Machine learning in liver surgery: Benefits and pitfalls.

The application of machine learning (ML) algorithms in various fields of hepatology is an issue of interest. However, we must be cautious with the results. In this letter, based on a published ML prediction model for acute kidney injury after liver surgery, we discuss some limitations of ML models and how they may be addressed in the future. Although the future faces significant challenges, it also holds a great potential.

Results from the european survey on preoperative management and optimization protocols for PeriHilar cholangiocarcinoma.

BACKGROUND: Major surgery, along with preoperative cholestasis-related complications, are responsible for the increased risk of morbidity and mortality in perihilar cholangiocarcinoma (pCCA). The aim of the present survey is to provide a snapshot of current preoperative management and optimization strategies in Europe. METHODS: 61 European centers, experienced in hepato-biliary surgery completed a 59-questions survey regarding pCCA preoperative management. Centers were stratified according to surgical caseload (<5 and ≥ 5 cases/year) and preoperative management protocols' application. RESULTS: The overall case volume consisted of 6333 patients. Multidisciplinary discussion was routinely performed in 91.8% of centers. Most respondents (96.7%) recognized the importance of a well-structured preoperative protocol. The preferred method for biliary drainage was percutaneous transhepatic biliary drainage (60.7%) while portal vein embolization was the preferred technique for liver hypertrophy (90.2%). Differences in preoperative pathologic confirmation of malignancy (35.8% vs 28.7%; p < 0.001), number of mismanaged referred patients (88.2% vs 50.8%; p < 0.001), biliary drainage (65.1% vs 55.6%; p = 0.015) and liver function evaluation (37.2% vs 5.6%; p = 0.001) were found between centers according to groups' stratification. CONCLUSION: The importance of a correct preoperative management is recognized. Nevertheless, the current lack of guidelines leads to wide heterogeneity of behaviors among centers. This survey can provide recommendations to improve pCCA perioperative outcomes.

Machine perfusion and the prevention of ischemic type biliary lesions following liver transplant: What is the evidence?

The widespread uptake of different machine perfusion (MP) strategies for liver transplant has been driven by an effort to minimize graft injury. Damage to the cholangiocytes during the liver donation, preservation, or early posttransplant period may result in stricturing of the biliary tree and inadequate biliary drainage. This problem continues to trouble clinicians, and may have catastrophic consequences for the graft and patient. Ischemic injury, as a result of compromised hepatic artery flow, is a well-known cause of biliary strictures, sepsis, and graft failure. However, very similar lesions can appear with a patent hepatic artery and these are known as ischemic type biliary lesions (ITBL) that are attributed to microcirculatory dysfunction rather than main hepatic arterial compromise. Both the warm and cold ischemic period duration appear to influence the onset of ITBL. All of the commonly used MP techniques deliver oxygen to the graft cells, and therefore may minimize the cholangiocyte injury and subsequently reduce the incidence of ITBL. As clinical experience and published evidence grows for these modalities, the impact they have on ITBL rates is important to consider. In this review, the evidence for the three commonly used MP strategies (abdominal normothermic regional perfusion [A-NRP], hypothermic oxygenated perfusion [HOPE], and normothermic machine perfusion [NMP] for ITBL prevention has been critically reviewed. Inconsistencies with ITBL definitions used in trials, coupled with variations in techniques of MP, make interpretation challenging. Overall, the evidence suggests that both HOPE and A-NRP prevent ITBL in donated after circulatory death grafts compared to cold storage. The evidence for ITBL prevention in donor after brain death grafts with any MP technique is weak.

PRPF8 increases the aggressiveness of hepatocellular carcinoma by regulating FAK/AKT pathway via fibronectin 1 splicing.

Hepatocellular carcinoma (HCC) pathogenesis is associated with alterations in splicing machinery components (spliceosome and splicing factors) and aberrant expression of oncogenic splice variants. We aimed to analyze the expression and potential role of the spliceosome component PRPF8 (pre-mRNA processing factor 8) in HCC. PRPF8 expression (mRNA/protein) was analyzed in a retrospective cohort of HCC patients (n = 172 HCC and nontumor tissues) and validated in two in silico cohorts (TCGA and CPTAC). PRPF8 expression was silenced in liver cancer cell lines and in xenograft tumors to understand the functional and mechanistic consequences. In silico RNAseq and CLIPseq data were also analyzed. Our results indicate that PRPF8 is overexpressed in HCC and associated with increased tumor aggressiveness (patient survival, etc.), expression of HCC-related splice variants, and modulation of critical genes implicated in cancer-related pathways. PRPF8 silencing ameliorated aggressiveness in vitro and decreased tumor growth in vivo. Analysis of in silico CLIPseq data in HepG2 cells demonstrated that PRPF8 binds preferentially to exons of protein-coding genes, and RNAseq analysis showed that PRPF8 silencing alters splicing events in multiple genes. Integrated and in vitro analyses revealed that PRPF8 silencing modulates fibronectin (FN1) splicing, promoting the exclusion of exon 40.2, which is paramount for binding to integrins. Consistent with this finding, PRPF8 silencing reduced FAK/AKT phosphorylation and blunted stress fiber formation. Indeed, HepG2 and Hep3B cells exhibited a lower invasive capacity in membranes treated with conditioned medium from PRPF8-silenced cells compared to medium from scramble-treated cells. This study demonstrates that PRPF8 is overexpressed and associated with aggressiveness in HCC and plays important roles in hepatocarcinogenesis by altering FN1 splicing, FAK/AKT activation and stress fiber formation.

Are short-term complications associated with poor allograft and patient survival after liver transplantation? A systematic review of the literature and expert panel recommendations.

BACKGROUND: Maximizing patient and allograft survival after liver transplant (LT) is important from both a patient care and organ utilization perspective. Although individual studies have addressed the effects of short-term post-LT complications on a limited scale, there has not been a systematic review of the literature formally assessing the potential effects of early complications on long-term outcomes. OBJECTIVES: To identify whether short-term complications after LT affect allograft and overall survival, to identify short-term complications of particular clinical interest and significance, and to provide recommendations to improve post-LT graft and patient survival. DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: A systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. RESULTS: The literature review and analysis provided show that short-term complications have a large impact on allograft and patient survival after LT. The complications with the strongest effect on survival are acute kidney injury (AKI), biliary complications, and early allograft dysfunction (EAD). CONCLUSION: This panel recommends taking measures to reduce the risk and incidence of short-term complications post-LT. Clinicians should pay particular attention to preventing or ameliorating AKI, biliary complications, and EAD (Quality of evidence; Moderate | Grade of Recommendation; Strong).

Spliceosomal profiling identifies EIF4A3 as a novel oncogene in hepatocellular carcinoma acting through the modulation of FGFR4 splicing.

INTRODUCTION: Altered splicing landscape is an emerging cancer hallmark; however, the dysregulation and implication of the cellular machinery controlling this process (spliceosome components and splicing factors) in hepatocellular carcinoma (HCC) is poorly known. This study aimed to comprehensively characterize the spliceosomal profile and explore its role in HCC. METHODS: Expression levels of 70 selected spliceosome components and splicing factors and clinical implications were evaluated in two retrospective and six in silico HCC cohorts. Functional, molecular and mechanistic studies were implemented in three cell lines (HepG2, Hep3B and SNU-387) and preclinical Hep3B-induced xenograft tumours. RESULTS: Spliceosomal dysregulations were consistently found in retrospective and in silico cohorts. EIF4A3, RBM3, ESRP2 and SRPK1 were the most dysregulated spliceosome elements in HCC. EIF4A3 expression was associated with decreased survival and greater recurrence. Plasma EIF4A3 levels were significantly elevated in HCC patients. In vitro EIF4A3-silencing (or pharmacological inhibition) resulted in reduced aggressiveness, and hindered xenograft-tumours growth in vivo, whereas EIF4A3 overexpression increased tumour aggressiveness. EIF4A3-silencing altered the expression and splicing of key HCC-related genes, specially FGFR4. EIF4A3-silencing blocked the cellular response to the natural ligand of FGFR4, FGF19. Functional consequences of EIF4A3-silencing were mediated by FGFR4 splicing as the restoration of non-spliced FGFR4 full-length version blunted these effects, and FGFR4 inhibition did not exert further effects in EIF4A3-silenced cells. CONCLUSIONS: Splicing machinery is strongly dysregulated in HCC, providing a source of new diagnostic, prognostic and therapeutic options in HCC. EIF4A3 is consistently elevated in HCC patients and associated with tumour aggressiveness and mortality, through the modulation of FGFR4 splicing.

Fast-track protocols in laparoscopic liver surgery: Applicability and correlation with difficulty scoring systems.

BACKGROUND: Few series have reported the utility of fast-track protocols (FTP) in minimally invasive liver surgery. AIM: To report the applicability of FTP in minimally invasive liver surgery and to correlate with difficulty scores. METHODS: The series of patients undergoing minimally invasive liver surgery from 2014 was analyzed. Iwate, Southampton and Gayet's scores were compared as predictors of FTP adherence. Accomplishment of FTP was considered within 24-h, 48-h and 72-h. Multivariate models were performed to define discharge < 24 h, < 72 h, complications and readmissions. RESULTS: From 160 cases, 78 were candidates for FTP, of which 22 (28.2%), 19 (24.4%) and 14 (17.9%) were discharged in < 24-h, 48-h and 72-h, respectively (total = 71.5%). Iwate, Southampton and Gayet's scores achieved area under the receiver operating characteristic values for < 24-h stay of 0.780, 0.687 and 0.698, respectively. Sensitivity and specificity values for the best score (Iwate) were 87.7% and 66.7%, respectively (cutoff = 5.5). In multivariate models, < 72 h stay and complications revealed body mass index as a risk factor independent from difficulty scores. CONCLUSION: The development of aggressive FTP is feasible and < 24-h stay can be achieved even in moderate and advanced complexity cases. Difficulty scores, including body mass index value, may be useful to predict which cases may adhere to these protocols.

Pure laparoscopic major liver resection after yttrium90 radioembolization: a case-matched series analysis of feasibility and outcomes.

BACKGROUND: Liver surgery after radioembolization (RE) entails highly demanding and challenging procedures due to the frequent combination of large tumors, severe RE-related adhesions, and the necessity of conducting major hepatectomies. Laparoscopic liver resection (LLR) and its associated advantages could provide benefits, as yet unreported, to these patients. The current study evaluated feasibility, morbidity, mortality, and survival outcomes for major laparoscopic liver resection after radioembolization. MATERIAL AND METHODS: In this retrospective, single-center study patients diagnosed with hepatocellular carcinoma, intrahepatic cholangiocarcinoma or metastases from colorectal cancer undergoing major laparoscopic hepatectomy after RE were identified from institutional databases. They were matched (1:2) on several pre-operative characteristics to a group of patients that underwent major LLR for the same malignancies during the same period but without previous RE. RESULTS: From March 2011 to November 2020, 9 patients underwent a major LLR after RE. No differences were observed in intraoperative blood loss (50 vs. 150 ml; p = 0.621), operative time (478 vs. 407 min; p = 0.135) or pedicle clamping time (90.5 vs 74 min; p = 0.133) between the post-RE LLR and the matched group. Similarly, no differences were observed on hospital stay (median 3 vs. 4 days; p = 0.300), Clavien-Dindo ≥ III complications (2 vs. 1 cases; p = 0.250), specific liver morbidity (1 vs. 1 case p = 1.000), or 90 day mortality (0 vs. 0; p = 1.000). CONCLUSION: The laparoscopic approach for post radioembolization patients may be a feasible and safe procedure with excellent surgical and oncological outcomes and meets the current standards for laparoscopic liver resections. Further studies with larger series are needed to confirm the results herein presented.

International Expert Consensus on Precision Anatomy for minimally invasive distal pancreatectomy: PAM-HBP Surgery Project.

BACKGROUND: Surgical views with high resolution and magnification have enabled us to recognize the precise anatomical structures that can be used as landmarks during minimally invasive distal pancreatectomy (MIDP). This study aimed to validate the usefulness of anatomy-based approaches for MIDP before and during the Expert Consensus Meeting: Precision Anatomy for Minimally Invasive HBP Surgery (February 24, 2021). METHODS: Twenty-five international MIDP experts developed clinical questions regarding surgical anatomy and approaches for MIDP. Studies identified via a comprehensive literature search were classified using Scottish Intercollegiate Guidelines Network methodology. Online Delphi voting was conducted after experts had drafted the recommendations, with the goal of obtaining >75% consensus. Experts discussed the revised recommendations in front of the validation committee and an international audience of 384 attendees. Finalized recommendations were made after a second round of online Delphi voting. RESULTS: Four clinical questions were addressed, resulting in 10 recommendations. All recommendations reached at least a 75% consensus among experts. CONCLUSIONS: The expert consensus on precision anatomy for MIDP has been presented as a set of recommendations based on available evidence and expert opinions. These recommendations should guide experts and trainees in performing safe MIDP and foster its appropriate dissemination worldwide.

A snapshot of the 2020 conception of anatomic liver resections and their applicability on minimally invasive liver surgery. A preparatory survey for the Expert Consensus Meeting on Precision Anatomy for Minimally Invasive HBP Surgery.

BACKGROUND: The main aim of this survey was to analyze how liver surgeons perform liver resections and to define their conception of anatomic procedures within the incorporation of minimally invasive liver surgery (MILS). METHODS: The survey was distributed among liver surgeons. It mainly focused on personal experience on open and MILS, methods and landmarks, and experience on anatomic resections and Glissonean approach. RESULTS: A total of 445 valid answers from 54 countries was obtained. Surgeons performing MILS mainly have below 10 years of experience (81.8% of responders) and one third has never done complex MILS. New techniques, including indocyanine green demarcation are marginally used (<25%). More than 60% of surgeons do not make a full exposure of hepatic veins during MILS, mainly due to the risk of injury or not considering it to be of utility. Although 88% of responders agreed with the concept of anatomic resection as the "resection along the border/watersheds of each order division identified by the portal vein flow", only 55% of surgeons have ever performed MILS Glissonean approaches. CONCLUSIONS: Liver anatomy is not a static concept. Anatomic resections need training and precision. Standardization of complex anatomic resections by a minimally invasive approach should be encouraged.

International expert consensus on precision anatomy for minimally invasive pancreatoduodenectomy: PAM-HBP surgery project.

BACKGROUND: The anatomical structure around the pancreatic head is very complex and it is important to understand its precise anatomy and corresponding anatomical approach to safely perform minimally invasive pancreatoduodenectomy (MIPD). This consensus statement aimed to develop recommendations for elucidating the anatomy and surgical approaches to MIPD. METHODS: Studies identified via a comprehensive literature search were classified using the Scottish Intercollegiate Guidelines Network method. Delphi voting was conducted after experts had drafted recommendations, with a goal of obtaining >75% consensus. Experts discussed the revised recommendations with the validation committee and an international audience of 384 attendees. Finalized recommendations were made after a second round of online Delphi voting. RESULTS: Three clinical questions were addressed, providing six recommendations. All recommendations reached at least a consensus of 75%. Preoperatively evaluating the presence of anatomical variations and superior mesenteric artery (SMA) and superior mesenteric vein (SMV) branching patterns was recommended. Moreover, it was recommended to fully understand the anatomical approach to SMA and intraoperatively confirm the SMA course based on each anatomical landmark before initiating dissection. CONCLUSIONS: MIPD experts suggest that surgical trainees perform resection based on precise anatomical landmarks for safe and reliable MIPD.

Expert Consensus Guidelines: How to safely perform minimally invasive anatomic liver resection.

BACKGROUND: The concept of minimally invasive anatomic liver resection (MIALR) is gaining popularity. However, specific technical skills need to be acquired to safely perform MIALR. The "Expert Consensus Meeting: Precision Anatomy for Minimally Invasive HBP Surgery (PAM-HBP Surgery Consensus)" was developed as a special program during the 32nd meeting of the Japanese Society of Hepato-Biliary-Pancreatic Surgery (JSHBPS). METHODS: Thirty-four international experts gathered online for the consensus. A Research Committee performed a comprehensive literature review, classifying studies according to the Scottish Intercollegiate Guidelines Network method. Based on the literature review and experts' opinions, tentative recommendations were drafted and circulated among experts using online Delphi Rounds. Finally, formulated recommendations were presented online in the Expert Consensus Meeting of the JSHBPS on February 23rd, 2021. The final recommendations were validated and finalized by the 2nd Delphi Round in May 2021. RESULTS: Seven clinical questions were selected, and 22 recommendations were formulated. All recommendations reached more than 85% consensus among experts at the final Delphi Round. CONCLUSIONS: The Expert Consensus Meeting for safely performing MIALR has presented a set of clinical guidelines based on available literature and experts' opinions. We expect these guidelines to have a favorable effect on the safe implementation and development of MIALR.

The impact of robotics in liver surgery: A worldwide systematic review and short-term outcomes meta-analysis on 2,728 cases.

BACKGROUND: The dissemination of robotic liver surgery is slow-paced and must face the obstacle of demonstrating advantages over open and laparoscopic (LLS) approaches. Our objective was to show the current position of robotic liver surgery (RLS) worldwide and to identify if improved short-term outcomes are observed, including secondary meta-analyses for type of resection, etiology, and cost analysis. METHODS: A PRISMA-based systematic review was performed to identify manuscripts comparing RLS vs open or LLS approaches. Quality analysis was performed using the Newcatle-Ottawa score. Statistical analysis was performed after heterogeneity test and fixed- or random-effect models were chosen accordingly. RESULTS: After removing duplications, 2728 RLS cases were identified from the final set of 150 manuscripts. More than 75% of the cases have been performed on malignancies. Meta-analysis from the 38 comparative reports showed that RLS may offer improved short-term outcomes compared to open procedures in most of the variables screened. Compared to LLS, some advantages may be observed in favour of RLS for major resections in terms of operative time, hospital stay and rate of complications. Cost analyses showed an increased cost per procedure of around US$5000. CONCLUSIONS: The advantages of RLS still need to be demonstrated although early results are promising. Advantages vs open approach are demonstrated. Compared to laparoscopic surgery, minor perioperative advantages may be observed for major resections although cost analyses are still unfavorable to the robotic approach.

World Survey on Minimally Invasive Donor Hepatectomy: A Global Snapshot of Current Practices in 2370 Cases.

BACKGROUND: Having little evidence on the real extent of the minimally invasive donor hepatectomy (MIDH), a world survey was conducted aiming to picture the spread of MIDH and to identify geographical, institutional, and individual differences. METHODS: A web-based survey was created with 5 sections (general, institutional, surgeon's experience, technical, and spread and dissemination), comprising up to a total of 47 questions. A thorough search was carried out to identify all possible centers and surgeons performing MIDH. RESULTS: A global MIDH experience of 2370 cases was collected: 1587 right hepatectomies (RHs; 48.9% pure laparoscopic), 471 left lateral sectionectomies (LLS; 81.1% pure laparoscopic), and 366 left hepatectomies (LHs; 77.6% laparoscopic-assisted). LLS and adult MIDH conversion rates were 5.4% and 3.9%, respectively. Median blood loss was 250 mL (100-600), 100 mL (50-250), and 150 mL (50-500) for RH, LLS, and LH, respectively. Intra- and postoperative transfusion rates were 0.5%, 0%, and 0.3%; and 1.3%, 1.6%, and 0% for RH, LLS, and LH, respectively. Geographically, Asia accounts up to 1730 cases (73% of the global experience, 49.6% pure lap), of which 1374 cases are RH; Europe and Middle East-395 cases-stands out for its experience in left lateral sectionectomy: 289 cases (93% pure lap). Finally, America accounts for 245 cases, using a laparoscopic-assisted technique in 72.6% of the cases (178). CONCLUSIONS: This world survey provides evidence and data on the global spread of MIDH and anticipates how in a near future a large-scale adoption of these techniques may be observed.

Landmarks and techniques to perform minimally invasive liver surgery: A systematic review with a focus on hepatic outflow.

PURPOSE: In this systematic review, we aimed to clarify the useful anatomic structures and assess available surgical techniques and strategies required to safely perform minimally invasive anatomic liver resection (MIALR), with a particular focus on the hepatic veins (HVs). METHODS: A systematic review was conducted using MEDLINE/PubMed for English articles and Ichushi databases for Japanese articles through September 2020. The quality assessment of the articles was performed in accordance with the Scottish Intercollegiate Guidelines Network (SIGN). RESULTS: A total of 3372 studies were obtained, and 59 were selected and reviewed. Due to the limited number of published comparative studies and case series, the degree of evidence from our review was low. Thirty-two articles examined the anatomic landmarks and crucial structures for approaching HVs. Regarding the direction of HV exposure, 32 articles focused on the techniques and advantages of exposing HVs from either the root or the periphery. Ten articles focused on the techniques to perform a segmentectomy 8 in particularly difficult cases of MIALR. In seven articles, bleeding control from HVs was also discussed. CONCLUSIONS: This review may help experts reach a consensus regarding the best approach to the management of hepatic veins during MIALR.

Landmarks to identify segmental borders of the liver: A review prepared for PAM-HBP expert consensus meeting 2021.

BACKGROUND: In preparation for the upcoming consensus meeting in Tokyo in 2021, this systematic review aimed to analyze the current available evidence regarding surgical anatomy of the liver, focusing on useful landmarks, strategies and technical tools to perform precise anatomic liver resection (ALR). METHODS: A systematic review was conducted on MEDLINE/PubMed for English articles and on Ichushi database for Japanese articles until September 2020. The quality assessment of the articles was performed in accordance with the Scottish Intercollegiate Guidelines Network (SIGN). RESULTS: A total of 3169 manuscripts were obtained, 1993 in English and 1176 in Japanese literature. Subsequently, 63 English and 20 Japanese articles were selected and reviewed. The quality assessment of comparative series and case series was revealed to be usually low; only six articles were qualified as high quality. Forty-two articles focused on analyzing intersegmental/sectional planes and their relationship with specific hepatic landmark veins. In 12 articles, the authors aimed to investigate liver surface anatomic structures, while 36 articles aimed to study technological tools and contrast agents for surgical segmentation during ALR. Although Couinaud's classification has remained the cornerstone in daily diagnostic/surgical practices, it does not always portray the realistic liver segmentation and there has been no standardization on which a single strategy should be followed to perform precise ALR. CONCLUSIONS: A global consensus should be pursued in order to establish clear guidelines and proper recommendations to perform ALR in the era of minimally invasive surgery.

Minimally invasive anatomic liver resection: Results of a survey of world experts.

BACKGROUND: Although the number of minimally invasive liver resections (MILRs) has been steadily increasing in many institutions, minimally invasive anatomic liver resection (MIALR) remains a complicated procedure that has not been standardized. We present the results of a survey among expert liver surgeons as a benchmark for standardizing MIALR. METHOD: We administered this survey to 34 expert liver surgeons who routinely perform MIALR. The survey contained questions on personal experience with liver resection, inflow/outflow control methods, and identification techniques of intersegmental/sectional planes (IPs). RESULTS: All 34 participants completed the survey; 24 experts (70%) had more than 11 years of experience with MILR, and over 80% of experts had performed over 100 open resections and MILRs each. Regarding the methods used for laparoscopic or robotic anatomic resection, the Glissonean approach (GA) was a more frequent procedure than the hilar approach (HA). Although hepatic veins were considered essential landmarks, the exposure methods varied. The top three techniques that the experts recommended for identifying IPs were creating a demarcation line, indocyanine green negative staining method, and intraoperative ultrasound. CONCLUSION: Minimally invasive anatomic liver resection remains a challenging procedure; however, a certain degree of consensus exists among expert liver surgeons.