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

Safety and efficacy of laparoscopic portal territory fluorescence navigation-guided anatomical liver resection in hepatocellular carcinoma patients

BACKGROUND

The clinical effectiveness of classic anatomical resection (CAR) of the liver for hepatocellular carcinoma (HCC) has been controversial. Laparoscopic Portal Territory fluorescence navigation-guided anatomical liver resection (LPTAR) has been increasingly applied in clinical practice. However, evidence on the safety and efficacy of LPTAR is lacking.

METHODS

A retrospective cohort study of patients who underwent laparoscopic hepatectomy from December 2018 to December 2022 was conducted. Propensity score matching (PSM) was employed to match patients who underwent LPTAR with patients who underwent CAR. Differences in recurrence-free survival (RFS), overall survival (OS), and perioperative data were evaluated between the LPTAR and CAR groups. Cox regression models were used for univariate and multivariate analyses, as well as subgroup analyses.

RESULTS

Of the 234 patients included in this study, 70 underwent LRTAR, and 164 underwent CAR. After 1:1 PSM, each group contained 59 patients, and perioperative parameters were better in the LPTAR group. Specifically, the LPTAR group had wider resection margins (13.00 cm vs. 11.00 cm, P = 0.023), less blood loss (200 ml vs. 320 ml, P = 0.010), and fewer postoperative complications (33.90% vs. 57.62%, P = 0.016) than did the CAR group. The RFS rates of patients with HCC was also increased by LPTAR. The 1-, 3-, and 5-year RFS rates of the LPTAR group were significantly higher than those of the CAR group (P = 0.002).

CONCLUSION

Accurate preoperative planning and standardized LPTAR technical criteria prolonged RFS in HCC patients, improved the safety of surgery, and reduced surgical stress.

TRAIL REGISTRATION

The study has been prospective registered at Chinese Clinical Trial Registry (https://www.chictr.org.cn/, ChiCTR2400087661).

Liver anatomy for totally laparoscopic segment 7 resection from a caudal magnified view-a 3-dimensional computed tomographic analysis

BACKGROUND

Laparoscopic resection of hepatic segment 7 is considered particularly difficult. We analyzed anatomic variation of this segment in caudally oriented 3-dimensional (3D) magnified computed tomographic (CT) images obtained prior to liver resection.

METHODS

Analysis included 105 patients with preoperative 3D CT evaluation preceding liver resection for hepatobiliary malignancies between April 2021 and April 2024.

RESULTS

Five ramification patterns were evident from a caudal magnified view. Some patients who had multiple segment 7 (S7) portal pedicles and an S7 pedicle branching ventrally posed difficulty in performing segmentectomy for the exact extent of S7. Distance from the point where a perpendicular line from the right rim of the inferior vena cava (IVC) intersected the right posterior portal pedicle to the point of bifurcation of the S6 and 7 pedicles was 34.6 mm (range, 3.9-78.8; mean ± standard deviation, 35.2 ± 14.8 mm). The median angle between the perpendicular line from the right rim of the IVC and the line from the root of the S7 pedicle to the right rim of the IVC was 77° (10-140); the mean ± standard deviation was 75.3° ± 28.1. Differences among ramification patterns also were evident. The angle between the right posterior portal pedicle and the S7 pedicle was 143° (79-215) or 143.3 ± 26.7, and that between S7 and S6 pedicles was 71°(15-123) or 75.5 ± 21.7°, representing relatively little variation.

CONCLUSIONS

Understanding these details of caudal-view anatomy may resolve difficulties and clarify access required for exposing S7 portal pedicles.

Contribution and advances of robotics in percutaneous oncological interventional radiology

The advent of robotic systems in interventional radiology marks a significant evolution in minimally invasive medical procedures, offering enhanced precision, safety, and efficiency. This review comprehensively analyzes the current state and applications of robotic system usage in interventional radiology, which can be particularly helpful for complex procedures and in challenging anatomical regions. Robotic systems can improve the accuracy of interventions like microwave ablation, radiofrequency ablation, and irreversible electroporation. Indeed, studies have shown a notable decrease of an average 30% in the mean deviation of probes, and a 40% lesser need for adjustments during interventions carried out with robotic assistance. Moreover, this review highlights a 35% reduction in radiation dose and a stable-to-30% reduction in operating time associated with robot-assisted procedures compared to manual methods. Additionally, the potential of robotic systems to standardize procedures and minimize complications is discussed, along with the challenges they pose, such as setup duration, organ movement, and a lack of tactile feedback. Despite these advancements, the field still grapples with a dearth of randomized controlled trials, which underscores the need for more robust evidence to validate the efficacy and safety of robotic system usage in interventional radiology.

Ultrasound-guided percutaneous biopsy for focal liver lesions: Adverse events and diagnostic yield in a single-centre analysis

PURPOSE

Ultrasound-guided biopsy of focal liver lesions (FLL) is a well-established procedure with crucial impact on therapeutic decisions. The safety and accuracy depend on needle type, tumour location and comorbidities. Modern oncological concepts often require large tumour specimens which may increase the procedural risk.

MATERIALS AND METHODS

We retrospectively collected data from consecutively scheduled ultrasound-guided FLL biopsies performed in an interdisciplinary ultrasound unit at a university hospital from 2015-2020. We analysed complication rates, diagnostic accuracy, and patient outcome in a one-year period.

RESULTS

Of 426 scheduled interventions, 339 were included: 322 primary biopsies (40% female, median age 65 years, median BMI 25.4 kg/m2) and 17 rebiopsies in cases with undetermined diagnosis. Indications comprised 309 (96%) cases with suspected malignant lesions. Important comorbidities were type 2 diabetes (n = 107, 33%) and cirrhosis (n = 64, 20%). A conclusive histopathological diagnosis was achieved in 270 (84%) cases with a weak association with lesion size (OR 1.12 per cm, 95%CI 0.99-1.27). Greater BMI (OR 0.60 per 10 BMI points, 95%CI 0.34-1.05) showed a trend towards an insufficient diagnosis. Relevant complications occurred in 8 (2.5%) cases (2 major; 1 life-threatening). Multiple passes showed a trend towards adverse events (OR 2.32 for > 1 pass, 95%CI 0.99-5.42). 93 (29%) patients died during a median follow-up of 171 days.

CONCLUSION

Ultrasound-guided FLL biopsy is an efficient and safe diagnostic measure. The limitations of the procedure and its associated risks should be considered in patients with advanced malignancies.

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

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

Petre E, Marinelli B, Sarkar D, Barral M, H Cornelis F. Percutaneous liver interventions with robotic systems: a systematic review of available clinical solutions

OBJECTIVE

Robotic-guided interventions are emerging techniques that are gradually becoming a common tool for performing biopsies and tumor ablations in liver. This systematic review aims to evaluate their advancements, challenges, and outcomes.

METHODS

A systematic review was conducted using the PubMed database to identify relevant articles published between January 2000 and February 2023. Inclusion criteria focused on studies that assessed robotic systems for percutaneous liver biopsies and tumor ablations. Data extraction was performed to collect information on study characteristics; robotic systems; components and software; imaging modality; degree of freedom; and needle insertion methods. The outcome measures analyzed were procedure time, radiation dose, and accuracy.

RESULTS

10 studies met the inclusion criteria. The robotic devices used included MAXIO, EPIONE, ROBIO-EX, AcuBot, and ACE robotic systems. The data set consisted of 429 percutaneous thermal ablations and 57 biopsies, both robot-guided. On average, the mean deviation of probes was reduced by 30% (from 1.6 vs 3.3 mm to 2.4 vs 3.9 mm (p < 0.001)), and 40% (p < 0.05) fewer readjustments were required during the robotic-assisted interventions. Moreover, robotic systems contributed to a reduction in operating time, ranging from 15% (18.3 vs 21.7 min, p < 0.001) to 25% (63.5 vs 87.4 min, p < 0.001). Finally, the radiation dose delivered to both the patient and the operator was decreased by an average of 50% (p < 0.05) compared to manual procedures.

ADVANCES IN KNOWLEDGE

Robotic systems could provide precise navigation and guidance during liver biopsies and percutaneous ablations.

A Lightweight Network for Contextual and Morphological Awareness for Hepatic Vein Segmentation

Accurate segmentation of the hepatic vein can improve the precision of liver disease diagnosis and treatment. Since the hepatic venous system is a small target and sparsely distributed, with various and diverse morphology, data labeling is difficult. Therefore, automatic hepatic vein segmentation is extremely challenging. We propose a lightweight contextual and morphological awareness network and design a novel morphology aware module based on attention mechanism and a 3D reconstruction module. The morphology aware module can obtain the slice similarity awareness mapping, which can enhance the continuous area of the hepatic veins in two adjacent slices through attention weighting. The 3D reconstruction module connects the 2D encoder and the 3D decoder to obtain the learning ability of 3D context with a very small amount of parameters. Compared with other SOTA methods, using the proposed method demonstrates an enhancement in the dice coefficient with few parameters on the two datasets. A small number of parameters can reduce hardware requirements and potentially have stronger generalization, which is an advantage in clinical deployment.

How Much Is Enough? A Surgical Perspective on Imaging Modalities to Estimate Function and Volume of the Future Liver Remnant before Hepatic Resection

Liver resection is the first curative option for most hepatic primary and secondary malignancies. However, post-hepatectomy liver failure (PHLF) still represents a non-negligible postoperative complication, embodying the most frequent cause of hepatic-related mortality. In the absence of a specific treatment, the most effective way to deal with PHLF is its prevention through a careful preoperative assessment of future liver remnant (FLR) volume and function. Apart from the clinical score and classical criteria to define the safe limit of resectability, new imaging modalities have shown their ability to assist surgeons in planning the best operative strategy with a precise estimation of the FLR amount. New technologies leading to liver and tumor 3D reconstruction may guide the surgeon along the best resection planes combining the least liver parenchymal sacrifice with oncological appropriateness. Integration with imaging modalities, such as hepatobiliary scintigraphy, capable of estimating total and regional liver function, may bring about a decrease in postoperative complications. Magnetic resonance imaging with hepatobiliary contrast seems to be predominant since it simultaneously integrates hepatic function and volume information along with a precise characterization of the target malignancy.

Glissonean Pedicle Isolation Focusing on the Laennec's Capsule for Minimally Invasive Anatomical Liver Resection

Background: Inflow control is one of the most important procedures during anatomical liver resection (ALR), and Glissonean pedicle isolation (GPI) is one of the most efficacious methods used in laparoscopic anatomical liver resection (LALR). Recognition of the Laennec's capsule covering the liver parenchyma is essential for safe and precise GPI. The purpose of this study was to verify identification of the Laennec's capsule, to confirm the validity of GPI in minimally invasive surgery, and to demonstrate the value of GPI focusing on the Laennec's capsule using a robotic system that has been developed in recent years. Methods: We used a cadaveric model to simulate the Glissonean pedicle and the surrounding liver parenchyma for pathologic verification of the layers. We performed 60 LALRs and 39 robotic anatomical liver resections (RALRs) using an extrahepatic Glissonean approach, from April 2020 to April 2023, and verified the layers of the specimens removed during LALR and RALR based on pathologic examination. In addition, the surgical outcomes of LALR and RALR were compared. Results: Histologic examination facilitated by Elastica van Gieson staining revealed the presence of Laennec's capsule covering the liver parenchyma in a cadaveric model. Similar findings were obtained following LALR and RALR, thus confirming that the gap between the Glissonean pedicle and the Laennec's capsule can be dissected without injury to the parenchyma. The mean GPI time was 32.9 and 27.2 min in LALR and RALR, respectively. The mean blood loss was 289.7 and 131.6 mL in LALR and RALR, respectively. There was no significant difference in the incidence of Clavien-Dindo grade ≥III complications between the two groups. Conclusions: Laennec's capsule is the most important anatomical landmark in performing a safe and successful extrahepatic GPI. Based on this concept, it is possible for LALR and RALR to develop GPI focusing on the Laennec's capsule. Furthermore, a robotic system has the potential to increase the safety and decrease the difficulty of this challenging procedure.

ARR-GCN: Anatomy-Relation Reasoning Graph Convolutional Network for Automatic Fine-Grained Segmentation of Organ's Surgical Anatomy

Anatomical resection (AR) based on anatomical sub-regions is a promising method of precise surgical resection, which has been proven to improve long-term survival by reducing local recurrence. The fine-grained segmentation of an organ's surgical anatomy (FGS-OSA), i.e., segmenting an organ into multiple anatomic regions, is critical for localizing tumors in AR surgical planning. However, automatically obtaining FGS-OSA results in computer-aided methods faces the challenges of appearance ambiguities among sub-regions (i.e., inter-sub-region appearance ambiguities) caused by similar HU distributions in different sub-regions of an organ's surgical anatomy, invisible boundaries, and similarities between anatomical landmarks and other anatomical information. In this paper, we propose a novel fine-grained segmentation framework termed the "anatomic relation reasoning graph convolutional network" (ARR-GCN), which incorporates prior anatomic relations into the framework learning. In ARR-GCN, a graph is constructed based on the sub-regions to model the class and their relations. Further, to obtain discriminative initial node representations of graph space, a sub-region center module is designed. Most importantly, to explicitly learn the anatomic relations, the prior anatomic-relations among the sub-regions are encoded in the form of an adjacency matrix and embedded into the intermediate node representations to guide framework learning. The ARR-GCN was validated on two FGS-OSA tasks: i) liver segments segmentation, and ii) lung lobes segmentation. Experimental results on both tasks outperformed other state-of-the-art segmentation methods and yielded promising performances by ARR-GCN for suppressing ambiguities among sub-regions.

Augmented reality in liver surgery

INTRODUCTION

During an operation, augmented reality (AR) enables surgeons to enrich their vision of the operating field by means of digital imagery, particularly as regards tumors and anatomical structures. While in some specialties, this type of technology is routinely ustilized, in liver surgery due to the complexity of modeling organ deformities in real time, its applications remain limited. At present, numerous teams are attempting to find a solution applicable to current practice, the objective being to overcome difficulties of intraoperative navigation in an opaque organ.

OBJECTIVE

To identify, itemize and analyze series reporting AR techniques tested in liver surgery, the objectives being to establish a state of the art and to provide indications of perspectives for the future.

METHODS

In compliance with the PRISMA guidelines and availing ourselves of the PubMed, Embase and Cochrane databases, we identified English-language articles published between January 2020 and January 2022 corresponding to the following keywords: augmented reality, hepatic surgery, liver and hepatectomy.

RESULTS

Initially, 102 titles, studies and summaries were preselected. Twenty-eight corresponding to the inclusion criteria were included, reporting on 183patients operated with the help of AR by laparotomy (n=31) or laparoscopy (n=152). Several techniques of acquisition and visualization were reported. Anatomical precision was the main assessment criterion in 19 articles, with values ranging from 3mm to 14mm, followed by time of acquisition and clinical feasibility.

CONCLUSION

While several AR technologies are presently being developed, due to insufficient anatomical precision their clinical applications have remained limited. That much said, numerous teams are currently working toward their optimization, and it is highly likely that in the short term, the application of AR in liver surgery will have become more frequent and effective. As for its clinical impact, notably in oncology, it remains to be assessed.

Lesion or Pseudolesion? A Comprehensive Description of Perfusion-Based Liver Alterations on Contrast-Enhanced Computed Tomography and Literature Review

ABSTRACT

Pseudolesions on contrast-enhanced computed tomography represent a diagnostic challenge for radiologists because they could be difficult to distinguish from true space-occupying lesions. This article aims to provide a detailed overview of these entities based on radiological criteria (hyperattenuation or hypoattenuation, localization, morphology), as well as a brief review of the hepatic vascular anatomy and pathophysiological process. Relevant examples from hospital case series are reported as helpful hints to assist radiologists in recognizing and correctly diagnosing these abnormalities.

Automated Three-Dimensional Liver Reconstruction with Artificial Intelligence for Virtual Hepatectomy

OBJECTIVE

To validate the newly developed artificial intelligence (AI)-assisted simulation by evaluating the speed of three-dimensional (3D) reconstruction and accuracy of segmental volumetry among patients with liver tumors.

BACKGROUND

AI with a deep learning algorithm based on healthy liver computer tomography images has been developed to assist three-dimensional liver reconstruction in virtual hepatectomy.

METHODS

3D reconstruction using hepatic computed tomography scans of 144 patients with liver tumors was performed using two different versions of Synapse 3D (Fujifilm, Tokyo, Japan): the manual method based on the tracking algorithm and the AI-assisted method. Processing time to 3D reconstruction and volumetry of whole liver, tumor-containing and tumor-free segments were compared.

RESULTS

The median total liver volume and the volume ratio of a tumor-containing and a tumor-free segment were calculated as 1035 mL, 9.4%, and 9.8% by the AI-assisted reconstruction, whereas 1120 mL, 9.9%, and 9.3% by the manual reconstruction method. The mean absolute deviations were 16.7 mL and 1.0% in the tumor-containing segment and 15.5 mL and 1.0% in the tumor-free segment. The processing time was shorter in the AI-assisted (2.1 vs. 35.0 min; p < 0.001).

CONCLUSIONS

The virtual hepatectomy, including functional liver volumetric analysis, using the 3D liver models reconstructed by the AI-assisted methods, was reliable for the practical planning of liver tumor resections.

Tumors located in the central column of the liver are associated with increased surgical difficulty and postoperative complications following open liver resection for colorectal metastases

BACKGROUND

To assess the impact of difficult location (based on preoperative computed tomography) of liver metastases from colorectal cancer (LMCRC) on surgical difficulty, and occurrence of severe postoperative complications (POCs).

METHODS

A retrospective single-centre study of 911 consecutive patients with LMCRC who underwent hepatectomy by the open approach between 1998 and 2011, before implementation of laparoscopic surgery to obviate approach selection bias. LMCRC with at least one of the following four features on preoperative imaging: tumor invading the hepatocaval confluence or retro-hepatic inferior vena cava, centrally located (Segments 4,5,8) and >10 cm in diameter, abutting the supra-hilar area, or involving the paracaval portion or caudate process of Segment 1; were considered as topographically difficult (top-diff). Independent predictors of surgical difficulty assessed by number of blood units transfused, duration of ischemia, and number of sessions of pedicle clamping during surgery and of severe POCs were identified by multivariate analysis before, and after propensity score matching.

RESULTS

Top-diff tumor location independently predicted surgical difficulty. Severe POCs were associated with the tumor location [top-diff vs. topographically non difficult (non top-diff)], preoperative portal vein embolization, and variables related to surgical difficulty.

CONCLUSION

LMCRC in difficult location independently predicts surgical difficulty and severe POCs.

Radioembolization Dosimetry with Total-Body 90Y PET

Transarterial radioembolization (TARE) is a locoregional radiopharmaceutical therapy based on the delivery of radioactive ⁹⁰Y microspheres to liver tumors. The importance of personalized dosimetry to make TARE safer and more effective has been demonstrated in recent clinical studies, stressing the need for quantification of the dose-response relationship to ultimately optimize the administered activity before treatment and image it after treatment. ⁹⁰Y dosimetric studies are challenging because of the lack of accurate and precise methods but are best realized with PET combined with Monte Carlo simulations and other image modalities to calculate a segmental dose distribution. The aim of this study was to assess the suitability of imaging ⁹⁰Y PET patients with the total-body PET/CT uEXPLORER and to investigate possible improvements in TARE ⁹⁰Y PET-based dosimetry. The uEXPLORER is the first commercially available ultra-high-resolution (171 cps/kBq) total-body digital PET/CT device with a 194-cm axial PET field of view that enables the whole body to be scanned at a single bed position. Methods: Two PET/CT scanners were evaluated in this study: the Biograph mCT and the total-body uEXPLORER. Images of a National Electrical Manufacturers Association (NEMA) image-quality phantom and 2 patients were reconstructed using our standard clinical oncology protocol. A late portal phase contrast-enhanced CT scan was used to contour the liver segments and create corresponding volumes of interest. To calculate the absorbed dose, Monte Carlo simulations were performed using Geant4 Application for Tomographic Emission (GATE). The absorbed dose and dose-volume histograms were calculated for all 6 spheres (diameters ranging from 10 to 37 mm) of the NEMA phantom, the liver segments, and the entire liver. Differences between the phantom doses and an analytic ground truth were quantified through the root mean squared error. Results: The uEXPLORER showed a higher signal-to-noise ratio at 10- and 13-mm diameters, consistent with its high spatial resolution and system sensitivity. The total liver-absorbed dose showed excellent agreement between the uEXPLORER and the mCT for both patients, with differences lower than 0.2%. Larger differences of up to 60% were observed when comparing the liver segment doses. All dose-volume histograms were in good agreement, with narrower tails for the uEXPLORER in all segments, indicating lower image noise. Conclusion: This patient study is compelling for the use of total-body ⁹⁰Y PET for liver dosimetry. The uEXPLORER scanner showed a better signal-to-noise ratio than mCT, especially in lower-count regions of interest, which is expected to improve dose quantification and tumor dosimetry.

The potential of organoids in toxicologic pathology: role of toxicologic pathologists in in vitro chemical hepatotoxicity assessment

The development of in vitro toxicity assessment methods using cultured cells has gained popularity for promoting animal welfare in animal experiments. Herein, we briefly discuss the current status of hepatoxicity assessment using human- and rat-derived hepatocytes; we focus on the liver organoid method, which has been extensively studied in recent years, and discuss how toxicologic pathologists can use their knowledge and experience to contribute to the development of in vitro chemical hepatotoxicity assessment methods for drugs, pesticides, and chemicals. We also propose how toxicological pathologists should assess toxicity regarding the putative distribution of undifferentiated and differentiated cells in the organoid when liver organoids are observed in hematoxylin and eosin-stained specimens. This was done while considering the usefulness and limitations of in vitro studies for toxicologic pathology assessment.

Patient-individualized resection planning in liver surgery using 3D print and virtual reality (i-LiVR)-a study protocol for a prospective randomized controlled trial

Background

A multitude of different diseases—benign and malign—can require surgery of the liver. The liver is an especially challenging organ for resection planning due to its unique and interindividually variable anatomy. This demands a high amount of mental imagination from the surgeon in order to plan accordingly - a skill, which takes years of training to acquire and which is difficult to teach. Since the volume of the functional remnant liver is of great importance, parenchyma sparing resections are favoured. 3D reconstructions of computed tomography imaging enable a more precise understanding of anatomy and facilitate resection planning. The modality of presentation of these 3D models ranges from 2D monitors to 3D prints and virtual reality applications.

Methods

The presented trial compares three different modes of demonstration of a 3D reconstruction of CT scans of the liver, which are 3D print, a demonstration on a regular computer screen or using a head-mounted virtual reality headset, with the current gold standard of viewing the CT scan on a computer screen. The group size was calculated with n=25 each. Patients with major liver resections in a laparoscopic or open fashion are eligible for inclusion. Main endpoint is the comparison of the quotient between planned resection volume and actual resection volume between these groups. Secondary endpoints include usability for the surgical team as well as patient specifics and perioperative outcome measures and teaching issues.

Discussion

The described study will give insight in systematic planning of liver resections and the comparison of different demonstration modalities of 3D reconstruction of preoperative CT scans and the preference of technology. Especially teaching of these demanding operations is underrepresented in prior investigations.

Trial registration

Prospective trials registration at the German Clinical Trials register with the registration number DRKS00027865. Registration Date: January 24, 2022.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06347-0.

Liver Surgery: Important Considerations for Pre- and Postoperative Imaging

Liver surgery may be a curative treatment option not only for primary liver neoplasms but also for liver metastases in selected patients. The number of liver surgeries performed worldwide has increased, but surgical morbidity associated with these surgeries remains significant. Therefore, radiologists need to understand the terminology, surgical techniques, resectability and unresectability criteria, and possible postoperative complications as these are part of the decision-making process. Because vascular and biliary variations are common, an adequate preoperative anatomic evaluation determines the best surgical technique, helps identify patients in whom additional surgical steps will be required, and reduces the risk of inadvertent injury. The surgeon must ensure that the future liver remnant is sufficient to maintain adequate function, aided by the radiologist who can provide valuable information such as the presence of steatosis, biliary dilatation, signs of cirrhosis, and portal hypertension, in addition to the volume of the future liver remnant. Postoperative complications must also be understood and evaluated. The most common postoperative complications are vascular (bleeding, thrombosis, and ischemia), biliary (fistulas, bilomas, and strictures), infectious (incisional or deep), those related to liver failure, and even tumor recurrence. An invited commentary by Winslow is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Weakly Supervised Liver Tumor Segmentation Using Couinaud Segment Annotation

Automatic liver tumor segmentation is of great importance for assisting doctors in liver cancer diagnosis and treatment planning. Recently, deep learning approaches trained with pixel-level annotations have contributed many breakthroughs in image segmentation. However, acquiring such accurate dense annotations is time-consuming and labor-intensive, which limits the performance of deep neural networks for medical image segmentation. We note that Couinaud segment is widely used by radiologists when recording liver cancer-related findings in the reports, since it is well-suited for describing the localization of tumors. In this paper, we propose a novel approach to train convolutional networks for liver tumor segmentation using Couinaud segment annotations. Couinaud segment annotations are image-level labels with values ranging from 1 to 8, indicating a specific region of the liver. Our proposed model, namely CouinaudNet, can estimate pseudo tumor masks from the Couinaud segment annotations as pixel-wise supervision for training a fully supervised tumor segmentation model, and it is composed of two components: 1) an inpainting network with Couinaud segment masks which can effectively remove tumors for pathological images by filling the tumor regions with plausible healthy-looking intensities; 2) a difference spotting network for segmenting the tumors, which is trained with healthy-pathological pairs generated by an effective tumor synthesis strategy. The proposed method is extensively evaluated on two liver tumor segmentation datasets. The experimental results demonstrate that our method can achieve competitive performance compared to the fully supervised counterpart and the state-of-the-art methods while requiring significantly less annotation effort.

Can the presence of KRAS mutations guide the type of liver resection during simultaneous resection of colorectal liver metastasis?

Backgrounds/Aims

It is generally accepted that non-anatomical resection (NAR) in colorectal liver metastasis (CRLM) has comparable safety and efficacy compared to anatomical resection (AR); however, there are reports that AR may have better outcomes in KRAS mutated CRLM. This study aimed to determine the effects of KRAS mutations and surgical techniques on survival outcomes in CRLM patients.

Methods

Two hundred fifty patients who underwent hepatic resection of CRLM with known KRAS mutational status between 2007 and 2018 were analyzed. A total of 94 KRAS mutated CRLM and 156 KRAS wild-type CRLM were subdivided by surgical approach and compared for short- and long-term outcomes.

Results

In both KRAS wild-type and mutated type, there was no difference in estimated blood loss, postoperative complications, and 30-day mortality. There was no difference in disease-free survival (DFS) between AR and NAR in both groups (p = 0.326, p = 0.954, respectively). Finally, there was no difference in intrahepatic DFS between AR and NAR groups in both the KRAS groups (p = 0.165, p = 0.516, respectively).

Conclusions

The presence of KRAS mutation may not be a significant factor when deciding the approach in simultaneous resection of CRLM.

Laparoscopic anatomical liver resection for malignancies using positive or negative staining technique with intraoperative indocyanine green-fluorescence imaging

BACKGROUND

Indications for a minimally invasive resections are increasing worldwide, but respecting anatomical planes during intraparenchymal transection is demanding. Intraoperative ICG fluorescence staining of liver parenchyma has been introduced as a tool for real-time intraoperative guidance. The aim of this study is to make a systematic review of the current relevant literature on indications, techniques, and results of laparoscopic anatomical liver resection (LALR) using intraoperative indocyanine green (ICG) fluorescence for positive and negative staining of liver segments in patients affected by liver malignancies.

METHODS

Electronic bibliographical databases (MEDLINE and PubMed) were searched according to the PRISMA criteria. English language articles meeting the selection criteria and published until June 2020 were retrieved and reviewed.

RESULTS

a total of 86 articles were initially found and 11 articles were finally included in the analysis with a total of 83 patients treated. Sixty-two patients (74.6%) underwent mono-segmentectomies. Thirty-five patients (42.1%) underwent the positive staining technique, and forty-eight patients (57.8%) the negative staining technique.

CONCLUSIONS

The positive or negative indocyanine green staining technique with real-time fluorescence guidance is an emerging and promising approach. However, the technique has to be standardized and advantages in terms of oncologic results still need validation in further studies.

Hybrid Additive Fabrication of a Transparent Liver with Biosimilar Haptic Response for Preoperative Planning

Due to the complexity of liver surgery, the interest in 3D printing is constantly increasing among hepatobiliary surgeons. The aim of this study was to produce a patient-specific transparent life-sized liver model with tissue-like haptic properties by combining additive manufacturing and 3D moulding. A multistep pipeline was adopted to obtain accurate 3D printable models. Semiautomatic segmentation and registration of routine medical imaging using 3D Slicer software allowed to obtain digital objects representing the structures of interest (liver parenchyma, vasculo-biliary branching, and intrahepatic lesion). The virtual models were used as the source data for a hybrid fabrication process based on additive manufacturing using soft resins and casting of tissue-mimicking silicone-based blend into 3D moulds. The model of the haptic liver reproduced with high fidelity the vasculo-biliary branching and the relationship with the intrahepatic lesion embedded into the transparent parenchyma. It offered high-quality haptic perception and a remarkable degree of surgical and anatomical information. Our 3D transparent model with haptic properties can help surgeons understand the spatial changes of intrahepatic structures during surgical manoeuvres, optimising preoperative surgical planning.

Ligation Method to Specifically Label a Liver Segment With Indocyanine Green in an Orthotopic Nude-Mouse Liver-Metastasis Model

BACKGROUND/AIM

The visualization of hepatic segments with indocyanine green (ICG) fluorescence can aid in anatomic liver resection. The present study aimed to develop a method to specifically label an hepatic segment in a nude mouse model with liver metastasis.

MATERIALS AND METHODS

An orthotopic mouse model was established by surgical orthotopic implantation (SOI) of a patient-derived colon-cancer liver metastasis in the left lobe of the liver. Three weeks after SOI, the left Glissonean pedicle was ligated and 10 μg ICG was administrated intravenously. Images were obtained with the Pearl Trilogy Imaging System.

RESULTS

All mice expressed an 800 nm signal from ICG on the right lobe of the liver. The left lobe of the liver, in which the tumor was located, showed no fluorescence and had ischemia due to successful ligation of the Glissonean pedicle.

CONCLUSION

The ligation of the Glissonean pedicle enables specific liver-segment labeling with ICG, which has potential clinical application for liver metastasectomy.

Augmented Reality during Open Liver Surgery Using a Markerless Non-rigid Registration System

INTRODUCTION

Intraoperative navigation during liver resection remains difficult and requires high radiologic skills because liver anatomy is complex and patient-specific. Augmented reality (AR) during open liver surgery could be helpful to guide hepatectomies and optimize resection margins but faces many challenges when large parenchymal deformations take place. We aimed to experiment a new vision-based AR to assess its clinical feasibility and anatomical accuracy.

PATIENTS AND METHODS

Based on preoperative CT scan 3-D segmentations, we applied a non-rigid registration method, integrating a physics-based elastic model of the liver, computed in real time using an efficient finite element method. To fit the actual deformations, the model was driven by data provided by a single RGB-D camera. Five livers were considered in this experiment. In vivo AR was performed during hepatectomy (n = 4), with manual handling of the livers resulting in large realistic deformations. Ex vivo experiment (n = 1) consisted in repeated CT scans of explanted whole organ carrying internal metallic landmarks, in fixed deformations, and allowed us to analyze our estimated deformations and quantify spatial errors.

RESULTS

In vivo AR tests were successfully achieved in all patients with a fast and agile setup installation (< 10 min) and real-time overlay of the virtual anatomy onto the surgical field displayed on an external screen. In addition, an ex vivo quantification demonstrated a 7.9 mm root mean square error for the registration of internal landmarks.

CONCLUSION

These first experiments of a markerless AR provided promising results, requiring very little equipment and setup time, yet providing real-time AR with satisfactory 3D accuracy. These results must be confirmed in a larger prospective study to definitively assess the impact of such minimally invasive technology on pathological margins and oncological outcomes.

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.

Fluorescence-guided fiber-optic micronavigation using microscopic identification of vascular boundary of liver segment and tumors

Background: The exact identification of tumor boundaries and related liver segments is especially important for liver tumor surgery. This study aimed to evaluate a new approach for vascular boundary assessment and surgical navigation based on fiber-optic microscopy and microvascular fluorescence labeling.

Methods: Antibody clones with fast binding ability were identified and selected using immunofluorescence. We evaluated the endothelial capture efficacy for an anti-mouse CD31 antibody labeled with different fluorophores and different degrees of labeling ex vivo. Segment boundary identification and navigation potential using endothelial capture were explored by two different fiber-optic microscopy systems. Finally, microvasculature labeling and fiber-optic microscopy were used to identify and treat microscopic liver tumors in vivo.

Results: The following monoclonal antibodies were selected: anti-mouse CD31 (clone 390), anti-mouse CD54 (YN1/1.7.4), anti-human CD31 (WM59), and anti-human CD54 (HA58). These clones showed fast binding to endothelial cells and had long half-lives. The fluorophore choice and the degree of antibody labeling did not significantly affect capture efficacy in an isolated liver perfusion model. The microvascular system was clearly identified with wide-field fiber-optic microscopy after labeling the endothelium with low doses of specific antibodies, and the specifically labeled liver segment could be microscopically dissected. High antibody doses were required for confocal laser endomicroscopy. After microscopically identifying the vascular margin in vivo, tumor thermoablation strongly reduced tumor size or totally eliminated tumors.

Conclusions: We demonstrated that vascular boundaries of liver tumors and locally perfused liver segments were accurately identified and surgical micronavigation was facilitated with fiber-optic microscopy and selected endothelium-specific antibodies.

A universal mathematical model applied to the congenital ventral penile curvature

INTRODUCTION

The macroscopic dynamic of fetal penis development presents a pattern resembling the unfolding of a spiral, so congenital ventral penile curvature could indicate that this natural sequence has been interrupted. Our aim in this article is to offer a mathematical model of congenital ventral curvature of the penis.

MATERIALS AND METHODS

Five individuals who presented with congenital ventral penile curvature and three who presented with acquired penile ventral curvature due to Peyronie's disease were evaluated. The penises were photographed during an induced erection test and the penile curvature patterns were compared with an equiangular spiral. When an association was found, a potential relationship to the golden spiral-a type of equiangular spiral-was also assessed. The mathematical spiral relationships were analyzed using Wolfram CDF Player® (Logarithmic Spiral) and PhiMatrix® software. The Wolfram software generated logarithmic spirals equivalent to the penile curvature with appropriate mathematical values. The PhiMatrix software, which builds any golden spirals from golden rectangles, was used to check whether the spiral was golden as well as equiangular.

RESULTS

An equiangular spiral that was also golden was found in all cases of congenital ventral penile curvature. In contrast, none of the acquired penile ventral curvature cases showed a specific pattern.

CONCLUSION

Congenital ventral penile curvature has the mathematical pattern of a golden spiral. Our results offer a mathematical algorithm for potential use in surgical reconstruction procedures, regenerative medicine, tissue engineering, robotics, and body-machine interfaces.

Considerations for Using the Vasculature as a Coordinate System to Map All the Cells in the Human Body

Several ongoing international efforts are developing methods of localizing single cells within organs or mapping the entire human body at the single cell level, including the Chan Zuckerberg Initiative's Human Cell Atlas (HCA), and the Knut and Allice Wallenberg Foundation's Human Protein Atlas (HPA), and the National Institutes of Health's Human BioMolecular Atlas Program (HuBMAP). Their goals are to understand cell specialization, interactions, spatial organization in their natural context, and ultimately the function of every cell within the body. In the same way that the Human Genome Project had to assemble sequence data from different people to construct a complete sequence, multiple centers around the world are collecting tissue specimens from diverse populations that vary in age, race, sex, and body size. A challenge will be combining these heterogeneous tissue samples into a 3D reference map that will enable multiscale, multidimensional Google Maps-like exploration of the human body. Key to making alignment of tissue samples work is identifying and using a coordinate system called a Common Coordinate Framework (CCF), which defines the positions, or "addresses," in a reference body, from whole organs down to functional tissue units and individual cells. In this perspective, we examine the concept of a CCF based on the vasculature and describe why it would be an attractive choice for mapping the human body.

Laennec's approach for laparoscopic anatomic hepatectomy based on Laennec's capsule

BACKGROUND

Although isolating Glissonean pedicles and hepatic veins are critical procedures during anatomical hepatectomy, there is no standardized approach. We propose the novel Laennec's approach for laparoscopic anatomic hepatectomy (LAH) based on Laennec's capsule, which serves as the anatomic landmark for LAH. The aim of this study was to elucidate that the natural gap between Laennec's capsule and the adjacent tissues contributes to standardization of the surgical technique for LAH.

METHODS

Eighty-four cases were enrolled in this observable clinical trial. They underwent LAH for liver diseases. Laennec's approach was proposed for LAH based on Laennec's capsule. The liver tissues close to Glissonean pedicle, hepatic veins, naked area, and inferior vena cava were collected for hematoxylin and eosin, resorcinol-fuchsin staining, and immunohistochemistry.

RESULTS

The staining revealed capsule packaging of the whole liver independent of the adjacent tissues and intrahepatic vessels. A natural gap was found between Laennec's capsule and the adjacent tissues at different sites. Laennec's capsule served as the landmark for isolating Glissonean pedicle and hepatic veins, mobilizing the liver, and performing Hanging maneuver. Eighty-four cases underwent LAH for liver diseases using this strategy. The operation time was 277.23 min. The mean of hospital days was 9.8.

CONCLUSIONS

Laennec's approach based on Laennec's capsule contributes to standardization of the surgical technique for LAH, and brings innovations that facilitates safe and effective liver resection under laparoscopy.

[Role of the radiologist in surgery of colorectal liver metastases : What should be removed and what must remain]

BACKGROUND

The radical resection of colorectal liver metastases is the only curative option for affected patients. If properly performed, surgery provides the chance of long-term tumor-free survival.

OBJECTIVE

Summary of the critical interaction points between radiology and surgery in the planning and performance of (complex) liver resections.

RESULTS

There are many interaction points between radiology and surgery in the treatment of patients with colorectal liver metastases. Radiology supports surgery by providing detailed information of the localization of metastases, information on liver inflow and outflow as well as basic information on liver quality and function. Perioperatively, it provides interventional treatment options for postoperative complications as well as ablation of non-resectable metastases.

CONCLUSION

Complex liver resections can only be performed properly and successfully after thorough planning by an interdisciplinary board of surgeons, radiologists and associated disciplines.

A novel method to determine hepatic segments using Sonazoid, an ultrasound contrast agent

The conventional radiologic method for liver segmentation is based on the position of the hepatic and portal veins. However, during surgery, liver segments are resected based on the distribution of hepatic portal blood flow. This discrepancy can lead to a number of problems, such as miscommunication among clinicians, missing the location of the segment with the hepatic mass, and the risk of extended hepatic resection. We suggest a novel method to determine hepatic segments based on portal blood flow, as in the surgical approach, but by using high and low mechanical indexes in contrast-enhanced ultrasonography with Sonazoid. This approach is helpful for preoperatively determining hepatic segments and reducing the risk of missing the location of a hepatic tumor or extended hepatic resection.

Rubber tourniquet technique: A simple, safe, and cost-effective method of hepatic resection in neonates and infants

BACKGROUND

Despite the improvements in patient care, understanding of surgical anatomy of liver and surgical techniques, liver resection is a high-risk procedure specifically in infants and neonates; whose blood volume is limited (80 ml/kg). This report shares the experience of hepatic resection with "Rubber tourniquet technique" in patients less than 6-months of age.

METHODS

Hepatic resection in a 4-month-old pair of Conjoined twins with shared liver and a 3-day old baby with large Congenital Hepatoblastoma was performed using Penrose rubber drain as a tourniquet around the liver parenchyma to reduce blood loss.

RESULTS

Blood loss was minimal (<20CC) and all the three babies survived the procedure without complications.

CONCLUSION

Rubber tourniquet technique is simple, safe and cost-effective for liver resections in neonates and infants with hepatic lesions and separation of conjoined twins with shared liver and it can easily be employed in resource constraint settings.

Liver segment imaging using monocyte sequestration: a potential tool for fluorescence-guided liver surgery

Background: The accurate determination of liver segment anatomy is essential to perform liver resection without complications and to ensure long-term outcomes after this operation. There are several perioperative methods for segment identification and surgical navigation, such as intraoperative ultrasound, indigo carmine and near-infrared imaging with indocyanine green. The present study experimentally analyzed the usefulness of monocyte sequestration for liver segment labeling and imaging.

Methods: Human monocytes were isolated from peripheral blood and directly or indirectly labeled with calcein or IRDye 800CW. Potential toxicity, labeling stability, and adhesion to ICAM-1 were analyzed in vitro. Monocyte sequestration in the liver microvasculature and liver segment labeling and boundary demarcation were studied using isolated mouse and pig liver perfusion and via intraportal injection in mouse liver tumor models.

Results: The highest monocyte labeling efficiency was achieved using direct labeling with IRDye 800CW. Labeling was stable and did not influence cell viability. The labeled monocytes were highly sequestrated in the liver microvasculature, both after ex vivo perfusion and after injection in vivo , resulting in excellent labeling of selected liver segments and strong segment boundary demarcation. In contrast to results to a normal liver, monocyte sequestration was very low in tumor-associated blood vessels.

Conclusions: The present experimental study shows that sequestration of labeled monocytes after superselective application demarcates the selected liver segment. These results illustrate potential of this technique for surgical navigation during liver surgery.

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

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

2017 PRETEXT: radiologic staging system for primary hepatic malignancies of childhood revised for the Paediatric Hepatic International Tumour Trial (PHITT)

Imaging is crucial in the assessment of children with a primary hepatic malignancy. Since its inception in 1992, the PRETEXT (PRE-Treatment EXTent of tumor) system has become the primary method of risk stratification for hepatoblastoma and pediatric hepatocellular carcinoma in numerous cooperative group trials across the world. The PRETEXT system is made of two components: the PRETEXT group and the annotation factors. The PRETEXT group describes the extent of tumor within the liver while the annotation factors help to describe associated features such as vascular involvement (either portal vein or hepatic vein/inferior vena cava), extrahepatic disease, multifocality, tumor rupture and metastatic disease (to both the lungs and lymph nodes). This manuscript is written by members of the Children's Oncology Group (COG) in North America, the International Childhood Liver Tumors Strategy Group (SIOPEL) in Europe, and the Japanese Study Group for Pediatric Liver Tumor (JPLT; now part of the Japan Children's Cancer Group) and represents an international consensus update to the 2005 PRETEXT definitions. These definitions will be used in the forthcoming Trial to Pediatric Hepatic International Tumor Trial (PHITT).

3D microfluidic liver cultures as a physiological preclinical tool for hepatitis B virus infection

With more than 240 million people infected, hepatitis B virus (HBV) is a major health concern. The inability to mimic the complexity of the liver using cell lines and regular primary human hepatocyte (PHH) cultures pose significant limitations for studying host/pathogen interactions. Here, we describe a 3D microfluidic PHH system permissive to HBV infection, which can be maintained for at least 40 days. This system enables the recapitulation of all steps of the HBV life cycle, including the replication of patient-derived HBV and the maintenance of HBV cccDNA. We show that innate immune and cytokine responses following infection with HBV mimic those observed in HBV-infected patients, thus allowing the dissection of pathways important for immune evasion and validation of biomarkers. Additionally, we demonstrate that the co-culture of PHH with other non-parenchymal cells enables the identification of the cellular origin of immune effectors, thus providing a valuable preclinical platform for HBV research.

The Effect of Three-Dimensional Preoperative Simulation on Liver Surgery

Background

In the past decade, three-dimensional (3D) simulation has been commonly used for liver surgery. However, few studies have analyzed the usefulness of this 3D simulation. The aim of this study was to evaluate the effect of 3D simulation on the outcome of liver surgery.

Methods

We retrospectively analyzed 240 consecutive patients who underwent liver resection. The patients were divided into two groups: those who received 3D preoperative simulation (“3D group”, n = 120) and those who did not undergo 3D preoperative simulation (“without 3D group”, n = 120). The perioperative outcomes, including operation time, blood loss, maximum aspartate transaminase level, length of postoperative stay, postoperative complications and postoperative mortality, were compared between the two groups. The predicted resected liver volume was compared with the actual resected volume.

Results

The median operation time for the 3D group was 36 min shorter than that for the without 3D group (P = 0.048). There were no significant differences in other outcomes between the two groups. A subgroup analysis revealed that the operation time of repeated hepatectomy and segmentectomy for the 3D group was shorter than that for the without 3D group (P = 0.03). There was a strong correlation between the predicted liver volume and the actual resected liver weight (r = 0.80, P < 0.001).

Conclusion

These findings demonstrate that 3D preoperative simulation may reduce the operation time, particularly for repeated hepatectomy and segmentectomy.

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.

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.

Robotic versus open liver resections: A case-matched comparison

BACKGROUND

Most hepatic resections are currently performed using an open approach. Robotic surgery might enable the transition of these procedures to minimally invasive surgery.

METHODS

Pre-, peri- and post-operative data of all patients who underwent a liver resection from 2009/2012 to 2001/2015, were collected prospectively. All robotic resection patients were matched 1:1 to patients who underwent open surgery. Pre- and perioperative data, up to 30 days, were analyzed.

RESULTS

Sixteen robotic and open hepatic resections were identified. Fewer complication events and shorter lengths of stay (LOS, 7.9 versus 11 days, P = 0.0603) were observed for robotic resections. Length of stay in the intermediate care unit (IMC) was shorter after the robotic procedure (10 h vs 16.6 h, P = 0.0699). Operating room (OR) time was significantly longer in the robotic resection cohort (352.8 vs 239.6 min, P = 0.0215). All tumor margins were negative.

CONCLUSIONS

This preliminary comparison demonstrates the general feasibility of minor robotic liver resection in selected cases.

Computer-assisted surgery planning in children with complex liver tumors identifies variability of the classical Couinaud classification

BACKGROUND

In complex malignant pediatric liver tumors there is an ongoing discussion regarding surgical strategy; for example, primary organ transplantation versus extended resection in hepatoblastoma involving 3 or 4 sectors of the liver. We evaluated the possible role of computer-assisted surgery planning in children with complex hepatic tumors.

METHODS

Between May 2004 and March 2016, 24 Children with complex liver tumors underwent standard multislice helical CT scan or MRI scan at our institution. Imaging data were processed using the software assistant LiverAnalyzer (Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany). Results were provided as Portable Document Format (PDF) with embedded interactive 3-dimensional surface mesh models.

RESULTS

Median age of patients was 33months. Diagnoses were hepatoblastoma (n=14), sarcoma (n=3), benign parenchyma alteration (n=2), as well as hepatocellular carcinoma, rhabdoid tumor, focal nodular hyperplasia, hemangioendothelioma, or multiple hepatic metastases of a pancreas carcinoma (each n=1). Volumetry of liver segments identified remarkable variations and substantial aberrances from the Couinaud classification. Computer-assisted surgery planning was used to determine surgical strategies in 20/24 children; this was especially relevant in tumors affecting 3 or 4 liver sectors. Primary liver transplantation could be avoided in 12 of 14 hepaoblastoma patients who theoretically were candidates for this approach.

CONCLUSIONS

Computer-assisted surgery planning substantially contributed to the decision for surgical strategies in children with complex hepatic tumors. This tool possibly allows determination of specific surgical procedures such as extended surgical resection instead of primary transplantation in certain conditions.

Management of patients with colorectal liver metastasis in eleven questions and answers

INTRODUCTION

Colorectal liver metastasis (CRLM) is the most frequent indication for liver resection in many centers. Recent improvements in oncology, surgery, interventional radiology, pathology and anesthesiology allow curative treatment in a larger proportion of patients with CRLM. Areas covered: We illustrate the various aspects of the management of CRLM through 11 questions that summarize the topic, from the current obtained survival to future perspectives such as transplantation. The limits of a curative treatment are also presented from different angles, such as the benefits of pathology, the surgical options for extreme resections, the available chemotherapies and their efficacy, or the non-surgical ablative treatments. Expert commentary: Given the increasing therapeutic possibilities, we strengthen the importance to analyze the situation of each patient with CRLM in a dedicated multidisciplinary team, in order to offer the best individualized treatment combination.

[Vascular management in anatomical liver resection]

The vascular management in anatomical liver resection plays a pivotal role in maintaining an adequately functional residual liver volume. In this respect it is essential to guarantee an adequate portal and arterial inflow as well venous outflow for the whole residual liver (lobe or segments). To achieve this, the liver surgeon should have excellent perioperative imaging, surgical expertise based on knowledge of vascular anatomy, physiology and hemodynamics of the liver and a well-designed and cautious operative strategy. The use of intraoperative ultrasonography (with or without contrast enhancement) and modern parenchymal dissectors (e.g. ultrasound or water jet dissectors) are strongly recommended.