Hepatic vein variations in 500 patients: surgical and radiological significance

Preoperative imaging of colorectal liver metastases: what the radiologist and the multidisciplinary team need to know

The management of patients with colorectal liver metastases (CRLM) has transformed over the past 2 decades. Advances in surgical techniques, systemic therapies, and local treatments have resulted in a paradigm shift. Disease that would once have been considered terminal is now frequently treated aggressively with both a disease-free and overall survival benefit. In line with the expanding range of treatment options, there has been an increase in the volume and complexity of imaging required in the management of these patients to ensure optimal patient selection and outcome. The radiologist plays a pivotal role in interpreting these studies, conveying the relevant information and informing the discussion at multidisciplinary team meetings. The purpose of this review is to provide an update for radiologists on the current surgical management of patients with CRLM highlighting specific imaging information that is required by the multidisciplinary team when assessing resectability and/or the need for additional liver-directed therapies.

Ultrasound and computed tomography angiography diagnosis of fetal right atrial isomerism with cardiac total anomalous pulmonary venous connection and intestinal malrotation: a case report and literature review

Right atrial isomerism is a rare and severe isomerism. It is frequently associated with complex congenital heart disease and various extracardiac anomalies. Imaging diagnosis of right atrial isomerism is a challenge. Multisystem and complex anomalies in a 24-week-old fetus were diagnosed with prenatal ultrasound, postnatal computed tomography angiography (CTA), and autopsy. The ultrasound detected most major cardiovascular anomalies including right atrial isomerism and total anomalous pulmonary venous connection. The CTA further detected thoracic and abdominal malformations such as bilateral morphologically right bronchus, diaphragmatic hernia, asplenia, midline liver, and intestinal malrotation. The autopsy confirmed both ultrasound and CTA findings with additional findings, namely, bilateral trilobed lungs and bilateral morphological right auricles. Prenatal ultrasound and postnatal CTA can be complementary to each other in detecting multi-system complex anomalies. Their combined use can be useful for prenatal counseling and postpartum management.

Hepatic grooves: An observational study at laparoscopic surgery

BACKGROUND

In traditional descriptions, the upper surface of the liver is smooth and convex, but deep depressions are variants that are present in 5%-40% of patients. We sought to determine the relationship between surface depressions and the diaphragm.

AIM

To use exploratory laparoscopy to determine the relationship between surface depressions and the diaphragm.

METHODS

An observational study was performed in all patients undergoing laparoscopic upper gastro-intestinal operations between January 1, 2023 and January 20, 2024. A thirty-degree laparoscope was used to inspect the liver and diaphragm. When surface depressions were present, we recorded patient demographics, presence of diaphragmatic bands, rib protrusions and/or any other source of compression during inspection.

RESULTS

Of 394 patients, 343 had normal surface anatomy, and 51 (12.9%) had prominent surface depressions on the liver. There was no significant relationship between the presence of surface depressions and gender nor the presence of rib projections. However, there was significant association between the presence of surface depressions and diaphragmatic muscular bands (P < 0.001).

CONCLUSION

With these data, the diaphragmatic-band theory has gained increased importance over other theories for surface depressions. Further studies are warranted using cross sectional imaging to confirm relationships with intersectional planes as well as beta-catenin assays in the affected liver parenchyma.

Liver surface depressions in the presence of diaphragmatic muscular bands on trans-illumination

Traditional descriptions of liver anatomy refer to a smooth, convex surface contacting the diaphragm. Surface depressions are recognized anatomic variants. There are many theories to explain the cause of the depressions. We discuss the theory that these are caused by hypertrophic muscular bands in the diaphragm.

Liver ultrasound: Normal anatomy and pathologic findings

The goal of this article is to give an overview of intraoperative liver ultrasound, including the indications, different ultrasound techniques, and the ultrasound appearance of normal anatomy, more common anatomic variations, and common hepatic tumors.

Intrahepatic and anterior course of the inferior vena cava: CT image and 3D reconstruction of a rare anatomical variation

The widespread use of computed tomography (CT) for diagnosing and screening abdominal conditions often reveals rare, asymptomatic anomalies. There is a wide range of documented congenital variations in the anatomy of the inferior vena cava (IVC) and hepatic veins. In this report, we detail an exceptionally unusual variant of the IVC that follows a frontward and intraliver course, terminating at the anterior section of the right atrium. To gain a deeper insight into this anomaly, we employed 3D reconstruction techniques using the software Slicer and Blender.

Laparoscopic left hemihepatectomy guided by indocyanine green fluorescence: A cranial-dorsal approach

BACKGROUND

Advancements in laparoscopic technology and a deeper understanding of intrahepatic anatomy have led to the establishment of more precise laparoscopic hepatectomy (LH) techniques. The indocyanine green (ICG) fluorescence navigation technique has emerged as the most effective method for identifying hepatic regions, potentially overcoming the limitations of LH. While laparoscopic left hemihepatectomy (LLH) is a standardized procedure, there is a need for innovative strategies to enhance its outcomes.

AIM

To investigate a standardized cranial-dorsal strategy for LLH, focusing on important anatomical markers, surgical skills, and ICG staining methods.

METHODS

Thirty-seven patients who underwent ICG fluorescence-guided LLH at Qujing Second People's Hospital between January 2019 and February 2022 were retrospectively analyzed. The cranial-dorsal approach was performed which involves dissecting the left hepatic vein cephalad, isolating the Arantius ligament , exposing the middle hepatic vein, and dissecting the parenchyma from the dorsal to the foot in order to complete the anatomical LLH. The surgical methods, as well as intra- and post-surgical data, were recorded and analyzed. Our hospital's Medical Ethics Committee approved this study (Ethical review: 2022-019-01).

RESULTS

Intraoperative blood loss during LLH was 335.68 ± 99.869 mL and the rates of transfusion and conversion to laparotomy were 13.5% and 0%, respectively. The overall incidence of complications throughout the follow-up (median of 18 months; range 1-36 months) was 21.6%. No mortality or severe complications (level IV) were reported.

CONCLUSION

LLH has the potential to become a novel, standardized approach that can effectively, safely, and simply expose the middle hepatic vein and meet the requirements of precision surgery.

Recent advances in computerized imaging and its vital roles in liver disease diagnosis, preoperative planning, and interventional liver surgery: A review

The earliest and most accurate detection of the pathological manifestations of hepatic diseases ensures effective treatments and thus positive prognostic outcomes. In clinical settings, screening and determining the extent of a pathology are prominent factors in preparing remedial agents and administering appropriate therapeutic procedures. Moreover, in a patient undergoing liver resection, a realistic preoperative simulation of the subject-specific anatomy and physiology also plays a vital part in conducting initial assessments, making surgical decisions during the procedure, and anticipating postoperative results. Conventionally, various medical imaging modalities, e.g., computed tomography, magnetic resonance imaging, and positron emission tomography, have been employed to assist in these tasks. In fact, several standardized procedures, such as lesion detection and liver segmentation, are also incorporated into prominent commercial software packages. Thus far, most integrated software as a medical device typically involves tedious interactions from the physician, such as manual delineation and empirical adjustments, as per a given patient. With the rapid progress in digital health approaches, especially medical image analysis, a wide range of computer algorithms have been proposed to facilitate those procedures. They include pattern recognition of a liver, its periphery, and lesion, as well as pre- and postoperative simulations. Prior to clinical adoption, however, software must conform to regulatory requirements set by the governing agency, for instance, valid clinical association and analytical and clinical validation. Therefore, this paper provides a detailed account and discussion of the state-of-the-art methods for liver image analyses, visualization, and simulation in the literature. Emphasis is placed upon their concepts, algorithmic classifications, merits, limitations, clinical considerations, and future research trends.

Lumped parameter liver simulation to predict acute haemodynamic alterations following partial resections

Partial liver resections are routinely performed in living donor liver transplantation and to debulk tumours in liver malignancies, but surgical decisions on vessel reconstruction for adequate inflow and outflow are challenging. Pre-operative evaluation is often limited to radiological imaging, which fails to account for post-resection haemodynamic alterations. Substantial evidence suggests post-surgical increase in local volume flow rate enhances shear stress, signalling hepatic regeneration, but excessive shear stress has been postulated to result in small for size syndrome and liver failure. Predicting haemodynamic alterations throughout the liver is particularly challenging due to the dendritic architecture of the vasculature, spanning several orders of magnitude in diameter. Therefore, we developed a mathematical lumped parameter model with realistic heterogeneities capturing inflow/outflow of the human liver to simulate acute perfusion alterations following surgical resection. Our model is parametrized using clinical measurements, relies on a single free parameter and accurately captures established perfusion characteristics. We quantify acute changes in volume flow rate, flow speed and wall shear stress following variable, realistic liver resections and make comparisons with the intact liver. Our numerical model runs in minutes and can be adapted to patient-specific anatomy, providing a novel computational tool aimed at assisting pre- and intra-operative surgical decisions for liver resections.

Technical Tips for Performing Suprahepatic Vena Cava Tumor Thrombectomy in Renal Cell Carcinoma without Using Cardiopulmonary Bypass

Radical nephrectomy with tumor thrombectomy for advanced renal cell carcinoma is an oncologically relevant approach that can achieve long-term survival even in the presence of distant metastases. However, the surgical techniques pose significant challenges. The objective of this clinical review was to present technical recommendations for tumor thrombectomy in the vena cava to facilitate surgical treatment. Transesophageal echocardiography is required to prepare for this procedure. Cardiopulmonary bypass should be considered when the tumor thrombus has invaded the cardiac chamber and clamping is not feasible because of the inability to milk the intracardiac chamber thrombus in the caudal direction. Prior to performing a cavotomy, it is crucial to clamp the contralateral renal vein and infrarenal and suprahepatic inferior vena cava (IVC). If the suprahepatic IVC is separated from the surrounding tissue, it can be gently pulled down toward the patient's leg until the lower margin of the atrium becomes visible. Subsequently, the tumor thrombus should be carefully pulled downward to a position where it can be clamped. Implementing the Pringle maneuver to reduce blood flow from the hepatic veins to the IVC during IVC cavotomy is simpler than clamping the hepatic veins. Sequential clamping is a two-stage method of dividing thrombectomy by clamping the IVC twice, first suprahepatically and then midretrohepatically. This sequential clamping technique helps minimize hypotension status and the Pringle maneuver time compared to single clamping. Additionally, a spiral cavotomy can decrease the degree of primary closure narrowing. The oncological prognoses of patients can be improved by incorporating these technical recommendations.

Swine Partial Liver Transplantation Model for Practicing Living Donor Liver Transplantation Based on a New Liver Segmentation Method

BACKGROUND

Living donor liver transplantation (LDLT) is one of the most technically demanding and complicated procedures. However, unlike deceased donor liver transplantation, there is no suitable animal model for practicing LDLT. Herein, we propose a new liver segmentation method and a feasible pig LDLT model for practicing for LDLT in humans.

METHODS

Four Landrace pigs weighing 25, 25, 27, and 28 kg were used as donors and recipients to establish a partial liver transplantation model. Partial liver transplantation was performed using a right liver and a left liver, respectively, based on a new segmentation system compatible with that of humans.

RESULTS

We established a new segmentation system for porcine liver transplantation and a partial liver transplantation model. For right liver transplantation, 91 and 142 min were required to operate on the donor and recipient, respectively; for left liver transplantation, 57 and 104 min were required to operate on the donor and recipient, respectively. All pigs that underwent partial liver transplantation remained alive until the operation was completed.

CONCLUSIONS

It is expected that this new pig model based on the new segmentation system will be suitable as an educational tool for LDLT training and will replace the existing animal models for partial liver transplantation.

Exposure of the hepatic vein trunk via tracing of its branches: a useful surgical procedure for laparoscopic anatomical hepatectomy

BACKGROUND

Although there are various advantages of laparoscopic liver resection (LLR) over open liver resection, some problems have been reported, such as disorientation and lack of control of bleeding during liver parenchymal dissection. In this study, we discuss a strategy to overcome the disorientation experienced during liver parenchymal dissection, especially in anatomical LLR.

TECHNICAL PRESENTATION

This procedure involves hepatic parenchymal dissection from the hepatic vein branch along its trunk to reveal an important landmark in anatomical LLR. Knowing which region of the liver is perfused into each hepatic vein in preoperative 3D simulation allows the tracing of the hepatic vein branch that naturally leads to the hepatic vein trunk. After that, hepatic resection can be easily completed by dissecting the line connected to the other landmarks, the Glisson branch, the root of the hepatic vein, and the liver demarcation line.

CONCLUSION

In conclusion, this surgical procedure that traces the branch of the hepatic vein exposes the trunk, which makes it a very useful tool for limited laparoscopic anatomical hepatectomy.

Surgical Anatomy of the Liver-Significance in Ovarian Cancer Surgery

INTRODUCTION

Ovarian cancer is the leading cause of death among all gynecological malignancies. Most patients present with an advanced stage of the disease. The routes of spread in ovarian cancer include peritoneal dissemination, direct invasion, and lymphatic or hematogenous spread, with peritoneal and lymphatic spread being the most common among them. The flow direction of the peritoneal fluid makes the right subphrenic space a target site for peritoneal metastases, and the most frequently affected anatomical area in advanced cases is the right upper quadrant. Complete cytoreduction with no macroscopically visible disease is the most important prognostic factor.

METHODS

We reviewed published clinical anatomy reports associated with surgery of the liver in cases of advanced ovarian cancer.

RESULTS

The disease could disseminate anatomical areas, where complex surgery is required-Morrison's pouch, the liver surface, or porta hepatis. The aim of the present article is to emphasize and delineate the gross anatomy of the liver and its surgical application for oncogynecologists. Moreover, the association between the gross and microscopic anatomy of the liver is discussed. Additionally, the vascular supply and variations of the liver are clearly described.

CONCLUSIONS

Oncogynecologists performing liver mobilization, diaphragmatic stripping, and porta hepatis dissection must have a thorough knowledge of liver anatomy, including morphology, variations, functional status, potential diagnostic imaging mistakes, and anatomical limits of dissection.

Prevalence of hepatic vascular anomalies in consecutive contrast-enhanced computed tomography images — a retrospective observational study

Background

Liver is a complex, highly vascular organ, where anatomical variations are the norm. This study aimed to analyze all the three hepatic vascular anatomical variations in a single study which would help us understand the prevalence of hepatic vascular (arterial, portal, venous) anomalies in the population catered to by our institution.

Methods

A retrospective analysis of 545 contrast-enhanced CT scans was done from November 2019 from the institute PACS after satisfying the inclusion and exclusion criteria. The raw imaging data were processed in PACS software — Centricity™ Universal Viewer and Syngo.via Vb20 platform, for axial, coronal, and axial-oblique multiplanar reformation, maximum intensity projection (MIP), and volume rendering (VR) images. Data were analyzed in the three vascular phases to determine the anatomical variations. Analysis was done by two surgical residents in the division of HPB surgery, which was verified by a certified radiologist.

Results

There were no major differences in the prevalence rates of the vascular anomalies across gender and domicile distributions. The prevalence of normal hepatic artery and variant hepatic artery in our study was 69% and 31%, respectively. Accessory left hepatic artery (10%) was the most common hepatic artery variant in our study. Single RHV was seen in 77.4%, and other RHV variants like two RHV with common trunk, two RHV with independent drainage, and three RHV with common trunk contribute 22.6% of our study population. Accessory inferior RHV was seen in 19.8% of the study population. Normal portal vein anatomy was found in 81.1% in our study, and the most common variant in our study population was trifurcation of portal vein (16.1%).

Conclusion

This was the largest study until date from South India, studying all three hepatic vascular anatomical variations in a single study. Variations in the anatomy of hepatic arteries, portal veins, and hepatic veins are common. A good knowledge of the same is necessary especially for a hepatobiliary surgeon or for an interventional radiologist, to plan and avoid complications during a procedure. Preoperative contrast-enhanced CT scan and whenever necessary a VR or a MIP reconstruction will precisely help in identifying these variations.

Counterclockwise modular laparoscopic anatomical mesohepatectomy using combined glissonean pedicle (Takasaki approach) and hepatic vein-guided approaches

Background

Although laparoscopic anatomical hepatectomy (LAH) is widely adopted today, laparoscopic anatomic mesohepatectomy (LAMH) for patients with hepatocellular carcinoma (HCC) remains technically challenging.

Methods

In this study, 6 patients suffering from solitary liver tumors located in the middle lobe of the liver underwent counterclockwise modular LAMH using combined Glissonean pedicle (Takasaki approach) and hepatic vein-guided approaches. In this process, the Glissonean pedicle approach (Takasaki approach) was first used to transect the liver pedicles of segment right anterior (G58) and segment 4 (G4). Second, the hepatic vein-guided approach was performed along the umbilical fissure vein (UFV) to sever the liver parenchyma from the caudal to cranial direction, and the middle hepatic vein (MHV) and anterior fissure vein (AFV) were then disconnected at the root. Last, the hepatic vein-guided approach was once more performed along the ventral side of the right hepatic vein (RHV) to transect the liver parenchyma from the cranial to anterior direction, and the middle lobe of the liver, including the tumor, was removed completely. The entire process was applied in a counterclockwise fashion, and the exposure or transection sequence was G58, and G4, followed by UFV, MHV, AFV, and finally, the liver parenchyma along the ventral side of RHV.

Results

The counterclockwise modular LAMH using combined Glissonean pedicle (Takasaki approach) and hepatic vein-guided approaches was feasible in all 6 cases. The median duration of the operation was 275 ± 35.07 min, and the mean estimated blood loss was 283.33 ml. All of the 6 patients recovered smoothly. The Clavien-Dindo Grade I-II complications rate was up to 33.33%, mainly characterized by postoperative pain and a small amount of ascites. No Clavien-Dindo Grade III-V complications occurred, and the mean postoperative hospital stay was 6.83 ± 1.47 days. Follow-up results showed that the average disease-free survival (DFS) was 12.17 months, and the 21-months OS rate, DFS rate and tumor recurrent rate were 100%, 83.33% and 16.67% respectively.

Conclusions

Counterclockwise modular LAMH using combined Glissonean pedicle (Takasaki approach) and hepatic vein-guided approaches takes the advantages of the two approaches, is a novel protocol for LAMH. It is thought to be technically feasible for patients with a centrally located solitary HCC. The oncologic feasibility of this technique needs to be investigated based on long-term follow-up. A multicenter, large-scale, more careful study is necessary.

Role of CT in Two-Stage Liver Surgery

Complete resection is the only potentially curative treatment for primary or metastatic liver tumors. Improvements in surgical techniques such as conventional two-stage hepatectomy (TSH) with portal vein embolization and ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) promote hypertrophy of the future liver remnant (FLR), expanding resection criteria to include patients with widespread hepatic disease who were formerly not considered candidates for resection. Radiologists are essential in the multidisciplinary approach required for TSH. In particular, multidetector CT has a critical role throughout the various stages of this surgical process. The aims of CT before the first stage of TSH are to define the feasibility of surgery, assess the number and location of liver tumors in relation to relevant anatomy, and provide a detailed anatomic evaluation, including vascular and biliary variants. Volume calculation with CT is also essential to determine if the FLR is sufficient to avoid posthepatectomy liver failure. The objectives of CT between the first and second stages of TSH are to recalculate liver volumes (ie, assess FLR hypertrophy) and depict expected liver changes and complications that could modify the surgical plan or preclude the second stage of definitive resection. In this review, the importance of CT throughout different stages of TSH is discussed and key observations that contribute to surgical planning are highlighted. In addition, the advantages and limitations of MRI for detection of liver metastases and assessment of complications are briefly described. ^©RSNA, 2022.

Surgical relevance of anatomic variations of the right hepatic vein

BACKGROUND

Variations in the anatomy of hepatic veins are of interest to transplant surgeons, interventional radiologists, and other medical practitioners who treat liver diseases. The drainage patterns of the right hepatic veins (RHVs) are particularly relevant to transplantation services.

AIM

The aim was to identify variations of the patterns of venous drainage from the right side of the liver. To the best of our knowledge, there have been no reports on RHV variations in in a Caribbean population.

METHODS

Two radiologists independently reviewed 230 contrast-enhanced computed tomography scans performed in 1 year at a hepatobiliary referral center. Venous outflow patterns were observed and RHV variants were described as: (1) Tributaries of the RHV; (2) Variations at the hepatocaval junction (HCJ); and (3) Accessory RHVs.

RESULTS

A total of 118 scans met the inclusion criteria. Only 39% of the scans found conventional anatomy of the main hepatic veins. Accessory RHVs were present 49.2% and included a well-defined inferior RHV draining segment VI (45%) and a middle RHV (4%). At the HCJ, 83 of the 118 (70.3%) had a superior RHV that received no tributaries within 1 cm of the junction (Nakamura and Tsuzuki type I). In 35 individuals (29.7%) there was a short superior RHV with at least one variant tributary. According to the Nakamura and Tsuzuki classification, there were 24 type II variants (20.3%), six type III variants (5.1%) and, five type IV variants (4.2%).

CONCLUSION

There was significant variation in RHV patterns in this population, each with important relevance to liver surgery. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.

Modified Dual Hepatic Vein Anastomosis in Pediatric Living-Donor Liver Transplantation Using Left Lateral Segment Grafts With Two Wide Orifices

Background: The anatomic variation of hepatic vein in the left lateral segment (LLS) increases the risk of outflow complication in pediatric living liver transplantation (LDLT). Here, we share a modified method for dual hepatic vein reconstruction in pediatric LDLT using LLS with two wide orifices. Methods: From Sep 2018 to Dec 2019, 434 pediatric LDLTs using LLS were performed in our center. Hepatic veins of grafts were classified into three types with emphasis on the number, size, and location of orifices at the cut surface: a single opening (type I, n = 341, 78.57%); two adjacent orifices (type II, n = 66, 15.21%); two wide orifices with orifices distances <20 mm (type IIIa, n = 15, 3.46%); and two wide orifices with orifices distances >20 mm (type IIIb, n = 12, 2.76%). Rv was defined as the ratio of diameter of V2 and V3 (refer to hepatic vein drained segments II and III). We developed a modified dual hepatic vein anastomosis to reconstruct outflow for type IIIb grafts with Rv ≤1. Briefly, the hepatic vein of segment II was anastomosed to the common stump of middle hepatic vein (MHV) and left hepatic vein (LHV), followed by unification of V3 and the longitudinal incision orifice in inferior venous cave (IVC). Results: During median follow-up of 15.6 months (7.5-22.9 months), no hepatic vein complications occurred. Conclusion: This novel modified dual hepatic vein anastomosis could serve as a feasible surgical option for type IIIb LLS grafts with Rv ≤1 in pediatric LDLT.