral vessels in 23/28 (82%) and 17/28 (61%) patients, respectively. Inferior veins ascended towards the liver and drained into portal veins (19/28, 68%) or the umbilical vein (8/28, 29%); superior veins descended and drained into portal veins. The inferior veins (N = 27) could be traced to ensiform veins in almost all of the cases (26/27, 96%), and a little over half (14/27, 52%) were also traceable to subcutaneous and deep epigastric veins. They were opacified by ensiform (25/27, 93%), deep epigastric (4/27, 15%) and subcutaneous (4/27, 15%) veins. The superior veins (N = 17) were supplied by diaphragmatic (13/17, 76%) and ensiform veins (4/17, 24%); the diaphragmatic veins were branches of collateral internal thoracic, left pericardiacophrenic and anterior mediastinal veins. Collateral ensiform veins were observed in 22 patients and anastomosed with internal thoracic (19/22, 86%), superior epigastric (9/22, 41%), diaphragmatic (4/22, 18%), subcutaneous (3/22, 14%) and anterior mediastinal veins (1/22, 5%). These observations show that the paraumbilical veins communicate with ensiform, deep epigastric, subcutaneous and diaphragmatic veins, joining the liver to the properitoneal fat pad, anterior trunk, diaphragm and mediastinum. In SVCO, the most common sources of collateral flow to the paraumbilical veins are the ensiform and diaphragmatic branches of the internal thoracic veins.

A Game-Based Approach to Teaching and Learning Anatomy of the Liver and Portal Venous System

Introduction

The use of games and game elements as teaching tools has received increasing attention in the medical education literature. Used formatively, games promote student engagement and satisfaction, and encourage collaboration and teamwork among students. They may also help students retain knowledge, although research supporting this notion is limited. This resource contains a 30-minute interactive lab station involving two different game-based activities aimed at teaching functional anatomy of the liver and portal venous system.

Methods

The first activity is a flipped version of a traditional pinned anatomy practical, wherein students place their own pins on a body donor in response to application-level prompts. The second activity is an outlay-type card game where students assemble cards to depict the venous drainage of gut organs in a healthy patient versus one with portal hypertension.

Results

In end-of-session reviews, several students volunteered feedback that the activities were effective and enjoyable. Additionally, average student scores on two subject exam questions increased by approximately 13% and 4%, compared with students who took the exam before the game elements were introduced.

Discussion

These game-based activities may serve as a starting point for others wishing to deal with historically difficult topics in a more engaging way. The tools presented are low-cost, low-tech, and easy to modify for use with different student populations.

Portal Supply and Venous Drainage of the Caudate Lobe in the Healthy Human Liver: Virtual Three-Dimensional Computed Tomography Volume Study

OBJECTIVE

The venous vascular anatomy of the caudate lobe is exceptional. The purpose of this study was to assess portal inflow and venous outflow volumes of the caudate lobe.

METHODS

Extrahepatic (provided by the first-order branches) versus intrahepatic (provided by the second- to third-order branches) portal inflow, as well as direct (via Spieghel veins) versus indirect (via hepatic veins) venous drainage patterns were analyzed in virtual 3-D liver maps in 140 potential live liver donors.

RESULTS

The caudate lobe has a greater intrahepatic than extrahepatic portal inflow volume (mean 55 ± 26 vs. 45 ± 26%: p = 0.0763), and a greater extrahepatic than intrahepatic venous drainage (mean 54-61 vs. 39-46%). Intrahepatic drainage based on mean estimated values showed the following distribution: middle > inferior (accessory) > right > left hepatic vein.

CONCLUSIONS

Sacrifice of extrahepatic caudate portal branches can be compensated by the intrahepatic portal supply. The dominant outflow via Spieghel veins and the negligible role of left hepatic vein in caudate venous drainage may suggest reconstruction of caudate outflow via Spieghel veins in instances of extended left hemiliver live donation not inclusive of the middle hepatic vein. The anatomical data and the real implication for living donors must be further verified by clinical studies.

Imaging assessment of portal venous system: pictorial essay of normal anatomy, anatomic variants and congenital anomalies

The purpose of this pictorial essay is to describe anatomic variants and congenital anomalies of portal venous system and related liver parenchymal alterations. The imaging findings of some of these entities have been previously described in other articles, however this work encompasses all congenital anomalies of portal venous system with attention to their features on various imaging modalities; in particular we illustrated with detailed pictures all the main portal vein variants, congenital extra- and intra-hepatic porto-systemic venous shunts and portal vein aneurysm. Variants of portal branches and intrahepatic portosystemic shunts are quite uncommon, however, when present, they should be recognized before performing surgery or interventional procedures. Congenital absence of the portal vein is an important finding as the complete loss of portal perfusion predisposes the liver to focal or diffuse hyperplastic or dysplastic changes. Portal vein aneurysm is a rare clinical entity that can affect intra- and extra-hepatic portal branches; although usually asymptomatic, thrombosis can occur. Awareness of congenital variants of portal venous system among radiologists should allow a more confident diagnosis and permit an accurate planning of surgical procedures and percutaneous interventions; identification of portal system anomalies also suggest an accurate evaluation of associated hepatic parenchymal anomalies such as nodular regenerative hyperplasia, focal nodular hyperplasia (FNH), and adenomas with high risk of malignant transformation.

New formula for predicting standard liver volume in Chinese adults

AIM

To obtain a reference range of morphological indices and establish a formula to accurately predict standard liver volume (SLV) in Chinese adults.

METHODS

Computed tomography (CT)-estimated total liver volume (CTLV) was determined in 369 Chinese adults. Age, sex, body weight, body height, body mass index, and body surface area (BSA) were recorded using CT. Total splenic volume, portal venous diameter (PVD), splenic venous diameter (SVD), and portal venous cross-sectional area (PVCSA) were also measured by CT. Stepwise multiple linear regression analysis was performed to evaluate the impact of each parameter on CTLV and to develop a new SLV formula. The accuracy of the new formula was compared with the existing formulas in a validation group.

RESULTS

The average CTLV was 1205.41 ± 257.53 cm³ (range, 593.80-2250.10 cm³). The average of PVD, SVD and PVCSA was 9.34 ± 1.51 mm, 7.40 ± 1.31 mm and 173.22 ± 48.11 mm², respectively. The CT-estimated splenic volume of healthy adults varied markedly (range, 46.60-2892.30 cm³). Sex, age, body height, body weight, body mass index, and BSA were significantly correlated with CTLV. BSA showed the strongest correlation (r = 0.546, P < 0.001), and was used to establish a new model for calculating SLV: SLV (cm³) = 758.259 × BSA (m²)-124.272 (R² = 0.299, P < 0.001). This formula also predicted CTLV more accurately than the existing formulas, but overestimated CTLV in elderly subjects > 70 years of age, and underestimated liver volume when CTLV was > 1800 cm³.

CONCLUSION

Our new BSA-based formula is more accurate than other formulas in estimating SLV in Chinese adults.

Portal vein branching order helps in the recognition of anomalous right-sided round ligament: common features and variations in portal vein anatomy

PURPOSE

This study aimed to evaluate the common features and variations of portal vein anatomy in right-sided round ligament (RSRL), which can help propose a method to detect and diagnose this anomaly.

METHODS

In this retrospective study of 14 patients with RSRL, the branching order of the portal tree was analyzed, with special focus on the relationship between the dorsal branch of the right anterior segmental portal vein (P_A-D) and the lateral segmental portal vein (P_LL), to determine the common features. The configuration of the portal vein from the main portal trunk to the right umbilical portion (RUP), the inclination of the RUP, and the number and thickness of the ramifications branching from the right anterior segmental portal vein (P_A) were evaluated for variations.

RESULTS

In all subjects, the diverging point of the P_A-D was constantly distal to that of the P_LL. The portal vein configuration was I- and Z-shaped in nine and five subjects, respectively. The RUP was tilted to the right in all subjects. In Z-shaped subjects, the portal trunk between the branching point of the right posterior segmental portal vein and that of the P_LL was tilted to the left in one subject and was almost parallel to the vertical plane in four subjects. Multiple ramifications were radially distributed from the P_A in eight subjects, whereas one predominant P_A-D branched from the P_A in six subjects.

CONCLUSIONS

Based on the diverging points of the P_A-D and P_LL, we proposed a three-step method for the detection and diagnosis of RSRL.

Jugular and Portal Vein Volume, Middle Cerebral Vein Velocity, and Intracranial Pressure in Dry Immersion

BACKGROUND

The objective was to determine if short term exposure to dry immersion (DI) results in a cephalic fluid shift similar to what has been observed with spaceflight.

METHODS

Data were collected from 10 individuals at rest and during the first 2 h of dry immersion. Jugular vein (JV), portal vein (PV), and thyroid volume were measured using 3D echography. Middle cerebral vein velocity (MCVv) was determined using transcranial Doppler ultrasound. The cochlear response to audio stimulation was used to derive an estimate of intracranial pressure (dICP).

RESULTS

After 2 h of DI, there was a significant increase (mean ± SD) in JV (2.21 ± 1.10 mL), PV (1.05 ± 0.48 mL), and thyroid (0.428 ± 0.313 mL) volume. MCVv was also significantly increased with DI (3.90 ± 5.03 cm · s-1). There was no change in dICP with DI in part due to large individual variability. The range of dICP changes appeared to be related to MCVv, with participants with the largest increase in MCVv also showing increased dICP.

DISCUSSION

The results suggest that DI induces a significant cephalic fluid shift similar to what is observed with spaceflight. The increased thyroid volume suggests that cerebral tissue may also be subjected to similar fluid filtration, with implications for changes in intracranial pressure. However, despite all participants having an increase in JV and thyroid volume, only half showed an increase in dICP, suggesting that increased venous pooling alone is not sufficient to cause increased intracranial pressure.Arbeille P, Avan P, Treffel L, Zuj K, Normand H, Denise P. Jugular and portal vein volume, middle cerebral vein velocity, and intracranial pressure in dry immersion. Aerosp Med Hum Perform. 2017; 88(5):457-462.

Anatomic Peculiarities of Pig and Human Liver

Many investigations on surgical methods and medical treatment are currently done on pigs. This is possible because the pig is sufficiently close genetically to humans. In recent years, progress in liver surgery has opened new possibilities in surgical treatment of liver diseases. Because the methods are relatively novel, various improvements are still needed, and it is thus helpful to conduct experimental surgeries on pig livers. We reviewed the literature to compare the anatomic and functional features of pig and human livers, information that will be of great importance for improving surgical techniques. During the literature review, we used various sources, such as PubMed, Scopus, and veterinary journals. Our results were summarized in diagrams to facilitate understanding of the vascular structure and biliary systems. We conclude that, although the shapes of the human and pig livers are quite different, the pig liver is divided into the same number of segments as the human liver, which also shows a common structure of the vascular system. Thus, with the anatomic and structural features of the pig liver taken into account, this animal model can be used in experimental hepatic surgery.

Sonographic assessment of the portal vein diameter in apparently healthy adults in a Northern Nigerian population

BACKGROUND

Sonography is a valuable tool in the assessment of porto-systemic pathologies. This study aimed at determining the mean portal vein diameter based on age, gender and anthropometric variables.

METHODS

A cross sectional study conducted among 201 apparently healthy adults in Bauchi Metropolis. Participants were recruited from the school of nursing AbubakarTafawa Balewa Teaching Hospital (ATBUTH), Bauchi. Ultrasound machine ALOKA SSD-1000, (IP-1233EV, SN-57324, Japan) with curvilinear transducer with frequency of 3-5MHz was used for a period of four months, (December 2015 to April 2016). Participants' heights were measured while standing against a meter rule with the head in Frankfurts' position and weight measured using a weighing scale. Data analysis was done using SPSS version 22.0. Descriptive statistics (mean, standard deviation), and Pearson's Correlation were used.

RESULTS

The mean portal vein diameter was 9.60 ± 1.41mm for both sexes. The mean value for males was 9.71 ± 1.42mm, and 9.35±1.46mm among females. There was a positive correlation correlation between the PV diameter and Body Mass Index (P ≤ 0.01).

CONCLUSION

This study found the mean values of PV diameter in apparently healthy adults in our environment to be 9.60 ± 1.41mm and that PV diameter positively correlates with anthropometric variables.

[Three-dimensional classification of the right portal vein and liver segmentation based on three-dimensional visualization technology]

OBJECTIVE

To investigate the anatomy of right portal vein based on three-dimensional (3D) visualization technology and provide a morphological basis for computer-assisted individualized liver segmentation and anatomical hepatectomy.

METHODS

Liver CT data of 83 cases were segmented and reconstructed using the medical image three-dimensional visualization system (MI-3DVS), and 3D classifications of the right portal vein were established according to its branch number, direction and distribution. Individualized liver segmentation was performed based on the 3D typing results.

RESULTS

The reconstructed portal vein models were capable of visualizing the fourth-order portal branches. Generally, the third-order right portal branches were classified into P5, P6, P7 and P8 branches. According to the 3D distribution of the branches, P5 branches were classified into types A, B, C, D, and E [in 16 (19.3%), 5 (6%), 30 (36.1%), 7(8.5%), and 25 (30.1%) cases, respectively], P8 branches into types A, B, C, and D [in 29 (34.9%), 29 (34.9%), 10 (12.1%), and 15 (18.1%) cases, respectively], P6 branches into types A, B, C, and D [in 35 (42.2%), 12 (14.5%), 33 (39.7%), and 3 (3.6%) cases, respectively], and P7 branches into types A, B, C, D, E, and F [in 27 (32.5%), 11(33.3%), 27 (32.5%), 4(4.8%), 12 (14.5%), and 2 (2.4%) cases, respectively]. Individualized liver segmentation was achieved based on liver segments supplied by the third-order portal branches.

CONCLUSION

3D classifications of the complex and highly variant anatomy of third-order right portal vein and individualized liver segmentation based on this classification before the operation facilitates successful performance of anatomical hepatectomy.

[Risk factors of persistent thrombocytopenia after adult liver transplantation and prophylactic measures]

OBJECTIVE

To investigate the risk factors associated with persistent thrombocytopenia after liver transplantation (LT), and to explore effective measures for prevention.

METHODS

One hundred and twenty-eight adult patients, who received liver transplantation in our hospital between January 2009 and June 2012 and met the inclusive criteria, were enrolled in the study. The clinical data were retrospectively analyzed, including pre-LT spleen volume, main portal vein size, coronary vein size, platelet and white blood cell levels, total bilirubin level and model of end stage liver disease score. The risk factors associated with persistent thrombocytopenia after LT were evaluated by logistic regression analysis. The effect of simultaneous splenic artery coarctation for high risk patients was evaluated with χ2 test.

RESULTS

Logistic regression analysis showed that per-LT spleen volume larger than 500 ml (P = 0.012, OR=2.789, 95%CI: 1.249-6.227) and portal vein size beyond 15 mm (P = 0.017, OR = 3.124, 95%CI: 1.230-7.933) were independent risk factors for persistent thrombocytopenia after LT. The incidence rate of persistent thrombocytopenia after LT in patients with or without simultaneous splenic artery coarctation were 16.7% (1/6) and 66.7% (32/48), respectively(P < 0.05).

CONCLUSION

Spleen volume larger than 500 ml and portal vein size beyond 15 mm are risk factors for persistent thrombocytopenia after LT. Simultaneous splenic artery coarctation may reduce the occurrence of persistent thrombocytopenia after LT.

Termination of the ligamentum venosum and the topographic relationship between the left portal vein, left hepatic artery, and ligamentum venosum in the fissures for the ligamentum teres and ligamentum venosum

PURPOSE

The aim of this study was to clarify the location of termination of the ligamentum venosum (LV) and topographic relationships between the left portal vein (LPV), left hepatic artery (LHA), and LV in the fissures for ligamentum teres and LV.

METHODS

Anatomical examination was performed on 50 livers from embalmed Korean adult cadavers.

RESULTS

The LV originated from a point between the transverse and umbilical portions of LPV (Tr-Um point) in all specimens, and terminated in the common trunk of the middle hepatic vein and left hepatic vein (LHV) (61%) or in the LHV (39%). In the fissures for ligamentum teres and LV, the courses of the LHA relative to the LV and the LPV varied, such that four main patterns could be discerned. In type I (48%), the LHA crossed the inferior surface of Tr-Um point and passed just left of the origin of LV. In type II (20%), the LHA crossed the inferior surface of umbilical portion of LPV. In type III (10%), the LHA crossed the inferior surface of Tr-Um point to pass just left of origin of LV, with one branch of the right hepatic artery crossing the inferior surface of umbilical portion of LPV. In type IV (12%), no arterial branches ran on the inferior surfaces of transverse and umbilical portions of LPV.

CONCLUSION

These details may play a role as external landmarks for facilitating preestimation of intrahepatic structures during various surgical procedures involving the liver.

Contrast-enhanced magnetic resonance angiography for the preoperative evaluation of hepatic vascular anatomy in living liver donors: a meta-analysis

RATIONALE AND OBJECTIVES

The objective of this study was to determine the diagnostic accuracy of contrast-enhanced magnetic resonance angiography (MRA) when used in the preoperative evaluation of hepatic vascular anatomy in living liver donors.

MATERIALS AND METHODS

A computer-assisted literature searching of EMBASE, PubMed (MEDLINE), and the Cochrane library databases was conducted to identify potentially relevant articles which primarily examined the utility of contrast-enhanced MRA in the preoperative evaluation of hepatic vascular anatomy in living liver donors. We used the Q statistic of chi-squared value test and inconsistency index (I-squared, I(2)) to estimate the heterogeneity of the data extracted from all selected studies. Meta-Disc software (version 1.4) (ftp://ftp.hrc.es/pub/programas/metadisc/Metadisc_update.htm) was used to perform our analysis.

RESULTS

Eight studies were included in the present meta-analysis. A total of 289 living liver donor candidates and 198 patients who underwent liver harvesting were included in the present study. The pooled sensitivities of hepatic artery (HA), portal vein (PV), and hepatic vein (HV) in this meta-analysis were 0.84, 0.97, and 0.94, respectively. The pooled specificities of HA, PV, and HV were 1.00, 1.00, and 1.00, respectively. The pooled diagnostic odds ratios of HA, PV, and HV were 127.28, 302.80, and 256.59, respectively. The area under the summary receiver-operating characteristic curves of HA, PV, and HV were 0.9917, 0.9960, and 0.9813, respectively.

CONCLUSIONS

The high sensitivity and specificity demonstrated in this meta-analysis suggest that contrast-enhanced MRA was a promising test for the preoperative evaluation of hepatic vascular anatomy in living liver donors.

Assessment of normal portal vein diameter in children

BACKGROUND AND AIM

The internal diameter of the portal vein varies with age and anthropometric parameters. The caliber of the normal portal vein in adults has been extensively studied but little is known about portal vein dimensions in the growing child. This study was conducted to establish standards of portal vein diameter by ultrasonography in healthy Indian children based on age, gender and anthropometric parameters.

METHODS

Total 306 healthy children between the age of < 1 month and 12 years, visiting our outpatient departmentor accompanying their siblings were enrolled in the study. The children were distributed into ten age-groups. Each group was further divided in two sub-groups based on gender. Anthropometric parameters including weight, height and chest circumference were measured.Portal vein diameter was assessed by ultrasonography.

RESULTS

The portal vein diameter increases with age, height, weight and chestcircumference. But the values are similar in boys and girls. Multiple logistic regression (adjusted R- square: 0.922) revealed age (p = 0.002), height/length (p < 0.0001), weight (p = 0.011), and chest circumference (p < 0.0001), as independent determinants of portal vein diameter. However, height/length emerged as the most consistent determinant (coefficient of regression: 1.536; p < 0.001; 95% confidence interval: 0.066-0.092).

CONCLUSION

Our results provide a normal range of portal vein diameter according to age, gender and anthropometric parameters. We conclude that portal vein diameter strongly correlates with age and anthropometric variables like height, weight and chestcircumference,with height being the strongest determinant.

[Three-dimensional reconstruction of individual hepatic veins and portal veins system in hepatectomy]

OBJECTIVE

To study the imaging characteristics and variations of individual digitized hepatic vein and portal vein which were reconstructed by medical image three-dimensional visualization system (MI-3DVS), assess the value of MI-3DVS assisted hepatectomy.

METHODS

From June 2008 to September 2012, the clinical data of 81 patients who underwent hepatectomy with the assist of MI-3DVS were retrospectively reviewed. There were 61 male and 20 female patients, and their age were 12-81 years (median 46 years). The patients with malignant tumors were in 69 cases and with benign tumors in 12 cases. The characteristics and variations of individual digitized hepatic vein and portal vein were observed.Omnidirectional rotation of the three-dimensional (3D) model to observe the distribution of intrahepatic venous system as well as the relationship between the tumor and the veins. 3D models were then simulated resection by the Freeform modeling system.

RESULTS

Of all the 81 3D models of the patients, greater posterior hepatic veins appeared in 10 (12.3%) cases, segment VI hepatic vein appeared in 34 (41.9%) cases. The portal vein was separted with the left branch and the right branch in the hilar in 64 cases, the portal trunk was divided into the left branch of portal vein, the right anterior portal branches, the right posterior portal branches trifurcated in 10 cases, the branch of right anterior portal vein start from the left trunk and the branch of right posterior portal vein start from the main trunk independently in 6 cases, there was 1 case, lack of left branch of portal vein. 81 patients underwent hepatectomy with the assist of MI-3DVS, minor hepatectomy in 57 cases, major hepatectomy in 24 cases (comparatively-reduced major hepatectomy in 12 cases). R0-resection was achieved in all of the patients. Both the inflow and the outflow were maintained in the residual liver after the completion of hepatectomy. Postoperative liver failure was observed in none of the patients.

CONCLUSIONS

MI-3DVS in liver resection was the best choice of surgical approach provides an intuitive basis, and it could reduce the risk of surgery to prevent postoperative hepatic failure.

Hemodynamic analysis for transjugular intrahepatic portosystemic shunt (TIPS) in the liver based on a CT-image

In this paper, we apply a 3-D flow model and a 1-D circulation model to the hemodynamic analysis of transjugular intrahepatic portosystemic shunt (TIPS), the therapy for treating acute portal hypertension (PH) induced diseases. Using the 3-D model we are able to simulate the blood flow within a patient-specific TIPS system which was reconstructed from a computed tomography image, and quantify such hemodynamic data as the wall shear stress and flow velocity. The 1-D model is used for the investigation of generic TIPS-induced hepatic circulation phenomena. By incorporating physiological data into the 1-D model we can reproduce some complex flow patterns such as the increased arterial flow after TIPS implantation, the formation of retrograde flow in the portal vein, etc. In particular, our model gives a quantitative analysis of the interplay between TIPS and hepatic flows. In conclusion, the presented computational model can be used for the theoretical analysis of TIPS, in which clinical decisions are often made based on contradictory considerations to balance the procedure-induced complications and the urgency of relieving acute PH symptoms.

Fetal intrahepatic gallbladder and topographical anatomy of the liver hilar region and hepatocystic triangle

The fetal gallbladder (GB) is embedded in a deep fossa surrounded by the liver parenchyma. Using 15 specimens with intrahepatic GB (crown-rump length 45-92 mm; approximately 9-13 weeks of gestation), we assessed the fetal topographical anatomy of the hepatocystic triangle and the porta hepatis. The cystic duct displayed a long upward course (0.9-4.5 mm along the supero-inferior axis) from the GB, along the duodenum, to the common bile duct in the hepatoduodenal ligament, via an independent mesentery separated from liver parenchyma by a recess of the peritoneal cavity. Notably, the course varied in length among specimens, not among stages. At the porta hepatis, we were able to distinguish the supraportal course of the posterior right hepatic duct overriding a portal vein branch to segment 8 (6/15) from the other, infraportal course (9/15). In the latter type, the portal vein bifurcation was superior to the cystic duct course. Two margins of the hepatocyctic triangle were very long in fetuses because of the inferiorly located intrahepatic GB. Thus, the triangle seems to be difficult to identify in prenatal ultrasound. During changes in location after 9 weeks, the GB fundus remains attached to the liver because the cystic artery was often embedded in the liver parenchyma. A failure in the embedding and re-exposure process of the GB may result in anomalous peritoneal folds around the GB.

Vascular mechanisms involved in angiotensin II-induced venoconstriction in hypertensive rats

To investigate the venoconstrictor effect of angiotensin II (Ang II) in spontaneously hypertensive rats (SHR), we used preparations of mesenteric venular beds and the circular muscle of the portal veins. Vessels were tested with Ang II in the presence or absence of losartan, PD 123319, HOE 140, L-NAME, indomethacin, or celecoxib. In the mesenteric venular bed of SHR, the effect of Ang II (0.1 nmol) was nearly abolished by losartan and enhanced by HOE 140, indomethacin, and celecoxib, while PD123319 and L-NAME had no effect. In portal vein preparations, cumulative-concentration response curves (CCRC) to Ang II (0.1-100 nmol/L) exhibited a lower maximal response (E(max)) in SHR compared to Wistar rats. AT(1) receptor expression was similar in the two strains, while AT(2) receptor levels were lower in SHR portal veins when compared to Wistar. In SHR portal veins, losartan shifted the CCRC to Ang II to the right, while indomethacin and HOE 140 increased the E(max) to Ang II. PD 123319, celecoxib, and L-NAME had no effect. Taken together, our results suggest that Ang II-induced venoconstriction in SHR is mediated by activation of AT(1) receptors and this effect may be counterbalanced by kinin B(2) receptor and COX metabolites. Furthermore, our data indicate that there are different cellular and molecular mechanisms involved in the regulation of venous tonus of normotensive and hypertensive rats. These differences probably reflect distinct factors that influence arterial and venous bed in hypertension.

"Supraportal" right posterior hepatic artery: an anatomic trap in hepatobiliary and transplant surgery

BACKGROUND

A supraportal right posterior hepatic artery (RPHA), which runs cranially to the right portal vein and goes to the liver, has never been described.

METHODS

The course of the RPHA to the right portal vein was evaluated, using (1) computed tomography (CT) arteriography and portography in 300 patients who underwent multidetector row CT (radiologic study) and (2) operative records in 203 patients who underwent left-sided hepatectomy for perihilar cholangiocarcinoma (surgical study).

RESULTS

In the radiologic study, an infraportal type RPHA was observed in 239 (79.7%) patients, a supraportal type in 35 (11.7%), and a combined type in 26 (8.7%). In the surgical study, an infraportal type was observed in 179 (88.2%) patients, a supraportal type in 11 (5.4%), and a combined type in 13 (6.4%). In two patients with the combined type RPHA, the supraportal hepatic artery of the right posterior superior segment (A7) was injured during surgery. In another two patients with advanced carcinoma involving the supraportal PRHA, combined hepatic artery resection and reconstruction was necessary. Overall, in 4 (17.4%) of the 24 hepatectomized patients with supraportal or combined type RPHA, iatrogenic injury during surgery or cancer invasion of the hepatic artery occurred due to the course of the RPHA itself. In contrast, 179 hepatectomized patients with infraportal type RPHA did not have such course-dependent complications.

CONCLUSIONS

The supraportal RPHA runs just beneath the right hepatic duct, which may function as an anatomic trap during hepatobiliary and transplant surgery.

Preoperative estimation of the liver graft weight in adult right lobe living donor liver transplantation using maximal portal vein diameters

An accurate preoperative estimate of the graft weight is vital to avoid small-for-size syndrome in the recipient and ensure donor safety after adult living donor liver transplantation (LDLT). Here we describe a simple method for estimating the graft volume (GV) that uses the maximal right portal vein diameter (RPVD) and the maximal left portal vein diameter (LPVD). Between June 2004 and December 2009, 175 consecutive donors undergoing right hepatectomy for LDLT were retrospectively reviewed. The GV was determined with 3 estimation methods: (1) the radiological graft volume (RGV) estimated by computed tomography (CT) volumetry; (2) the computed tomography-calculated graft volume (CGV-CT), which was obtained by the multiplication of the standard liver volume (SLV) by the RGV percentage with respect to the total liver volume derived from CT; and (3) the portal vein diameter ratio-calculated graft volume (CGV-PVDR), which was obtained by the multiplication of the SLV by the portal vein diameter ratio [PVDR; ie, PVDR = RPVD(2) /(RPVD(2) + LPVD(2) )]. These values were compared to the actual graft weight (AGW), which was measured intraoperatively. The mean AGW was 633.63 ± 107.51 g, whereas the mean RGV, CGV-CT, and CGV-PVDR values were 747.83 ± 138.59, 698.21 ± 94.81, and 685.20 ± 90.88 cm(3) , respectively. All 3 estimation methods tended to overestimate the AGW (P < 0.001). The actual graft-to-recipient body weight ratio (GRWR) was 1.00% ± 0.19%, and the GRWRs calculated on the basis of the RGV, CGV-CT, and CGV-PVDR values were 1.19% ± 0.25%, 1.11% ± 0.22%, and 1.09% ± 0.21%, respectively. Overall, the CGV-PVDR values better correlated with the AGW and GRWR values according to Lin's concordance correlation coefficient and the Landis and Kock benchmark. In conclusion, the PVDR method is a simple estimation method that accurately predicts GVs and GRWRs in adult LDLT.

[Study on risk factors of early complications after surgery for schistosomal portal hypertension]

OBJECTIVE

To explore the related factors of early complications after surgery for schistosomal portal hypertension, so as to provide a scientific basis for prevention of postoperative complications and development of perioperative prevention programe.

METHODS

Case data of patients with schistosomal portal hypertension in Xiangyue Hospital affiliated to Hunan Institute of Parasitic Diseases from January, 2000 to September, 2009 were collected. With single factor analysis and relevant professional knowledge, related factors were analysed with logistic regression analysis.

RESULTS

A total of 52 related factors from the data of 323 cases were analysed with univariate analysis, indicating that 17 factors, including sex, history of bleeding, history of smoking, history of ascites, preoperative length of stay, diameter of portal vein, A/G ratio, albumin, total bilirubin, blood ammonia, total bile acid, operative mode, blood loss, blood transfusion, size of the right liver, postoperative analgesia, time of indwelling gastric tube, were related to the incidence of postoperative complications (all P values < 0.05). Logistic regression results showed the portal vein diameter, A/G ratio, bleeding history, blood loss, time of indwelling gastric tube were risk factors of postoperative complications within 30 days. Postoperative analgesia was considered as the protection factor.

CONCLUSIONS

The patients with larger portal vein diameter, lower of A/G ratio, history of bleeding, more loss of blood, longer retention with gastric tube have greater risk of postoperative complication. Loss of blood in operation was the greatest risk, but postoperative analgesia was the protection factor.

[Three-dimensional reconstruction and anatomic variation of the portal vein based on 64-slice spiral CT data]

OBJECTIVE

To investigate the three-dimensional reconstruction methods of the portal vein using 64-slice spiral CT data and the anatomical variation of the portal vein.

METHODS

Three-dimensional reconstruction of the portal vein was performed using Mimics software based on the 64-slice spiral CT data of 64 cases. Each model of the portal vein and its branches was evaluated according to the presentation rate, depiction quality and anatomic variation.

RESULTS

The reconstructed model showed a depiction rates of 100% for the 4-grade branches of the portal vein. The stem of the portal vein and the left and right branches of the level III or above were all displayed, but in 2 cases the superior mesenteric vein and in 1 case the spleen vein was displayed only to the level IV. Of the 64 cases, 50 (78.1%) had normal portal vein and 14 (21.9%) showed anatomical variations.

CONCLUSION

The 3D model vividly mimics the anatomic variations of the portal vein to provide valuable information for surgical plans.

Anatomy and variation of right posterior portal vein in Chinese population

BACKGROUND/AIMS

Our assessment of the segmental anatomy of the liver will allow more systematic and limited segmentectomies, as well as a safer harvesting for liver sectors in LDLT.

METHODOLOGY

We have examined 104 patients with normal intrahepatic vascular anatomy by helical CT scans and another 12 cases of cadaveric livers dissected to examine their bifurcation characteristics.

RESULTS

In 61 out of 104 (59%) cases, we have found out that the right posterior portal vein does not have obvious isolated bifurcation branches which can determine the boundary between the 6th and the 7th graft. In 8 out of 12 (66.6%) cadaveric livers cases, the RPV runs through the right posterior segment without any other large branches while the rest of them form an actinomorphic bifurcation.

CONCLUSION

Because of the major discrepancies that occurred in determining the boundary between the 6th and 7th segment, we propose a creative assessment of the segment of the right hemiliver and consider the right posterior graft as a unique segment.

Relationship of hepatic functional parameters with changes of functional liver volume using technetium-99m galactosyl serum albumin scintigraphy in patients undergoing preoperative portal vein embolization: a follow-up report

BACKGROUND

To identify predictors of changes in functional hepatic volumes after portal vein embolization (PVE) before hepatectomy, we examined the relationship between hepatic functional parameters and changes in functional volume of the embolized and non-embolized liver based on a previous volumetric analysis.

MATERIAL AND METHODS

Subjects were 24 patients who underwent PVE, which was performed through the trans-ileocolic vein (n = 4) or by percutaneous transhepatic puncture (n = 20). The RI liver volume parameter was measured by liver scintigraphy with technetium-(99m) galactosyl human serum albumin ((99m)Tc-GSA). Computed tomography (CT) volume parameter was also measured.

RESULTS

Significant atrophy of the embolized liver and hypertrophy of the non-embolized liver (change of 72 ± 108 cm(3) and 111 ± 91 cm(3), respectively) (change of 7.8%) was observed after PVE. The change in these RI volume parameters (change of 173 ± 175 cm(3) and 145 ± 137 cm(3) , respectively) (16.5%) was significantly greater than CT volume parameters (P < 0.01). CT vol and RI vol in the embolized and non-embolized liver were well correlated (r = 0.75 and 0.69, respectively). However, the correlation between CT and RI volume parameters in the embolized and non-embolized liver after PVE was very weak (r = 0.17 and 0.03, respectively). Only alkaline phosphatase level correlated negatively with atrophic CT volume parameter of the embolized liver (r = -0.455, P < 0.05). When compared with CT volume parameter, more parameters were significantly correlated with changes of RI volume parameter in the embolized liver: pre-PVE pressure; ICGR15; and serum levels of hyaluronate, total bilirubin, albumin, and alkaline phosphatase. Only platelet count was significantly correlated with hypertrophy of the non-embolized liver.

CONCLUSION

RI volume parameter might more accurately reflect functional changes in the embolized liver and non-embolized liver than CT volume parameter. Correlated parameters might allow us to predict the functional effect of PVE.

Mesopancreas: myth or reality?

CONTEXT

A recently published study hypothesized the concept of 'mesopancreas', defining it as a firm, well-vascularized structure extending from the posterior surface of the pancreatic head to behind the mesenteric vessels.

OBJECTIVE

To verify and define mesopancreas from resection specimens obtained from fresh cadavers.

DESIGN

Postmortem anatomical-pathological study.

SETTING

Department of Surgery in conjunction with the Departments of Forensic Medicine and Pathology, Government Medical College and Hospital, Jabalpur, MP, India.

PARTICIPANTS

Twenty fresh adult cadavers without any intra-abdominal injury or gross intra-abdominal pathology.

INTERVENTIONS

Specimens containing the entire duodenum, pancreatic head and neck, gallbladder, cystic duct, common bile duct, superior mesenteric vessels, inferior vena cava and aorta were removed en-bloc. Gross and histopathological examinations of the specimens were carried out.

MAIN OUTCOME MEASURES

To look for a fibrous sheath or fascia around the retropancreatic structure purported to be a mesopancreas.

RESULTS

Loose areolar tissue, adipose tissue, peripheral nerve, nerve plexus, lymphatic and capillaries were found in the retropancreatic tissue, extending from the head, neck and uncinate process of pancreas to the aorto-caval groove but no fibrous sheath or fascia was found around these structures.

CONCLUSIONS

The concept of 'mesopancreas' is anatomically unfounded.

Advanced surface reconstruction technique to build detailed surface models of the liver and neighboring structures from the Visible Korean Human

Unlike volume models, surface models, which are empty three-dimensional images, have small file size, so that they can be displayed, rotated, and modified in a real time. For the reason, the surface models of liver and neighboring structures can be effectively applied to virtual hepatic segmentectomy, virtual laparoscopic cholecystectomy, and so on. The purpose of this research is to present surface models of detailed structures inside and outside the liver, which promote medical simulation systems. Forty-seven chosen structures were liver structures such as portal triad, hepatic vein, and neighboring structures such as the stomach, duodenum, muscles, bones, and skin. The structures were outlined in the serially sectioned images from the Visible Korean Human to prepare segmented images. From the segmented images, serial outlines of each structure were stacked; on the popular commercial software, advanced surface reconstruction technique was applied to build surface model of the structure. A surface model of the liver was divided into eight models of hepatic segments according to distribution of the portal vein. The surface models will be distributed to encourage researchers to develop the various kinds of medical simulation of the abdomen.

Portal vein branching pattern in anomalous right-sided round ligament

OBJECTIVE

To study the relationship of anomalous right-sided round ligament with respect to branches of the portal vein.

METHODS

We studied four patients of right-sided round ligament diagnosed radiologically in the last 5 years. 3-D volume rendered CECT abdominal images were analyzed for attachment of the round ligament in the liver in relation to portal venous anatomy and position of gallbladder.

RESULTS

In all cases, a trifurcate pattern of portal venous branching was observed. Right-sided round ligament was attached at the point of divergence of the right anterior portal vein. The region to the left of the point of its attachment drained into the middle hepatic vein while the region to the right of the point of attachment drained into the right hepatic vein. The left portal vein branched into posterior and paramedian branches. Right, middle, and left hepatic veins were visualized having normal course in all cases. In all, the gallbladder was present to the left of the round ligament.

CONCLUSIONS

Trifurcate pattern of portal vein branching in all four cases. Right-sided round ligament was attached to the bifurcation of the right anterior portal vein in all the cases. The left portal vein branched into posterior and paramedian branches.

3D anatomical variations of hepatic vasculature and bile duct for right lateral sector of liver with special reference to transplantation

To achieve a safer living related liver transplantation (LRLT) using the right lateral sector, anatomical variations of the portal vein, hepatic artery and bile duct for the right lateral sector and their three dimentional (3D) relationship were assessed by integrated 3D-CT images. 52 patients who underwent contrast enhanced multi-detector row CT (MD-CT) and MD-CT cholangiography were enrolled. Data from contrast enhanced MD-CT were used to reconstruct the 3D images of the hepatic artery and portal vein. 3D images reconstructed from MD-CT data of the hepatic artery, portal vein and bile duct were integrated into a single image. The dual branching of the right lateral portal vein was observed in 22 (42.3%) patients. Three (5.8%) had dual right lateral ducts and 14 (26.9%) had dual right lateral arteries. Among them, "south-turning" artery and "north-turning" bile duct was observed in 22 (42.3%). "South-turning" artery and "south-turning" bile duct were 3 (5.8%). "North-turning" artery and "north-turning" bile duct were 2 (7.4%). Only 27 (51.9%) had single portal vein, bile duct and artery for the right lateral sector, those were preferable as candidates for right lateral sector graft transplantation. 3D anatomical variations of portal vein, artery and bile duct for the right lateral sector were complexed, and only half of the donor candidates had preferable hepatic structures for right lateral sector graft transplantation. Understanding of the 3D hepatic structures by 3D-CT may contribute to a better definition of anatomical contraindications for LRLT which may further results in more safe and widely applied right lateral sector graft LRLT.

[Anatomy of the liver: what you need to know]

A precise knowledge of arterial, portal, hepatic and biliary anatomical variations is mandatory when a liver intervention is planned. However, only certain variations must be searched when a precise intervention is planned. The basic liver anatomy as well as the most relevant malformations will be precised.

Dissection of the uncinate process and pancreatic head behind the portal vein using endovascular staplers

Pancreatic resections have evolved into safe operations in experienced centers. Technical refinements continue to further improve operating time, intraoperative blood loss, and outcome after these procedures. The dissection of the uncinate process/pancreatic head is one of the critical steps during pancreaticoduodenectomy. This step can be time-consuming, with the possibility of troublesome hemorrhage. This article describes, in a stepwise fashion, the use of endovascular stapler devices that facilitate uncinate process/pancreatic head dissection during pancreaticoduodenectomy.

Living donor liver transplantation for children in Brazil weighing less than 10 kilograms

Infants with end-stage liver disease represent a treatment challenge. Living donor liver transplantation (LDLT) is the only option for timely liver transplantation in many areas of the world, adding to the technical difficulties of the procedure. Factors that affect morbidity and mortality can now be determined, which opens a new era for improvement. We have accumulated an 11-year experience with LDLT for children weighing<10 kg. From October 1995 to October 2006, a total of 222 LDLT in patients<18 years of age were performed; 129 primary LDLT and 7 retransplants (4 LDLT and 3 deceased donor grafts) were performed in 129 infants weighing<10 kg. Forty-seven patients received grafts with graft-to-recipient weight ratio (GRWR) of >4%. Two patients received monosegmental grafts, and 2 patients underwent delayed abdominal wall closure. Portal vein thrombosis occurred in 5.4% of the patients, hepatic artery thrombosis in 3.1%, and both in 1.5%. Among several variables studied, only the bilirubin level at the time of transplantation was associated with increased risk of death (P=0.009). Grafts with GRWR>4% had no negative effect on patient survival. There were 7 retransplants, and 4 patients received a second parental LDLT. Patient survival rates at 1, 3, and 10 years after transplantation were 88.8%, 84.7%, and 82% for all children, and 87.5%, 84.9%, and 84.9% for infants weighing<10 kg. LDLT has results comparable to other modalities of liver transplantation in infants. Monosegment grafts were rarely required in this series, although they may be necessary in patients with lower body weight.

An anomalous case of the hepatic artery arising from the superior mesenteric artery

In a stdudenet course of gross anatomy dissection at Kanagawa Dental College in 2006, we found an extremely rare case of the hepatic artery arising from the superior mesenteric artery of a 78-year-old Japanese male cadaver. This case belonged to type V in Adachi's classification of the celiac trunk and the superior mesenteric artery (1928). The gastro-splenic trunk and hepato-mesenteric trunk both arose from the abdominal aorta and the left gastric artery arose from the gastro-splenic trunk. The hepatic artery arose from the hepato-mesenteric trunk and crossed the portal vein anteriorly.

An artificial vascular graft is a useful interpositional material for drainage of the right anterior section in living donor liver transplantation

Congestion in the anterior section in a right liver (RL) without a middle hepatic vein (MHV) may lead to graft dysfunction. To solve this problem, an RL draining MHV branches with autologous or cryopreserved vessels can be introduced. However, these vessels are often unavailable, and their preparation is time-consuming. An expanded polytetrafluoroethylene (ePTFE) graft may be used for anterior section drainage. Between February and November 2005, 26 recipients underwent RL liver transplantation draining MHV branches with an ePTFE graft (group P). Twenty-six ePTFE grafts (6 or 7 mm in internal diameter) drained 35 MHV branches on the back table to the graft right hepatic vein or to the recipient's inferior vena cava. The patency of the ePTFE graft was checked with computed tomography scans of the liver. The outcome of group P was compared with those of an RL group with MHV (group M, n=17) and an RL group without reconstruction of MHV or its tributaries (group R, n=85). The 1-month and 4-month patency rates (PRs) of the ePTFE grafts were 80.8% (21/26) and 38.5% (10/26). All showing early obstruction of the ePTFE graft had congestion in the anterior section, but all showing late obstruction were asymptomatic. The 1-month PRs of group P were comparable to, but the 4-month PRs were lower than, those of group M (both 94.1%; P<0.05). However, 1-year patient and graft survival rates of group P (both 100%) were comparable to those of group M (94.1% and 100%) and better than those of group R (83.5% and 88.2%; P<0.05). In conclusion, the early PR of group P was good, and late obstruction of the ePTFE graft had no impact on congestion in the anterior section or patient survival. Therefore, an ePTFE graft may be a useful interposition material for anterior section drainage in RL transplantation without serious complications.

Intraoperative stent placement in the portal vein during or after liver transplantation

The purpose of this research was to evaluate the intermediate effectiveness of intraoperative portal vein stent placement for portal venous stenosis in liver transplantation. We attempted intraoperative portal vein stent placement in 44 portal venous anastomotic stenoses in 36 patients. All patients underwent stent placement via either the inferior or superior mesenteric vein. A total of 22 patients underwent portal vein stent placement simultaneously with liver transplantation, and 14 patients underwent stent placement 1-25 days (mean 5.93 days) after liver transplantation. Of the 22 patients, there was portal vein occlusion in 3 patients and small portal vein (<6 mm) in 10 patients (2.5-5.7 mm; mean size 3.9 mm). Patient follow-up included clinical and laboratory data collection, Doppler ultrasonography (US), and computed tomography (CT). Intraoperative portal vein stent placement was technically successful in all of our study patients, even in 6 patients with total occlusion of the portal vein. A total of 10 study patients underwent thrombectomy of the portal vein, 1 underwent patient portosystemic shunt ligation, and 7 patients had both procedures simultaneously. Portal venous patency has been maintained for 0-56 months (mean 16 months) in 42 (95%) of the 44 stent placements. In conclusion, intraoperative portal vein stent placement is an effective and long lasting treatment modality for treat portal venous stenosis, especially in patients with portal vein occlusion or small sized portal vein.

ENDOSCOPIC ULTRASOUND OF THE CANINE ABDOMEN

The aim of this study was to develop a standardized procedure for examination of the canine abdomen using endoscopic ultrasound and to describe the organs and structures that could be identified transgastrically. The abdomen of four healthy dogs and two cadavers were examined with endoscopic ultrasound. Five anatomic landmarks were used for standardized imaging of the cranial abdomen. These were the portal vein, splenic head and body, duodenum, left kidney, and aorta. High-resolution images of the following organs and structures could be made: distal esophagus, gastric wall from the cardia to the pylorus, liver, caudal vena cava, hepatic lymph nodes, liver hilus, and associated vessels, trifurcation of the celiac artery as well as the path of its branches and the left pancreatic limb and body. Structures that were more difficult to image were the distal duodenum and right pancreatic limb, the entire jejunum, ileum, and cecum as well as the tail of the spleen. Endoscopic ultrasound allowed excellent visualization of the gastric wall and regional structures without interference with gas artefacts. Centrally located organs such as the pancreas could be well examined transgastrically with endoscopic ultrasound without interference by overlying intestinal segments as is common with transabdominal ultrasound.

Radiofrequency ablation (RFA): development of a flow model for bovine livers for extensive bench testing

PURPOSE

To develop a flow model for bovine livers for extensive bench testing of technical improvements or procedure-related developments of radiofrequency ablation excluding animal experiments.

METHODS

The perfusion of bovine livers directly from the slaughterhouse was simulated in a liver perfusion tank developed for the experimental work. The liver perfusion medium used was a Tyrode solution prepared in accordance with physiologic criteria (as for liver transplants) which was oxygenated by an oxygenator and heated to 36.5 degrees C. Portal vein circulation was regulated via a flow- and pressure-controlled pump and arterial circulation using a dialysis machine. Flow rate and pressure were adjusted as for the physiology of a human liver converted to bovine liver conditions. The fluid discharged from the liver was returned into the perfusion system through the vena cava. Extendable precision swivel arms with the radiofrequency probe attached were mounted on the liver perfusion tank. RFA was conducted with the RF3000 generator and a 2 cm LeVeen needle (Boston Scientific, Ratingen, Germany) in a three-dimensional grid for precise localization of the generated thermolesions.

RESULTS

Four bovine livers weighing 8.4 +/- 0.4 kg each were prepared, connected to the perfusion system, and consecutively perfused for the experiments. Mean arterial flow was 569 +/- 43 ml/min, arterial pressure 120 mmHg, portovenous flow 1440 +/- 305 ml/min, and portal pressure 10 mmHg. Macroscopic evaluation after the experiments revealed no thrombi within the hepatic vessels. A total of 136 RF thermolesions were generated with an average number of 34 per liver. Mean RF duration was 2:59 +/- 2:01 min:sec with an average baseline impedance of 28.2 +/- 3.4 ohms. The mean diameter of the thermolesions along the puncture channel was 22.98 +/- 4.34 mm and perpendicular to the channel was 23.27 +/- 4.82 mm.

CONCLUSION

Extracorporeal perfusion of bovine livers with consecutive standardized RF ablation was feasible. The bovine liver flow model seems to allow extensive, standardized evaluation of technical or procedure-related developments of RF systems.

Gross anatomy of the portal vein and hepatic artery ramifications in dogs: corrosion cast study

The anatomical variations of the portal vein and the hepatic artery ramifications were analysed on liver corrosion casts in 20 dogs as a possible aid in the surgical management of the organ. The portal vein ramified similarly in all dogs. It divided into the smaller right portal branch from which vessels for the caudate process and both right lobes arose and the substantial left portal branch, which supplied the remaining liver portions and in 12 cases also the dorsal part of the right lateral lobe. Right lateral, right medial and left branches are the major arteries originating from the hepatic artery; however, their origin and course varied among individual animals. In 10 livers, the right lateral and the left branches originated from the hepatic artery, while the right medial branch arose from the left branch and usually supplied the right medial lobe solely. In nine livers, the right medial branch arose directly from the hepatic artery and supplied quadrate lobe and gallbladder as well, while in one liver the common artery, which subsequently divided into lobar branches, branched away from the hepatic artery. An additional branch for the caudate process, originating directly from the hepatic artery, was observed in 10 livers. Certain liver portions received the arterial blood from two major branches, which was particularly characteristic for the right medial lobe (six livers) and caudate process (10 livers). The course of the major arterial branches was also variable, although they proceeded in close anatomical relationship with the portal vein branches. The left arterial branch accompanied the left portal branch on its dorsal aspect (15 cases) or crossed it from the caudal aspect (five cases). The right lateral branch crossed the initial parts of the left and right portal branches either from cranial (12 cases) or caudal aspects (eight cases), while the right medial branch always crossed the left portal branch from its caudal aspect.