Concepts for Liver Segment Classification: Neither Old Ones nor New Ones, but a Comprehensive One

Surgery for colorectal liver metastases: Anatomic and non-anatomic approach

Liver resection is potentially curative for patients with colorectal liver metastasis, but an advanced understanding of tumor biology and improved adjuvant therapies have facilitated an ongoing evolution of metastatic resection, even in the setting of a significant metastatic disease burden. As indications for surgery have expanded, preferred techniques and timing have been debated. This commentary reviews the merits of anatomic versus non-anatomic approaches to colorectal liver metastasis resection, considering oncologic outcomes, overall survival, and conflicting theories in the pathophysiology of the metastatic liver spread.

Computer-assisted image-based risk analysis and planning in lung surgery - a review

In this paper, we give an overview on current trends in computer-assisted image-based methods for risk analysis and planning in lung surgery and present our own developments with a focus on computed tomography (CT) based algorithms and applications. The methods combine heuristic, knowledge based image processing algorithms for segmentation, quantification and visualization based on CT images of the lung. Impact for lung surgery is discussed regarding risk assessment, quantitative assessment of resection strategies, and surgical guiding. In perspective, we discuss the role of deep-learning based AI methods for further improvements.

Robotic monosegment donor hepatectomy for pediatric liver transplantation: First report

BACKGROUND

LT for infants less than 5 kg remains a challenge with high technical complication rates, which is further compounded by large-for-size grafts requiring hyper-reduction. The benefits of MIDH especially for standard left lateral segment (LLS) resection have been unequivocally demonstrated. However, given the fine margins of error, the highly challenging technical aspects of anatomical graft reduction test the limits of safety and may not be routinely feasible with the conventional laparoscopic approach.

CASE REPORT

A 14-month-old girl weighing 4.4 kg with extrahepatic biliary atresia was referred to our unit for an LT. Her mother volunteered to donate and the calculated volume of the LLS was 342 ml, with an estimated GRWR of 7.6. Given the extremely high GRWR, a segment II monosegment graft was planned. A RMDH was performed, with a final GRWR of 4. The donor and recipient were discharged on the 5th and 12th post-operative days, respectively.

CONCLUSION

We present the first-ever report of an RMDH. Our report highlights the fact that robotic surgery can safely replicate a highly precise surgical operation, thereby safely pushing the limits of MIDH.

[Systematic review of current trends in preoperative planning of surgery for liver tumors]

The purpose of the study was a systematic review of current trends in preoperative planning of surgery for liver tumors. These data will be valuable to determine the advantages and disadvantages of 3D modeling, augmented reality technology and 3D printing in preoperative planning of surgery for focal liver lesions.

Switching Monopolar No-Touch Radiofrequency Ablation Using Octopus Electrodes for Small Hepatocellular Carcinoma: A Randomized Clinical Trial

INTRODUCTION

A switching monopolar no-touch radiofrequency ablation (RFA) technique is used for small hepatocellular carcinoma (HCC); however, there have not been any randomized clinical trials comparing this technique to the conventional RFA technique.

OBJECTIVE

This study aims to compare the results of two RFA techniques, and to comparatively identify more effective methods to reduce the progression of local tumors associated with small HCC (≤2.5 cm).

METHODS

This prospective randomized clinical trial (NCT03375281) recruited a total of 116 participants (M:F, 93:23; 68.3 ± 8.4 years) between October 2016 and September 2017. The primary outcome was the cumulative incidence of local tumor progression (LTP) after RFA. Secondary outcomes included technical success rate, technique efficacy, and RFA procedure characteristics. Kaplan-Meier analysis and the Cox proportional hazard regression model were used.

RESULTS

The mean follow-up period was 24.1 months. A sufficient ablative margin was more frequently achieved in the no-touch RFA group (57/60 = 95%) than in the conventional RFA group (50/64 = 78.1%) on immediate follow-up CT (p = 0.01). The cumulative incidence of LTP in the no-touch RFA group was significantly lower than that in the conventional RFA group (p = 0.02). In multivariable analysis, no-touch RFA was the only predictive factor for LTP (p = 0.04, hazard ratio = 0.2, 95% confidence interval = 0.04-0.94).

CONCLUSIONS

A switching monopolar no-touch RFA technique is a favorable treatment option and provides lower LTP after RFA compared with conventional RFA for small HCC.

Ultrasound-guided anatomical liver resection using a compression technique combined with indocyanine green fluorescence imaging

BACKGROUND

Anatomical resection (AR) is a recommended surgical treatment for hepatocellular carcinoma (HCC). However, the conventional procedure (dye injection) for AR is difficult to reproduce. As an alternative, the tumour-feeding portal pedicle compression technique (finger-compression technique) has been proposed as an easy and reversible procedure. Here, we propose a new method combining indocyanine green (ICG) imaging with the finger-compression technique.

METHODS

Eligible patients were prospectively enrolled to undergo ICG compression (ICG-C) anatomical hepatectomy for HCC.

RESULTS

Fifteen patients underwent AR using the ICG-C technique. Overall, the surgical procedures included six segmentectomies, seven subsegmentectomies, and two right posterior sectionectomies. The median tumour size was 5.8 cm (range 2-7 cm). All procedures had an R0 margin. There were no major complications among patients, and minor morbidity occurred in three patients.

CONCLUSIONS

ICG-C is a safe, feasible and effective technique for patients eligible for AR.

Venous hepatic segmentation in dogs (Canis lupus familiaris-L. 1758)

The external shape of the liver is varied and determines specific vascular arrangements. This morphological relationship is important to establish hepatic segmentation in different species submitted to surgeries that aim to preserve a larger area of liver parenchyma. After observing 60 livers injected with Neoprene Latex and three plastic moulds obtained by corrosion, eight hepatic venous segments were identified, drained by six hepatic veins agrouped into segmental veins, which drained one sector (segments I, VI, VII and VIII) and intersegmental veins, which drained more than one sector (segments II/III and IV/V). They were described as follows: left intersegmental vein, formed by a segmental vein from the papillary process (segment I), two to three lateral left segmental veins that drained the segment II, and one to five left paramedian segmental veins that drained the segment III; sagittal intersegmental vein, formed by the confluence between segmental vein of the quadrate lobe (segment IV) and the medial right paramedian segmental vein, which derived from the segment V; lateral right paramedian vein drained the dorsocranial sector of the segment VI; the lateral right segmental vein, formed by one to four vessels that drained segment VII, and the segmental vein of the caudate process, which drained the segment VIII. Understanding the number and disposition of the hepatic veins in lobate livers is essential to reduce bleeding risks in surgeries. The nomenclature based on segmentation analogy of non-lobate liver could be less confusing and, therefore, be more useful in the surgical approaches of lobate livers.

[Surgical anatomy of liver segment iv and its importance in hepatobiliary surgery]

The purpose of this article was to describe clinical anatomy of liver segment IV and determine its significance in liver resection surgery and within integrated approach in the treatment of malignancies of this area.

Anatomy of the hepatic arteries and their extrahepatic branches in the human liver: A cadaveric study

BACKGROUND

To describe the hepatic arterial anatomy in detail, tracing the individual hepatic arteries from their origin, extrahepatic course, branching to their segmental territorial supply as applicable to the vascular mapping for hepatic endovascular procedures.

METHODS

The study was conducted on 100 formalin fixed adult cadaveric livers. The hepatic arterial anatomy was dissected from the origin of hepatic arteries up to their segmental branching.

RESULTS

The origin of hepatic arteries was standard in 72% and aberrant in 28% livers. In livers with standard origin, extrahepatic branching of the main hepatic artery was close to the hepatic hilum in 48% and was in the lower part of the hepatoduodenal ligament in 24% livers. The pattern of extrahepatic branching in each type was three and five respectively. Aberrant arterial anatomy was broadly categorized into three groups. The mapping of segmental arterial vascularization of individual hepatic arteries in each type was also done.

CONCLUSIONS

In the present study, an attempt was made to systematically describe the complex hepatic arterial anatomy in a clinically applicable fashion. High variability was seen in the hepatic arterial anatomy at each level, a lot of which could not be included in the current classification systems. The information provided is an important prerequisite for performing accurate intra-arterial hepatic interventions.

[Navigated liver surgery : Current state and importance in the future]

The preoperative computer-assisted resection planning is the basis for every navigation. Thanks to modern algorithms, the prerequisites have been created to carry out a virtual resection planning and a risk analysis. Thus, individual segment resections can be precisely planned in any conceivable combination. The transfer of planning information and resection suggestions to the operating theater is still problematic. The so-called stereotactic liver navigation supports the exact intraoperative implementation of the planned resection strategy and provides the surgeon with real-time three-dimensional information on resection margins and critical structures during the resection. This is made possible by a surgical navigation system that measures the position of surgical instruments and then presents them together with the preoperative surgical planning data. Although surgical navigation systems have been indispensable in neurosurgery and spinal surgery for many years, these procedures have not yet become established as standard in liver surgery. This is mainly due to the technical challenge of navigating a moving organ. As the liver is constantly moving and deforming during surgery due to respiration and surgical manipulation, the surgical navigation system must be able to measure these alterations in order to adapt the preoperative navigation data to the current situation. Despite these advances, further developments are required until navigated liver resection enters clinical routine; however, it is already clear that laparoscopic liver surgery and robotic surgery will benefit most from navigation technology.

Rare anatomic variations of the right hepatic biliary system

PURPOSE

To report rare and clinically significant anatomic variations in the biliary drainage of right hepatic lobe.

METHODS

Unique variations in the extra- and intrahepatic biliary drainage of right hepatic lobe were observed in 6 cadaveric livers during dissection on 100 formalin-fixed en bloc cadaveric livers.

RESULTS

There was presence of aberrant drainage of right segmental and sectorial ducts in four cases and of accessory right posterior sectorial duct in two cases.

CONCLUSIONS

We encountered some extensively complicated biliary drainage of right hepatic lobe, unsuccessful recognition of which can lead to serious biliary complications during hepatobiliary surgeries and biliary interventions.

Ultrasound of Diffuse Liver Disease Including Elastography

Diffuse liver disease is a substantial world-wide problem. With the combination of conventional ultrasound of the abdomen and elastography-appropriate staging of the patient can be assessed. This information allows for the detection of fibrosis as well as prognosis, surveillance, and prioritization for treatment. With the potential for reversibility with appropriate treatment, accurate assessment for the stage of chronic liver disease is critical.

Survival after Resection of Multiple Tumor Foci of Intrahepatic Cholangiocarcinoma

BACKGROUND

Multiple tumor foci of intrahepatic cholangiocarcinoma (ICC) are often considered a contra-indication for resection. We sought to define long-term outcomes after resection of ICC in patients with multiple foci.

METHODS

Patients who underwent resection for ICC between 1990 and 2017 were identified from 12 major HPB centers. Outcomes of patients with solitary lesions, multiple lesions (ML), and oligometastases (OM) were compared. OM were defined as extrahepatic metastases spread to a single organ.

RESULTS

One thousand thirteen patients underwent resection of ICC. On final pathology, 185 patients (18.4%) had ML and 27 (2.7%) had OM. Median survival of patients with a solitary tumor was 43.2 months, while the median survival of patients with 2 tumors was 21.2 months; the median survival of patients with 3 or more tumors was 15.3 months (p < 0.001). Five-year survival was 43.3%, 28.0%, and 8.6%, respectively. The median survival of patients without OM was 37.8 months versus 14.9 months among patients with OM (p < 0.001); estimated 5-year survival was 39.3% and 10.6%, respectively. In multivariable analysis, the presence of two lesions was not an independent poor prognostic factor for OS (HR 1.19; 95%CI 0.90-1.57; p = 0.229). However, the presence of three or more tumors was an independent poor prognostic factor for OS (HR 1.97; 95%CI 1.48-2.64; p < 0.001).

CONCLUSION

Resection of multiple liver tumors for patients with ICC did not preclude 5-year survival: in particular, estimated 5-year OS for resection of two tumors was 28.0%.

Oncologic superiority of anatomic resection of hepatocellular carcinoma by ultrasound-guided compression of the portal tributaries compared with nonanatomic resection: An analysis of patients matched for tumor characteristics and liver function

BACKGROUND

The superiority of anatomic resection compared with nonanatomic resection for hepatocellular carcinoma remains a matter of debate. Further, the technique for anatomic resection (dye injection) is difficult to reproduce. Anatomic resection using a compression technique is an easy and reversible procedure based on liver discoloration after ultrasound-guided compression of the tumor-feeding portal tributaries. We compared the oncologic efficacy of compression technique anatomic resection with that of nonanatomic resection.

METHODS

Among patients with resected hepatocellular carcinoma, patients who underwent compression technique anatomic resection were matched 1-to-2 with nonanatomic resection cases based on the Child-Pugh class, Model for End-Stage Liver Disease score, cirrhosis, hepatocellular carcinoma number (1/>1), and hepatocellular carcinoma size (>30, 30-50, and >50 mm). The exclusion criteria were nonanatomic resection because of severe cirrhosis, major hepatectomy, 90-day mortality (0 compression technique anatomic resection), non-cancer-related death, and follow-up <12 months. A total of 47 patients who underwent compression technique anatomic resection were matched with 94 nonanatomic resection cases.

RESULTS

All patients were Child-Pugh A, and 53% were cirrhotic. Liver function tests and signs of portal hypertension were similar between the groups. There was 1 hepatocellular carcinoma in 81% of the patients, and the hepatocellular carcinoma was ≥30 mm in 68%. Patients undergoing anatomic resection with compression had better 5-year survival (77% vs 60%; risk ratio = 0.423; P = .032; multivariable analysis), less local recurrences (4% vs 20%; P = .012), and better 2-year local recurrence-free survival (94% vs 78%; P = .012). Nonlocal recurrence-free survival was similar between the groups. The compression technique anatomic resection group more often had repeat radical treatment for recurrence (68% vs 28%; P = .0004) and had better 3-year survival after recurrence (65% vs 42%; P = .043).

CONCLUSION

Compression technique anatomic resection appears to provide a more complete removal of the hepatocellular carcinoma-bearing portal territory. Local disease control and survival are better with compression technique anatomic resection than with nonanatomic resection.

Open Liver Resection, Laparoscopic Liver Resection, and Percutaneous Thermal Ablation for Patients with Solitary Small Hepatocellular Carcinoma (≤30 mm): Review of the Literature and Proposal for a Therapeutic Strategy

BACKGROUND

Patients with a single hepatocellular carcinoma (HCC) ≤3 cm and preserved liver function have the highest likelihood to be cured if treated. The most adequate treatment methods are yet a matter that is debated.

METHODS

We reviewed the literature about open anatomic resection (AR), laparoscopic liver resection (LLR), and percutaneous thermal ablation (PTA).

RESULTS

PTA is effective as resection for HCC < 2 cm, when they are neither subcapsular nor perivascular. PTA in HCC of 2-3 cm is under evaluation. AR with the removal of the tumor-bearing portal territory is recommended for HCC > 2 cm, except for subcapsular ones. In comparison with open surgery, LRR has better short-term outcomes and non-inferior long-term outcomes. LLR is standardized for superficial limited resections and for left-sided AR.

CONCLUSIONS

According to the available evidences, the following therapeutic proposal can be advanced. Laparoscopic limited resection is the standard for any subcapsular HCC. PTA is the first-line treatment for deep-located HCC < 2 cm, except for those in contact with Glissonean pedicles. Laparoscopic AR is the standard for deep-located HCC of 2-3 cm of the left liver, while open AR is the standard for deep-located HCC of 2-3 cm in the right liver. HCC in contact with Glissonean pedicles should be scheduled for resection (open or laparoscopic) independent of their size. Liver transplantation is reserved to otherwise untreatable patients or as a salvage procedure at recurrence.

Human liver segments: role of cryptic liver lobes and vascular physiology in the development of liver veins and left-right asymmetry

Couinaud based his well-known subdivision of the liver into (surgical) segments on the branching order of portal veins and the location of hepatic veins. However, both segment boundaries and number remain controversial due to an incomplete understanding of the role of liver lobes and vascular physiology on hepatic venous development. Human embryonic livers (5-10 weeks of development) were visualized with Amira 3D-reconstruction and Cinema 4D-remodeling software. Starting at 5 weeks, the portal and umbilical veins sprouted portal-vein branches that, at 6.5 weeks, had been pruned to 3 main branches in the right hemi-liver, whereas all (>10) persisted in the left hemi-liver. The asymmetric branching pattern of the umbilical vein resembled that of a "distributing" vessel, whereas the more symmetric branching of the portal trunk resembled a "delivering" vessel. At 6 weeks, 3-4 main hepatic-vein outlets drained into the inferior caval vein, of which that draining the caudate lobe formed the intrahepatic portion of the caval vein. More peripherally, 5-6 major tributaries drained both dorsolateral regions and the left and right ventromedial regions, implying a "crypto-lobar" distribution. Lobar boundaries, even in non-lobated human livers, and functional vascular requirements account for the predictable topography and branching pattern of the liver veins, respectively.

Human liver territories: Think beyond the 8-segments scheme

Worldwide, compartmentalization of the human liver into portal venous territories today follows the eight-segments scheme credited to Couinaud. However, there are increasing reports of anatomical, radiological and surgical observations that contradict this concept. This paper presents a viewpoint that enhances understanding of these inconsistencies and can serve as a basis for customized liver interventions. Clin. Anat. 30:974-977, 2017. © 2017 Wiley Periodicals, Inc.

The error analysis of Lobular and segmental division of right liver by volume measurement

The aim of this study is to explore the inconsistencies between right liver volume as measured by imaging and the actual anatomical appearance of the right lobe. Five healthy donated livers were studied. The liver slices were obtained with hepatic segments multicolor-infused through the portal vein. In the slices, the lobes were divided by two methods: radiological landmarks and real anatomical boundaries. The areas of the right anterior lobe (RAL) and right posterior lobe (RPL) on each slice were measured using Photoshop CS5 and AutoCAD, and the volumes of the two lobes were calculated. There was no statistically significant difference between the volumes of the RAL or RPL as measured by the radiological landmarks (RL) and anatomical boundaries (AB) methods. However, the curves of the square error value of the RAL and RPL measured using CT showed that the three lowest points were at the cranial, intermediate, and caudal levels. The U- or V-shaped curves of the square error rate of the RAL and RPL revealed that the lowest value is at the intermediate level and the highest at the cranial and caudal levels. On CT images, less accurate landmarks were used to divide the RAL and RPL at the cranial and caudal layers. The measured volumes of hepatic segments VIII and VI would be less than their true values, and the measured volumes of hepatic segments VII and V would be greater than their true values, according to radiological landmarks. Clin. Anat. 30:585-590, 2017. © 2017 Wiley Periodicals, Inc.

Superselective intra-arterial hepatic injection of indocyanine green (ICG) for fluorescence image-guided segmental positive staining: experimental proof of the concept

BACKGROUND

Intraoperative liver segmentation can be obtained by means of percutaneous intra-portal injection of a fluorophore and illumination with a near-infrared light source. However, the percutaneous approach is challenging in the minimally invasive setting. We aimed to evaluate the feasibility of fluorescence liver segmentation by superselective intra-hepatic arterial injection of indocyanine green (ICG).

MATERIALS AND METHODS

Eight pigs (mean weight: 26.01 ± 5.21 kg) were involved. Procedures were performed in a hybrid experimental operative suite equipped with the Artis Zeego^®, multiaxis robotic angiography system. A pneumoperitoneum was established and four laparoscopic ports were introduced. The celiac trunk was catheterized, and a microcatheter was advanced into different segmental hepatic artery branches. A near-infrared laparoscope (D-Light P, Karl Storz) was used to detect the fluorescent signal. To assess the correspondence between arterial-based fluorescence demarcation and liver volume, metallic markers were placed along the fluorescent border, followed by a 3D CT-scanning, after injecting intra-arterial radiological contrast (n = 3). To assess the correspondence between arterial and portal supplies, percutaneous intra-portal angiography and intra-arterial angiography were performed simultaneously (n = 1).

RESULTS

Bright fluorescence signal enhancing the demarcation of target segments was obtained from 0.1 mg/mL, in matter of seconds. Correspondence between the volume of hepatic segments and arterial territories was confirmed by CT angiography. Higher background fluorescence noise was found after positive staining by intra-portal ICG injection, due to parenchymal accumulation and porto-systemic shunting.

CONCLUSIONS

Intra-hepatic arterial ICG injection, rapidly highlights hepatic target segment borders, with a better signal-to-background ratio as compared to portal vein injection, in the experimental setting.

Representative Sinusoids for Hepatic Four-Scale Pharmacokinetics Simulations

The mammalian liver plays a key role for metabolism and detoxification of xenobiotics in the body. The corresponding biochemical processes are typically subject to spatial variations at different length scales. Zonal enzyme expression along sinusoids leads to zonated metabolization already in the healthy state. Pathological states of the liver may involve liver cells affected in a zonated manner or heterogeneously across the whole organ. This spatial heterogeneity, however, cannot be described by most computational models which usually consider the liver as a homogeneous, well-stirred organ.

The goal of this article is to present a methodology to extend whole-body pharmacokinetics models by a detailed liver model, combining different modeling approaches from the literature. This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales. Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism.

To show that this approach is generally applicable for different physiological processes, we show three applications as proofs of concept, covering a range of species, compounds, and diseased states: clearance of midazolam in steatotic human livers, clearance of caffeine in mouse livers regenerating from necrosis, and a parameter study on the impact of different cell entities on insulin uptake in mouse livers.

The examples illustrate how variations only discernible at the local scale influence substance distribution in the plasma at the whole-body level. In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.

Algorithmically generated rodent hepatic vascular trees in arbitrary detail

Physiologically realistic geometric models of the vasculature in the liver are indispensable for modelling hepatic blood flow, the main connection between the liver and the organism. Current in vivo imaging techniques do not provide sufficiently detailed vascular trees for many simulation applications, so it is necessary to use algorithmic refinement methods. The method of Constrained Constructive Optimization (CCO) (Schreiner et al., 2006) is well suited for this purpose. Its results after calibration have been previously compared to experimentally acquired human vascular trees (Schwen and Preusser, 2012). The goal of this paper is to extend this calibration to the case of rodents (mice and rats), the most commonly used animal models in liver research. Based on in vivo and ex vivo micro-CT scans of rodent livers and their vasculature, we performed an analysis of various geometric features of the vascular trees. Starting from pruned versions of the original vascular trees, we applied the CCO procedure and compared these algorithmic results to the original vascular trees using a suitable similarity measure. The calibration of the postprocessing improved the algorithmic results compared to those obtained using standard CCO. In terms of angular features, the average similarity increased from 0.27 to 0.61, improving the total similarity from 0.28 to 0.40. Finally, we applied the calibrated algorithm to refine measured vascular trees to the (higher) level of detail desired for specific applications. Having successfully adapted the CCO algorithm to the rodent model organism, the resulting individual-specific refined hepatic vascular trees can now be used for advanced modeling involving, e.g., detailed blood flow simulations.

Anatomy of the liver: an outline with three levels of complexity--a further step towards tailored territorial liver resections

The vascular anatomy of the liver can be described at three different levels of complexity according to the use that the description has to serve. The first--conventional--level corresponds to the traditional 8-segments scheme of Couinaud and serves as a common language between clinicians from different specialties to describe the location of focal hepatic lesions. The second--surgical--level, to be applied to anatomical liver resections and transplantations, takes into account the real branching of the major portal pedicles and of the hepatic veins. Radiological and surgical techniques exist nowadays to make full use of this anatomy, but this requires accepting that the Couinaud scheme is a simplification, and looking at the vascular architecture with an unprejudiced eye. The third--academic--level of complexity concerns the anatomist, and the need to offer a systematization that resolves the apparent contradictions between anatomical literature, radiological imaging, and surgical practice. Based on the real number of second-order portal branches that, although variable averages 20, we submit a system called the "1-2-20 concept", and suggest that it fits best the number of actual--as opposed to idealized--anatomical liver segments.