Rapid Liver Hypertrophy After Portal Vein Occlusion Correlates with the Degree of Collateralization Between Lobes-a Study in Pigs

Impact of the extent and location of liver split on future liver remnant hypertrophy after portal vein ligation in a rat model

BACKGROUND

To investigate the role and mechanism of liver parenchyma transection in accelerating the regeneration of future liver remnants in rats with portal vein ligation (PVL).

METHODS

Rats were randomly divided into the PVL group (90% PVL at the caudate lobe, right lobe , left lateral lobe and left median lobe), associating liver partition and portal vein ligation for staged hepatectomy (portal vein ligation with complete liver parenchyma transection [ALPPS]) group (90% PVL with 80 to 90% liver parenchyma transection), PVL + partial liver partition (PLP) group (90% PVL with 30 to 50% liver parenchyma transection), PVL + partition in the ligated lobe (PLL) group (90% PVL with 40 to 60% liver parenchyma transection in the portal vein ligated lobe), PVL + partition in the remnant lobe (PRL) group (90% PVL with 40 to 60% liver parenchyma transection in the remnant lobe), PVL + radiofrequency ablation (RFA) group (90% PVL with splenic ablation) and sham operation (sham) group. The animals were killed at 4 time points of postoperative days 1, 3, 5, and 7. Six rats were killed at each time point, with 24 rats in each group. The weights of the future liver remnant and whole liver were measured. Serum alanine aminotransferase, aspartate aminotransferase, and total bilirubin were analyzed by using an automatic biochemical analyzer. Serum tumor necrosis factor-α, interleukin-6, and hepatocyte growth factor were measured by enzyme-linked immunosorbent assay. The expression of cell proliferating nuclear antigen (Ki67) and phosphorylated histone H3 was detected by immunohistochemistry, and the positive rate was calculated.

RESULTS

The ALPPS group displayed the highest FLR weight to body weight ratio compared with that of the other groups (P < .05), and the partial liver split (PVL + PLP) group also displayed higher remnant weight to body weight ratio than the ectopic liver split (PVL + PLL and PVL + PRL) groups (P < .05). During the first 7 days after surgery the cytokine levels of the ALPPS, PVL + PLP, PVL + PLL and PVL + PRL groups were comparable (P > .05). The PVL + PLP, PVL + PLL, PVL + PRL and PVL + RFA groups showed similar necrotic areas in the portal vein ligated lobe (P > .05). A hemodynamic study revealed that a liver split along the demarcation line could further increase the portal pressure of the FLR and both the split site and completeness were associated with portal hemodynamic alternations and liver hypertrophy. Extrahepatic organ injury (eg, spleen ablation) also has a significant impact on portal hemodynamics and liver regeneration.

CONCLUSION

Complete liver splitting along the demarcation line induced higher portal vein pressure and more rapid FLR hypertrophy than partial or ectopic liver splitting after PVL. The portal hemodynamic alterations after liver split rather than inflammatory cytokine release may be the major cause of ALPPS-induced rapid liver hypertrophy.

Assessment of liver function by gadoxetic acid avidity in MRI in a model of rapid liver regeneration in rats

BACKGROUND

This animal study investigates the hypothesis of an immature liver growth following ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) by measuring liver volume and function using gadoxetic acid avidity in magnetic resonance imaging (MRI) in models of ALPPS, major liver resection (LR) and portal vein ligation (PVL).

METHODS

Wistar rats were randomly allocated to ALPPS, LR or PVL. In contrast-enhanced MRI scans with gadoxetic acid (Primovist®), liver volume and function of the right median lobe (=future liver remnant, FLR) and the deportalized lobes (DPL) were assessed until post-operative day (POD) 5. Liver functionFLR/DPL was defined as the inverse value of time from injection of gadoxetic acid to the blood pool-corrected maximum signal intensityFLR/DPL multiplied by the volumeFLR/DPL.

RESULTS

In ALPPS (n = 6), LR (n = 6) and PVL (n = 6), volumeFLR and functionFLR increased proportionally, except on POD 1. Thereafter, functionFLR exceeded volumeFLR increase in LR and ALPPS, but not in PVL. Total liver function was significantly reduced after LR until POD 3, but never undercuts 60% of its pre-operative value following ALPPS and PVL.

DISCUSSION

This study shows for the first time that functional increase is proportional to volume increase in ALPPS using gadoxetic acid avidity in MRI.

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

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

Optimizing Growth of the Future Liver Remnant and Making In-Situ Liver Transsection Safe—A Standardized Approach to ISLT or ALPPS

In-situ splitting of the liver before extended resection has gained broad attention. This two-step procedure requires several measures to make an effective and safe procedure. Although the procedure is performed in many institutions, there is no consensus on a uniform technique. The two steps can be divided into different parts and a standardized technique may render the procedure safer and the results will be easier to evaluate. In this paper, we describe a detailed approach to in-situ splitting that allows making both procedures safe, avoids liver necrosis, and is easily reproducible. In the first procedure the portal branches to segments I and IV to VIII are divided, the arterial branches and bile ducts to these segments are preserved and encircled and the parenchyma between segments II/III and IVa/b is divided. This avoids necrosis and bile leaks of segments I and IV and avoids urgent completion operations. In particular, the handling of vital structures close to the dissection line seems important to us. Complete splitting and securing the right and middle hepatic vein will make the second step of this procedure a minimal-risk procedure at a stage where the patient is still recovering from the more demanding first step.

Surgical Models of Liver Regeneration in Pigs: A Practical Review of the Literature for Researchers

The remarkable capacity of regeneration of the liver is well known, although the involved mechanisms are far from being understood. Furthermore, limits concerning the residual functional mass of the liver remain critical in both fields of hepatic resection and transplantation. The aim of the present study was to review the surgical experiments regarding liver regeneration in pigs to promote experimental methodological standardization. The Pubmed, Medline, Scopus, and Cochrane Library databases were searched. Studies evaluating liver regeneration through surgical experiments performed on pigs were included. A total of 139 titles were screened, and 41 articles were included in the study, with 689 pigs in total. A total of 29 studies (71% of all) had a survival design, with an average study duration of 13 days. Overall, 36 studies (88%) considered partial hepatectomy, of which four were an associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). Remnant liver volume ranged from 10% to 60%. Only 2 studies considered a hepatotoxic pre-treatment, while 25 studies evaluated additional liver procedures, such as stem cell application, ischemia/reperfusion injury, portal vein modulation, liver scaffold application, bio-artificial, and pharmacological liver treatment. Only nine authors analysed how cytokines and growth factors changed in response to liver resection. The most used imaging system to evaluate liver volume was CT-scan volumetry, even if performed only by nine authors. The pig represents one of the best animal models for the study of liver regeneration. However, it remains a mostly unexplored field due to the lack of experiments reproducing the chronic pathological aspects of the liver and the heterogeneity of existing studies.

Current trends in regenerative liver surgery: Novel clinical strategies and experimental approaches

Liver resections are performed to cure patients with hepatobiliary malignancies and metastases to the liver. However, only a small proportion of patients is resectable, largely because only up to 70% of liver tissue is expendable in a resection. If larger resections are performed, there is a risk of post-hepatectomy liver failure. Regenerative liver surgery addresses this limitation by increasing the future liver remnant to an appropriate size before resection. Since the 1980s, this surgery has evolved from portal vein embolization (PVE) to a multiplicity of methods. This review presents an overview of the available methods and their advantages and disadvantages. The first use of PVE was in patients with large hepatocellular carcinomas. The increase in liver volume induced by PVE equals that of portal vein ligation, but both result only in a moderate volume increase. While awaiting sufficient liver growth, 20%–40% of patients fail to achieve resection, mostly due to the progression of disease. The MD Anderson Cancer Centre group improved the PVE methodology by adding segment 4 embolization (“high-quality PVE”) and demonstrated that oncological results were better than non-surgical approaches in this previously unresectable patient population. In 2012, a novel method of liver regeneration was proposed and called Associating Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS). ALPPS accelerated liver regeneration by a factor of 2–3 and increased the resection rate to 95%–100%. However, ALPPS fell short of expectations due to a high mortality rate and a limited utility only in highly selected patients. Accelerated liver regeneration, however, was there to stay. This is evident in the multiplicity of ALPPS modifications like radiofrequency or partial ALPPS. Overall, rapid liver regeneration allowed an expansion of resectability with increased perioperative risk. But, a standardized low-risk approach to rapid hypertrophy has been missing and the techniques used and in use depend on local expertise and preference. Recently, however, simultaneous portal and hepatic vein embolization (PVE/HVE) appears to offer both rapid hypertrophy and no increased clinical risk. While prospective randomized comparisons are underway, PVE/HVE has the potential to become the future gold standard.

Hepatectomy-Induced Alterations in Hepatic Perfusion and Function - Toward Multi-Scale Computational Modeling for a Better Prediction of Post-hepatectomy Liver Function

Liver resection causes marked perfusion alterations in the liver remnant both on the organ scale (vascular anatomy) and on the microscale (sinusoidal blood flow on tissue level). These changes in perfusion affect hepatic functions via direct alterations in blood supply and drainage, followed by indirect changes of biomechanical tissue properties and cellular function. Changes in blood flow impose compression, tension and shear forces on the liver tissue. These forces are perceived by mechanosensors on parenchymal and non-parenchymal cells of the liver and regulate cell-cell and cell-matrix interactions as well as cellular signaling and metabolism. These interactions are key players in tissue growth and remodeling, a prerequisite to restore tissue function after PHx. Their dysregulation is associated with metabolic impairment of the liver eventually leading to liver failure, a serious post-hepatectomy complication with high morbidity and mortality. Though certain links are known, the overall functional change after liver surgery is not understood due to complex feedback loops, non-linearities, spatial heterogeneities and different time-scales of events. Computational modeling is a unique approach to gain a better understanding of complex biomedical systems. This approach allows (i) integration of heterogeneous data and knowledge on multiple scales into a consistent view of how perfusion is related to hepatic function; (ii) testing and generating hypotheses based on predictive models, which must be validated experimentally and clinically. In the long term, computational modeling will (iii) support surgical planning by predicting surgery-induced perfusion perturbations and their functional (metabolic) consequences; and thereby (iv) allow minimizing surgical risks for the individual patient. Here, we review the alterations of hepatic perfusion, biomechanical properties and function associated with hepatectomy. Specifically, we provide an overview over the clinical problem, preoperative diagnostics, functional imaging approaches, experimental approaches in animal models, mechanoperception in the liver and impact on cellular metabolism, omics approaches with a focus on transcriptomics, data integration and uncertainty analysis, and computational modeling on multiple scales. Finally, we provide a perspective on how multi-scale computational models, which couple perfusion changes to hepatic function, could become part of clinical workflows to predict and optimize patient outcome after complex liver surgery.

Preoperative portal vein or portal and hepatic vein embolization: DRAGON collaborative group analysis

BACKGROUND

The extent of liver resection for tumours is limited by the expected functional reserve of the future liver remnant (FRL), so hypertrophy may be induced by portal vein embolization (PVE), taking 6 weeks or longer for growth. This study assessed the hypothesis that simultaneous embolization of portal and hepatic veins (PVE/HVE) accelerates hypertrophy and improves resectability.

METHODS

All centres of the international DRAGON trials study collaborative were asked to provide data on patients who had PVE/HVE or PVE on 2016-2019 (more than 5 PVE/HVE procedures was a requirement). Liver volumetry was performed using OsiriX MD software. Multivariable analysis was performed for the endpoints of resectability rate, FLR hypertrophy and major complications using receiver operating characteristic (ROC) statistics, regression, and Kaplan-Meier analysis.

RESULTS

In total, 39 patients had undergone PVE/HVE and 160 had PVE alone. The PVE/HVE group had better hypertrophy than the PVE group (59 versus 48 per cent respectively; P = 0.020) and resectability (90 versus 68 per cent; P = 0.007). Major complications (26 versus 34 per cent; P = 0.550) and 90-day mortality (3 versus 16 per cent respectively, P = 0.065) were comparable. Multivariable analysis confirmed that these effects were independent of confounders.

CONCLUSION

PVE/HVE achieved better FLR hypertrophy and resectability than PVE in this collaborative experience.

Hemostasis and Liver Regeneration

The liver is unique in its remarkable regenerative capacity, which enables the use of liver resection as a treatment for specific liver diseases, including removal of neoplastic liver disease. After resection, the remaining liver tissue (i.e, liver remnant) regenerates to maintain normal hepatic function. In experimental settings as well as patients, removal of up to two-thirds of the liver mass stimulates a rapid and highly coordinated process resulting in the regeneration of the remaining liver. Mechanisms controlling the initiation and termination of regeneration continue to be discovered, and many of the fundamental signaling pathways controlling the proliferation of liver parenchymal cells (i.e., hepatocytes) have been uncovered. Interestingly, while hemostatic complications (i.e., bleeding and thrombosis) are primarily thought of as a complication of surgery itself, strong evidence suggests that components of the hemostatic system are, in fact, powerful drivers of liver regeneration. This review focuses on the clinical and translational evidence supporting a link between the hemostatic system and liver regeneration, and the mechanisms whereby the hemostatic system directs liver regeneration discovered using experimental settings.

A better route to ALPPS: minimally invasive vs open ALPPS

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has gained both interest and controversy, as an alternative to portal vein embolisation (PVE) by inducing future liver remnant hypertrophy in patients at risk of liver failure following major hepatectomy. Open ALPPS induces more extensive hypertrophy in a shorter timespan than PVE; however, it is also associated with higher complication rates and mortality. Minimally invasive surgery (MIS), with its known benefits, has been applied to ALPPS in the hope of reducing the surgical insult and improving functional recovery time while preserving the extensive FLR hypertrophy.

METHODS

A search of the PubMed, Medline, EMBASE and Cochrane Library databases was conducted on 10 July 2019. 1231 studies were identified and screened. 19 open ALPPS studies, 3 MIS ALPPS and 1 study reporting on both were included in the analysis.

RESULTS

1088 open and 46 MIS-ALPPS cases were included in the analysis. There were significant differences in the baseline characteristic: open ALPPS patients had a more diverse profile of underlying pathologies (p = 0.028) and comparatively more right extended hepatectomies (p = 0.006) as compared to right hepatectomy and left extended hepatectomy performed. Operative parameters (time and blood loss) did not differ between the two groups. MIS ALPPS had a lower rate of severe Clavien-Dindo complications (≥ IIIa) following stage 1 (p = 0.063) and significantly lower median mortality (0.00% vs 8.45%) (p = 0.007) compared to open ALPPS.

CONCLUSION

Although MIS ALPPS would seem to be better than open ALPPS with reduced morbidity and mortality rates, there is still limited evidence on MIS ALPPS. There is a need for a higher quality of evidence on MIS ALPPS vs. open ALPPS to answer whether MIS ALPPS can replace open ALPPS.

Hypoxia sensing by hepatic stellate cells leads to VEGF-dependent angiogenesis and may contribute to accelerated liver regeneration

Portal vein ligation (PVL) induces liver growth prior to resection. Associating liver partition and portal vein ligation (PVL plus transection=ALPPS) or the addition of the prolyl-hydroxylase inhibitor dimethyloxalylglycine (DMOG) to PVL both accelerate growth via stabilization of HIF-α subunits. This study aims at clarifying the crosstalk of hepatocytes (HC), hepatic stellate cells (HSC) and liver sinusoidal endothelial cells (LSEC) in accelerated liver growth. In vivo, liver volume, HC proliferation, vascular density and HSC activation were assessed in PVL, ALPPS, PVL+DMOG and DMOG alone. Proliferation of HC, HSC and LSEC was determined under DMOG in vitro. Conditioned media experiments of DMOG-exposed cells were performed. ALPPS and PVL+DMOG accelerated liver growth and HC proliferation in comparison to PVL. DMOG alone did not induce HC proliferation, but led to increased vascular density, which was also observed in ALPPS and PVL+DMOG. Activated HSC were detected in ALPPS, PVL+DMOG and DMOG, again not in PVL. In vitro, DMOG had no proliferative effect on HC, but conditioned supernatant of DMOG-treated HSC induced VEGF-dependent proliferation of LSEC. Transcriptome analysis confirmed activation of proangiogenic factors in hypoxic HSC. Hypoxia signaling in HSC induces VEGF-dependent angiogenesis. HSC play a crucial role in the cellular crosstalk of rapid liver regeneration.

A preliminary study of associating liver partition and portal vein ligation for staged hepatectomy in a rat model of liver cirrhosis

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) in a rat model of liver cirrhosis has not, to the best of our knowledge, been previously investigated. The present study therefore aimed to establish a model of ALPPS in cirrhotic rats and to assess liver regeneration. Rats were randomly divided into an ALPPS group with carbon tetrachloride-induced cirrhosis (group A) and a normal liver (group B). Rat weight, cytokine levels, biochemical parameters and histopathology were assessed 1, 2, 3, 7 and 14 days after ALPPS. Higher aspartate aminotransferase and alanine aminotransferase levels were detected in group A on the first postoperative day. On the first, second and third days, hepatocyte proliferation rate was higher in group B than in group A. After 3 days, hepatocyte proliferation rate in group B began to decrease, but the rate in group A continued to increase until the 14th day. Higher levels of hepatocyte growth factor, interleukin-6 and tumor necrosis factor-α were detected in group A compared with group B, but the differences were not significant. The present study demonstrated that ALPPS promoted liver regeneration in a rat model of cirrhosis, but significantly impaired liver function. Compared with the ALPPS model, group B exhibited a delayed peak of proliferation. The mechanism of liver regeneration induced by ALPPS in cirrhotic rats may be associated with increased cytokine levels.

Rapid Induction of Liver Regeneration for Major Hepatectomy (REBIRTH): A Randomized Controlled Trial of Portal Vein Embolisation versus ALPPS Assisted with Radiofrequency

To avoid liver insufficiency following major hepatic resection, portal vein embolisation (PVE) is used to induce liver hypertrophy pre-operatively. Associating liver partition with portal vein ligation for staged hepatectomy assisted with radiofrequency (RALPPS) was introduced as an alternative method. A randomized controlled trial comparing PVE with RALPPS for the pre-operative manipulation of liver volume in patients with a future liver remnant volume (FLRV) ≤25% (or ≤35% if receiving preoperative chemotherapy) was conducted. The primary endpoint was increase in size of the FLRV. The secondary endpoints were length of time taken for the volume gain, morbidity, operation length and post-operative liver function. Between July 2015 and October 2017, 57 patients were randomised to RALPPS (n = 29) and PVE (n = 28). The mean percentage of increase in the FLRV was 80.7 ± 13.7% after a median 20 days following RALPPS compared to 18.4 ± 9.8% after 35 days (p < 0.001) following PVE. Twenty-four patients after RALPPS and 21 after PVE underwent stage-2 operation. Final resection was achieved in 92.3% and 66.6% patients in RALPPS and PVE, respectively (p = 0.007). There was no difference in morbidity, and one 30-day mortality after RALPPS (p = 0.991) was reported. RALPPS is more effective than PVE in increasing FLRV and the number of patients for surgical resection.

Simultaneous hepatic and portal vein ligation induces rapid liver hypertrophy: A study in pigs

BACKGROUND

Liver hypertrophy induced by partial portal vein occlusion (PVL) is accelerated by adding simultaneous parenchymal transection ("ALPPS procedure"). This preclinical experimental study in pigs tests the hypothesis that simultaneous ligation of portal and hepatic veins of the liver also accelerates regeneration by abrogation of porto-portal collaterals without need for operative transection.

METHODS

A pig model of portal vein occlusion was compared with the novel model of simultaneous portal and hepatic vein occlusion, where major hepatic veins draining the portal vein-deprived lobe were identified with intraoperative ultrasonography and ligated using pledgeted transparenchymal sutures. Kinetic growth was compared, and the portal vein system was then studied after 7 days using epoxy casts of the portal circulation. Portal vein flow and portal pressure were measured, and Ki-67 staining was used to evaluate the proliferative response.

RESULTS

Pigs were randomly assigned to portal vein occlusion (n = 8) or simultaneous portal and hepatic vein occlusion (n = 6). Simultaneous portal and hepatic vein occlusion was well tolerated and led to mild cytolysis, with no necrosis in the outflow vein-deprived liver sectors. The portal vein-supplied sector increased by 90 ± 22% (mean ± standard deviation) after simultaneous portal and hepatic vein occlusion compared with 29 ± 18% after PVL (P < .001). Collaterals to the deportalized liver developed after 7 days in both procedures but were markedly reduced in simultaneous portal and hepatic vein occlusion. Ki-67 staining at 7 days was comparable.

CONCLUSION

This study in pigs found that simultaneous portal and hepatic vein occlusion led to rapid hypertrophy without necrosis of the deportalized liver. The findings suggest that the use of simultaneous portal and hepatic vein occlusion accelerates liver hypertrophy for extended liver resections and should be evaluated further.

Hepatic regeneration by associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is feasible but attenuated in rat liver with thioacetamide-induced fibrosis

BACKGROUND

The associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) procedure promotes the proliferation of the future liver remnant, but evidence to support the feasibility of ALPPS in livers with fibrosis is needed. Therefore the aim of this study was to establish a fibrotic ALPPS model in the rat to compare the capacity of regeneration in the remnant liver with or without fibrosis.

METHODS

In our study we first established a thioacetamide-induced fibrotic ALPPS model in rats. Then the ALPPS-induced regenerative capacities of normal and fibrotic liver were compared in this animal model. In addition, markers of regeneration, including the proliferative index and cyclin D1 and proliferating cell nuclear antigen levels, as well as various indicators of liver function were determined to evaluate the quality of the hepatic regeneration.

RESULTS

Compared with that of the sham group (opening of the peritoneal cavity with no further operative manipulation), the proliferation of the future liver remnant in fibrotic rat liver after the ALPPS procedure was increased on postoperative days 1, 2, and 5 (P < .039 each). In addition, the proliferative response was greater in the ALPPS group than in the ligation group subjected only to portal vein ligation of the left lateral, left middle, right, and caudate lobes (P = .099, P = .006, and P = .020 on postoperative days 1, 2, and 5, respectively). In contrast, the ALPPS-induced regenerative capacity in the fibrotic rat livers was attenuated compared with that in the normal liver on postoperative days 1, 2, and 5 (P < .031 for each) after stage I and on postoperative day 5 after stage II of the ALPPS procedure (P < .005). This attenuated the recovery of liver function, and the greater mortality rate indicated that functional proliferation was either delayed or not as extensive in the fibrotic rat livers.

CONCLUSION

Through establishing a rat model of thioacetamide-induced liver fibrosis, we found that ALPPS-derived liver regeneration was present and feasible in fibrotic livers, but this effect was attenuated compared with that in normal liver.

The HPB controversy of the decade: 2007-2017 - Ten years of ALPPS

Ten years ago the first patient underwent Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS). This report aimed to critically review literature on ALPPS in terms of methods, outcomes, and bias. In total, 237 English papers on ALPPS were identified, 75 (32%) were letters and 43 (18%) case-reports. Forty-nine single-center series reported a median 10 patients, with 0-69% morbidity and 0-50% mortality. The indications for ALPPS were reported in 35% and 47% reported on modifications. Twenty-three multicenter series included a median 45 patients. Some reports excluded up to 399 cases. 26% reported on the indications and 35% on ALPPS modifications. Across journals, variation in positive and negative conclusions on ALPPS was observed. Ten years of ALPPS have resulted in diverse publications with a high concern of bias. Although one randomized study has been published, a more critical approach towards retrospective methodology is needed to allow pragmatic conclusions for HPB-surgeons.