Standardized measurement of the future liver remnant prior to extended liver resection: methodology and clinical associations

Indicating ALPPS for Colorectal Liver Metastases: A Critical Analysis of Patients in the International ALPPS Registry

OBJECTIVES

In the international associating liver partition and portal vein ligation for staged hepatectomy registry, more than 50% of patients underwent associating liver partition and portal vein ligation for staged hepatectomy with a right hepatectomy. This study evaluated the necessity of two-stage hepatectomies being performed as right hepatectomy associating liver partition and portal vein ligation for staged hepatectomy in patients with colorectal liver metastases versus right trisectionectomy associating liver partition and portal vein ligation for staged hepatectomy.

PATIENTS AND METHODS

All patients registered between 2012 and 2017 undergoing associating liver partition and portal vein ligation for staged hepatectomy for colorectal liver metastases were included. A liver to body weight index of 0.5 or less prior to stage I in the presence of liver damage was used as an internationally accepted standard to justify a two-stage hepatectomy.

RESULTS

Four-hundred and three patients with colorectal liver metastases with right hepatectomy associating liver partition and portal vein ligation for staged hepatectomy (n = 183) or right trisectionectomy associating liver partition and portal vein ligation for staged hepatectomy (n = 220) were analyzed. Presence of metastases in segments II/III, liver damage, number of patients on chemotherapy, and cycles were comparable, and there was a comparable response to chemotherapy. Liver to body weight index was different prior to stage 1 (right trisectionectomy associating liver partition and portal vein ligation for staged hepatectomy: 0.33 ± 0.12 versus right hepatectomy associating liver partition and portal vein ligation for staged hepatectomy: 0.40 ± 0,14; P < .001) and prior to stage 2 (right trisectionectomy associating liver partition and portal vein ligation for staged hepatectomy: 0.58 ± 0.17 versus right hepatectomy associating liver partition and portal vein ligation for staged hepatectomy: 0.66 ± 0,18; P < .001). Hypertrophy rates were similar between groups. As much as 16.9% and 7.2% of patients in right hepatectomy associating liver partition and portal vein ligation for staged hepatectomy and right trisectionectomy associating liver partition and portal vein ligation for staged hepatectomy had no apparent justification for a two-stage hepatectomy based on LBWI prior to stage 1 and absence of chemotherapy (<12 cycles).

CONCLUSION

More than 15% of associating liver partition and portal vein ligation for staged hepatectomy procedures were performed in patients who may have had no indication for a two-stage hepatectomy, especially in the group of patients with right hepatectomy. Thus, it appears that there is a risk of the overuse of associating liver partition and portal vein ligation for staged hepatectomy because of its great potential to induce volume growth. Due to the high perioperative risk of associating liver partition and portal vein ligation for staged hepatectomy, indications should be carefully reconsidered.

Serial Assessment of Growth Factors Associated with Liver Regeneration in Patients Operated with Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy

BACKGROUND

There is limited knowledge about the mechanisms behind the unparalleled growth of the future liver remnant (FLR) linked to associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). In this study, liver regenerative markers were examined in patients subjected to ALPPS.

METHODS

Ten patients with colorectal liver metastases treated with neoadjuvant chemotherapy and ALPPS were included. Plasma was sampled at 6 time points and biopsies from both liver lobes were collected at both stages of ALPPS. The levels of interleukin (IL)-6, hepatocyte growth factor (HGF), tumor necrosis factor-α, epidermal growth factor, and vascular endothelial growth factor in plasma were measured at each time point. Expression of mRNA for markers of proliferation and apoptosis was studied in the biopsies from both liver lobes taken at both stages.

RESULTS

ALPPS resulted in a peak of IL-6 after stage 1 (p = 0.004), which decreased rapidly and did not increase again after stage 2. HGF also increased after stage 1 (p = 0.048), and the HGF levels correlated significantly with the degree of growth of the FLR before stage 2 (p = 0.02, r2 = 0.47). There was a correlation between peak levels of IL-6 and HGF (p = 0.03, r2 = 0.84).

CONCLUSIONS

IL-6 and HGF seem to be early mediators of hypertrophy after stage 1 in the ALPPS procedure. The peak HGF plasma level correlates with the degree of FLR growth in patients subjected to ALPPS.

Utility of 3D Reconstruction of 2D Liver Computed Tomography/Magnetic Resonance Images as a Surgical Planning Tool for Residents in Liver Resection Surgery

OBJECTIVE

A fundamental aspect of surgical planning in liver resections is the identification of key vessel tributaries to preserve healthy liver tissue while fully resecting the tumor(s). Current surgical planning relies primarily on the surgeon's ability to mentally reconstruct 2D computed tomography/magnetic resonance (CT/MR) images into 3D and plan resection margins. This creates significant cognitive load, especially for trainees, as it relies on image interpretation, anatomical and surgical knowledge, experience, and spatial sense. The purpose of this study is to determine if 3D reconstruction of preoperative CT/MR images will assist resident-level trainees in making appropriate operative plans for liver resection surgery.

DESIGN

Ten preoperative patient CT/MR images were selected. Images were case-matched, 5 to 2D planning and 5 to 3D planning. Images from the 3D group were segmented to create interactive digital models that the resident can manipulate to view the tumor(s) in relation to landmark hepatic structures. Residents were asked to evaluate the images and devise a surgical resection plan for each image. The resident alternated between 2D and 3D planning, in a randomly generated order. The primary outcome was the accuracy of resident's plan compared to expert opinion. Time to devise each surgical plan was the secondary outcome. Residents completed a prestudy and poststudy questionnaire regarding their experience with liver surgery and the 3D planning software.

SETTING AND PARTICIPANTS

Senior level surgical residents from the Queen's University General Surgery residency program were recruited to participate.

RESULTS

A total of 14 residents participated in the study. The median correct response rate was 2 of 5 (40%; range: 0-4) for the 2D group, and 3 of 5 (60%; range: 1-5) for the 3D group (p < 0.01). The average time to complete each plan was 156 ± 107 seconds for the 2D group, and 84 ± 73 seconds for the 3D group (p < 0.01). A total 13 of 14 residents found the 3D model easier to use than the 2D. Most residents noticed a difference between the 2 modalities and found that the 3D model improved their confidence with the surgical plan proposed.

CONCLUSIONS

The results of this study show that 3D reconstruction for liver surgery planning increases accuracy of resident surgical planning and decreases amount of time required. 3D reconstruction would be a useful model for improving trainee understanding of liver anatomy and surgical resection, and would serve as an adjunct to current 2D planning methods. This has the potential to be developed into a module for teaching liver surgery in a competency-based medical curriculum.

Increasing the remnant liver volume using portal vein embolization

Background: Portal vein embolization (PVE) is a common procedure to induce hypertrophy of the remnant liver (RL) before major hepatectomy. Objective: Evaluate increased RL volume after PVE based on CT volumetric measurement. Methods: Multi-detector computed tomography (MDCT) was used to measure hepatic volumetric measurement, including total liver volume and RL volumes of pre- and post-PVE. Complications were recorded from PVE and from three-month after post-extended hepatectomy liver dysfunction. Result and conclusion: There was a 10% increase in RL volume. Mean days between CT and PVE were 20 days. No major complications from PVE were observed.

Update on Liver Failure Following Hepatic Resection: Strategies for Prediction and Avoidance of Post-operative Liver Insufficiency

Liver resection is increasingly used for a variety of benign and malignant conditions. Despite advances in preoperative selection, surgical technique and perioperative management, posthepatectomy liver failure (PHLF) is still a leading cause of morbidity and mortality following liver resection. Given the devastating physiological consequences of PHLF and the lack of effective treatment options, identifying risk factors and preventative strategies for PHLF is paramount. In the past, a major limitation to conducting high quality research on risk factors and prevention strategies for PHLF has been the absence of a standardized definition. In this article, we describe relevant definitions for PHLF, discuss risk factors and prediction models, and review advances in liver assessment tools and PHLF prevention strategies.

Quantitative Imaging Features and Postoperative Hepatic Insufficiency: A Multi-Institutional Expanded Cohort

BACKGROUND

Post-hepatectomy liver insufficiency (PHLI) is a significant cause of morbidity and mortality after liver resection. Quantitative imaging analysis using CT scans measures variations in pixel intensity related to perfusion. A preliminary study demonstrated a correlation between quantitative imaging features of the future liver remnant (FLR) parenchyma from preoperative CT scans and PHLI. The objective of this study was to explore the potential application of quantitative imaging analysis in PHLI in an expanded, multi-institutional cohort.

STUDY DESIGN

We retrospectively identified patients from 5 high-volume academic centers who developed PHLI after major hepatectomy, and matched them to control patients without PHLI (by extent of resection, preoperative chemotherapy treatment, age [±5 years], and sex). Quantitative imaging features were extracted from the FLR in the preoperative CT scan, and the most discriminatory features were identified using conditional logistic regression. Percent remnant liver volume (RLV) was defined as follows: (FLR volume)/(total liver volume) × 100. Significant clinical and imaging features were combined in a multivariate analysis using conditional logistic regression.

RESULTS

From 2000 to 2015, 74 patients with PHLI and 74 matched controls were identified. The most common indications for surgery were colorectal liver metastases (53%), hepatocellular carcinoma (37%), and cholangiocarcinoma (9%). Two CT imaging features (FD1_4: image complexity; ACM1_10: spatial distribution of pixel intensity) were strongly associated with PHLI and remained associated with PHLI on multivariate analysis (p = 0.018 and p = 0.023, respectively), independent of clinical variables, including preoperative bilirubin and %RLV.

CONCLUSIONS

Quantitative imaging features are independently associated with PHLI and are a promising preoperative risk stratification tool.

Prediction of small for size syndrome after extended hepatectomy: Tissue characterization by relaxometry, diffusion weighted magnetic resonance imaging and magnetization transfer

This study aimed to monitor the course of liver regeneration by multiparametric magnetic-resonance imaging (MRI) after partial liver resection characterizing Small-for-Size Syndrome (SFSS), which frequently leads to fatal post-hepatectomy liver failure (PLF). Twenty-two C57BL/6 mice underwent either conventional 70% partial hepatectomy (cPH), extended 86% partial hepatectomy (ePH) or SHAM operation. Subsequent MRI scans on days 0, 1, 2, 3, 5 and 7 in a 4.7T MR Scanner quantified longitudinal and transverse relaxation times, apparent diffusion coefficient (ADC) and the magnetization-transfer ratio (MTR) of the regenerating liver parenchyma. Histological examination was performed by hematoxylin-eosin staining. After hepatectomy, an increase of T1 time was detected being larger for ePH on day 1: 18% for cPH vs. 40% for ePH and on day 2: 24% for cPH vs. 49% for ePH. An increase in T2 time, again greater in ePH was most pronounced on day 5: 21% for cPH vs. 41% for ePH. ADC and MTR showed a decrease on day 1: 21% for ePH vs. 13% for cPH for ADC, 15% for ePH vs. 11% for cPH for MTR. Subsequently, all MR parameters converged towards initial values in surviving animals. Dying PLF animals exhibited the strongest increase of T1 relaxation time and most prominent decreases of ADC and MTR. The retrieved MRI biomarkers indicate SFSS and potentially developing PLF at an early stage, likely reflecting cellular hypertrophy with extended water content and concomitantly diluted cellular components as features of liver regeneration, appearing more intense in ePH as compared to cPH.

Two-Stage Hepatectomy vs One-Stage Major Hepatectomy with Contralateral Resection or Ablation for Advanced Bilobar Colorectal Liver Metastases

BACKGROUND

Both 2-stage hepatectomy (TSH) and 1-stage hepatectomy (OSH) represent feasible strategies for resection of advanced bilobar colorectal liver metastases (CLM). However, the influence of the surgical approach on postoperative outcomes and overall survival (OS) is unknown. To define the optimal surgical approach for advanced bilobar CLM requiring right hemihepatectomy, we compared short-term and long-term outcomes after TSH and OSH with contralateral resection or radiofrequency ablation (RFA).

STUDY DESIGN

We retrospectively reviewed 227 patients with bilobar CLM, who underwent right or extended right hepatectomy with treatment of synchronous CLM in segments I, II, and/or III, between 1998 and 2015. Postoperative outcomes and OS were compared between patients who underwent TSH and those who underwent OSH.

RESULTS

Of the 227 patients, 126 (56%) underwent at least the first stage of TSH, and 101 (44%) underwent OSH, 29 (13%) without RFA and 72 (32%) with RFA. Two-stage hepatectomy was associated with a lower incidence of postoperative major complications (14% vs 26%, p = 0.03) and postoperative hepatic insufficiency (6% vs 20%, p = 0.001) than OSH. The 5-year OS rate was higher for patients assigned to TSH than for those who underwent OSH (35% vs 24%, p = 0.016). Patients who completed both stages of TSH had a higher 5-year OS rate than patients who underwent OSH without RFA (50% vs 20%, p = 0.023) or OSH with RFA (50% vs 24%, p < 0.0001).

CONCLUSIONS

In patients with advanced bilobar CLM, TSH is associated with fewer complications than OSH. Both TSH in intention-to-treat analysis and completed TSH in as-treated analysis were associated with better OS than OSH.

Did the International ALPPS Meeting 2015 Have an Impact on Daily Practice? The Hamburg Barmbek Experience of 58 Cases

BACKGROUND

ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) was introduced only 10 years ago and has gained wide acceptance as a variation of staged procedures in liver surgery. It has been criticized for its high morbidity and mortality, which all centers reported in their initial series.

METHODS

After a world expert meeting in Hamburg in 2015 where all experts in the field met to discuss this method, caveats were extracted and formulated. We researched our complete prospective ALPPS database to see if the recommendations had any impact on outcome.

RESULTS

In total, we performed 58 ALPPS procedures in our center. 33 patients were operated on before, 25 after the meeting. Results in terms of morbidity and mortality were significantly better after the meeting, as were patient selection and strategy.

CONCLUSION

In our own center's experience, the implementation of the meetings' recommendations and the information gathered through this valuable exchange had a dramatic impact on results. Having performed 58 ALPPS procedures in total, we can now conclude that ALPPS has become much safer in our hands since the 2015 meeting and that morbidity and mortality are no longer the issue to be discussed. Future research must focus on oncologic outcomes in these patients.

Current Modalities for the Assessment of Future Remnant Liver Function

While imaging studies such as computed tomography or magnetic resonance imaging allow the volumetric assessment of the liver segments, only indirect information is provided concerning the quality of the liver parenchyma and its actual functional capacity. Assessment of liver function is therefore crucial in the preoperative workup of patients who require extensive liver resection and in whom portal vein embolization is considered. This review deals with the modalities currently available for the measurement of liver function. Passive liver function tests include biochemical parameters and clinical grading systems such as the Child-Pugh and MELD scores. Dynamic quantitative tests of liver function can be based on clearance capacity tests such as the indocyanine green (ICG) clearance test. Although widely used, discrepancies have been reported for the ICG clearance test in relation with clinical outcome. Nuclear imaging studies have the advantage of providing simultaneous morphologic (visual) and physiologic (quantitative functional) information about the liver. In addition, regional (segmental) differentiation allows specific functional assessment of the future remnant liver. Technetium-99m (^99mTc)-galactosyl human serum albumin scintigraphy and ^99mTc-mebrofenin hepatobiliary scintigraphy potentially identify patients at risk for post-resectional liver failure who might benefit from liver-augmenting techniques. As there is no one test that can measure all the components of liver function, liver functional reserve is estimated based on a combination of clinical parameters and quantitative liver function tests.

Experimental evaluation of liver regeneration patterns and liver function following ALPPS

Background

The underlying mechanism of liver regeneration after Associating Liver Partition and Portal vein ligation (PVL) for Staged hepatectomy (ALPPS) is still unclear. The aim of this study was to evaluate the relationship between future liver remnant (FLR) volume, liver regeneration characteristics and restoration of function in an experimental model of ALPPS.

Methods

An ALPPS model in rats was developed with selective PVL, parenchymal transection and partial hepatectomy (step 1), followed by resection of the liver (step 2). Three different ALPPS groups with FLR sizes of 30, 20 and 10 per cent of total liver volume were compared with sham‐operated controls and animals undergoing resection of left lateral lobe and 90 per cent PVL with respect to morbidity, mortality, liver regeneration and function.

Results

Three of 15 animals that had ALPPS with 10 per cent FLR (ALPPS10) died after step 1. Ascites developed in two of five rats that had ALPPS with 20 per cent FLR and in three of four animals in the ALPPS10 group after step 2. Although the relative increments in FLR size and growth rates were highest in the ALPPS groups, small FLR size was associated with a sustained increase in levels of serum aminotransferases and bilirubin, a lower albumin concentration, severe sinusoidal injury, increased expression of proliferation markers and increased activation of hepatic progenitor cells after step 2.

Conclusion

There is discordance between FLR volume increase and functional restoration after the ALPPS procedure.

99mTc-mebrofenin hepatobiliary scintigraphy predicts liver failure following major liver resection for perihilar cholangiocarcinoma

BACKGROUND

Posthepatectomy liver failure (PHLF) is a threatening complication after liver surgery, especially in perihilar cholangiocarcinoma (PHC). This study aimed to assess the value of preoperative assessment of liver function using ^99mTc-mebrofenin hepatobiliary scintigraphy (HBS) to predict PHLF in comparison with liver volume in PHC patients.

METHODS

All patients who underwent resection of suspected PHC in a single center between 2000 and 2015 were included in the analysis. PHLF was graded according to the ISGLS criteria with grade B/C considered clinically relevant. A cut-off value for the prediction of PHLF was calculated using the receiver operating characteristic curve (ROC) analysis.

RESULTS

A total of 116 patients were included of which 27 (23%) suffered of PHLF. ROC values for the prediction of PHLF were 0.74 (0.63-0.86) for future liver remnant function and 0.63 (0.47-0.80) for volume. A cut-off for liver function was set at 8.5%/min, which resulted in a negative predictive value of 94% and positive predictive value of 41%.

CONCLUSIONS

Assessment of liver function with HBS had better predictive value for PHLF than liver volume in patients undergoing major liver resection for suspected PHC. The cut-off of 8.5%/min can help to select patients for portal vein embolization and might help to reduce postoperative liver failure.

The Pitfalls of Left Trisectionectomy or Central Bisectionectomy for Biliary Cancer: Anatomical Classification Based on the Ventral Branches of Segment VI Portal Vein Relative to the Right Hepatic Vein

BACKGROUNDS

Some patients have P6a running on the ventral side (Ventral-P6a), relative to the right hepatic vein (RHV).

STUDY DESIGN

Forty-one patients who underwent left trisectionectomy or central bisectionectomy for biliary cancer were enrolled. We compared the anatomical features using 3D images and surgical outcomes between patients with Ventral-P6a (n = 17) and those with P6a running on the dorsal side relative to the RHV (Dorsal-P6a; n = 25). Moreover, the liver volume by hand-tracing 2D axial images was compared to the volume calculated using the 3D images.

RESULTS

The frequency of complete exposure of RHV on the transection plane was less in Ventral-P6a (12 vs. 76%; p < 0.001), and the frequency of supraportal type of right posterior hepatic artery (RPHA, 29 vs. 4%, p = 0.020), the presence of inferior RHV (47 vs. 12%, p = 0.011), and the angle between the transection plane of segment VI and VII (S6-S7angle, 29.0° vs. 4.9°; p < 0.001) were greater in Ventral-P6a than in Dorsal-P6a. In Dorsal-P6a, the volume of posterior section calculated using 2D images was greater than that calculated using 3D images (404 vs. 370 mL; p = 0.004). The incidence of daily diuretic administration in Dorsal-P6a was greater than in Ventral-P6a (88 vs. 54%, p = 0.035).

CONCLUSION AND RELEVANCE

In Ventral-P6a, the complete exposure of RHV was rare in left trisectionectomy or central bisectionectomy. Surgeons should preoperatively recognize the course of RPHA, the presence of inferior RHV, and the S6-S7angle. In Dorsal-P6a, the volume of posterior section, which tended to be overestimated using 2D images, was smaller than that in Ventral-P6a.

Rat Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) Procedure

Recent clinical data support an aggressive surgical approach to both primary and metastatic liver tumors. For some indications, like colorectal liver metastases, the amount of liver tissue left behind after liver resection has become the main limiting factor of resectability of large or multiple liver tumors. A minimal amount of functional tissue is required to avoid the severe complication of post-hepatectomy liver failure, which has high morbidity and mortality. Inducing liver growth of the prospective remnant prior to resection has become more established in liver surgery, either in the form of portal vein embolization by interventional radiologists or in the form of portal vein ligation several weeks prior to resection. Recently, it was shown that liver regeneration is more extensive and rapid, when the parenchymal transection is added to portal vein ligation in a first stage and then, after only one week of waiting, resection performed in a second stage (Associating Liver Partition and Portal vein ligation for Staged hepatectomy = ALPPS). ALPPS has rapidly become popular across the world, but has been criticized for its high perioperative mortality. The mechanism of accelerated and extensive growth induced by this procedure has not been well understood. Animal models have been developed to explore both the physiological and molecular mechanisms of accelerated liver regeneration in ALPPS. This protocol presents a rat model that allows mechanistic exploration of accelerated regeneration.

Hepatic atrophy following preoperative chemotherapy predicts hepatic insufficiency after resection of colorectal liver metastases

BACKGROUND & AIMS

For patients with colorectal liver metastases (CLM) undergoing major hepatectomy, extensive preoperative chemotherapy has been associated with increased morbidity and mortality. The impact of extensive chemotherapy on total liver volume (TLV) change is unclear. The aims of the current study were twofold: (1) to determine the change of TLV following preoperative chemotherapy in patients undergoing resection for CLM and (2) to investigate the correlations among TLV change, postoperative hepatic insufficiency (PHI), and death from liver failure.

METHODS

Clinicopathological features of patients with CLM who underwent preoperative chemotherapy and curative resection were reviewed (2008-2015). TLV change (degree of atrophy) was defined as the percentage difference of TLV (estimated by manual volumetry)/standardized liver volume (SLV) ratio: ([Pre-chemotherapy TLV]-[Post-chemotherapy TLV])×100÷SLV (%). Receiver operating characteristic (ROC) analysis was performed to decide the accurate cut-off value of degree of atrophy to predict PHI. The Cox proportional hazard model was performed to identify the predictors of severe degree of atrophy and PHI.

RESULTS

The study cohort consisted of 459 patients, of which 154 patients (34%) underwent extensive preoperative chemotherapy (≥7 cycles). ROC analysis identified the degree of atrophy ≥10% as an accurate cut-off to predict PHI, which was significantly correlated with ≥7 cycles of preoperative chemotherapy. Four factors independently predicted PHI: standardized future liver remnant ≤30% (odds ratio [OR] 4.03, p=0.019), high aspartate aminotransferase-to-platelet ratio index (OR 5.27, p=0.028), degree of atrophy ≥10% (OR 43.5, p<0.001), and major hepatic resection (OR 5.78, p=0.005). Degree of atrophy ≥10% was associated with increased mortality from liver failure (0% [0/374] vs. 15% [13/85], p<0.001).

CONCLUSION

Extensive preoperative chemotherapy induced significant atrophic change of TLV. Degree of atrophy ≥10% is an independent predictor of PHI and death in patients with CLM undergoing preoperative chemotherapy and resection.

LAY SUMMARY

Extensive preoperative chemotherapy for patients with colorectal liver metastases (CLM) could induce hepatic atrophy. A higher degree of atrophy is an independent predictor of postoperative hepatic insufficiency and death in patients with CLM undergoing preoperative chemotherapy and resection.

Liver segmentation: indications, techniques and future directions

OBJECTIVES

Liver volumetry has emerged as an important tool in clinical practice. Liver volume is assessed primarily via organ segmentation of computed tomography (CT) and magnetic resonance imaging (MRI) images. The goal of this paper is to provide an accessible overview of liver segmentation targeted at radiologists and other healthcare professionals.

METHODS

Using images from CT and MRI, this paper reviews the indications for liver segmentation, technical approaches used in segmentation software and the developing roles of liver segmentation in clinical practice.

RESULTS

Liver segmentation for volumetric assessment is indicated prior to major hepatectomy, portal vein embolisation, associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) and transplant. Segmentation software can be categorised according to amount of user input involved: manual, semi-automated and fully automated. Manual segmentation is considered the "gold standard" in clinical practice and research, but is tedious and time-consuming. Increasingly automated segmentation approaches are more robust, but may suffer from certain segmentation pitfalls. Emerging applications of segmentation include surgical planning and integration with MRI-based biomarkers.

CONCLUSIONS

Liver segmentation has multiple clinical applications and is expanding in scope. Clinicians can employ semi-automated or fully automated segmentation options to more efficiently integrate volumetry into clinical practice.

TEACHING POINTS

• Liver volume is assessed via organ segmentation on CT and MRI examinations. • Liver segmentation is used for volume assessment prior to major hepatic procedures. • Segmentation approaches may be categorised according to the amount of user input involved. • Emerging applications include surgical planning and integration with MRI-based biomarkers.

Prediction of surgical outcomes of laparoscopic liver resections for hepatocellular carcinoma by defining surgical difficulty

BACKGROUND

Several classification systems for assessing the surgical difficulty of laparoscopic liver resection (LLR) have been proposed. We evaluated three current classification systems, including traditional Major/Minor Classification, Complexity Classification, and the Difficulty Scoring System for predicting the surgical outcomes after LLR.

METHODS

We reviewed the clinical data of 301 patients who underwent LLR for hepatocellular carcinoma between March 1, 2004 and June 30, 2015. We compared the intraoperative, pathologic, and postoperative outcomes according to the three classifications. We also compared the prognostic value of the three classifications using receiver operating characteristic (ROC) curves.

RESULTS

The Major/Minor Classification, Complexity Classification, and the Difficulty Scoring System efficiently differentiated surgical difficulty in terms of blood loss (P = 0.001, P = 0.009, and P < 0.001, respectively) and operation time (all P < 0.001). Regarding intraoperative outcomes, the Difficulty Scoring System and Complexity Classification successfully differentiated the transfusion rate (P = 0.001 and P < 0.001, respectively). However, only the Complexity Classification adequately predicted severe postoperative complications (P = 0.032), the severity of complications (P < 0.001), and the length of hospital stay (P = 0.005). In ROC curve analysis, the Complexity Classification (area under the curve [AUC] = 0.611) outperformed the Major/Minor Classification (AUC = 0.544) and the Difficulty Scoring System (AUC = 0.530) for predicting severe postoperative complications. None of the classification systems predicted recurrence or patient survival.

CONCLUSION

The Complexity Classification was superior to the other methods for assessing surgical difficulty and predicting complications after LLR for hepatocellular carcinoma.

Measuring hepatic functional reserve using T1 mapping of Gd-EOB-DTPA enhanced 3T MR imaging: A preliminary study comparing with 99mTc GSA scintigraphy and signal intensity based parameters

PURPOSE

To determine the utility of liver T1-mapping on gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance (MR) imaging for the measurement of liver functional reserve compared with the signal intensity (SI) based parameters, technetium-99m-galactosyl serum albumin (^99mTc-GSA) scintigraphy and indocyanine green (ICG) clearance.

MATERIALS AND METHODS

This retrospective study included 111 patients (Child-Pugh-A 90; -B 21) performed with both Gd-EOB-DTPA enhanced liver MR imaging and ^99mTc-GSA (76 patients with ICG). Receiver operating characteristic (ROC) curve analysis was performed to compare diagnostic performances of T1-relaxation-time parameters [pre-(T1pre) and post-contrast (T1hb) Gd-EOB-DTPA], SI based parameters [relative enhancement (RE), liver-to-muscle-ratio (LMR), liver-to-spleen-ratio (LSR)] and ^99mTc-GSA scintigraphy blood clearance index (HH15)] for Child-Pugh classification. Pearson's correlation was used for comparisons among T1-relaxation-time parameters, SI-based parameters, HH15 and ICG.

RESULTS

A significant difference was obtained for Child-Pugh classification with T1hb, ΔT1, all SI based parameters and HH15. T1hb had the highest AUC followed by RE, LMR, LSR, ΔT1, HH15 and T1pre. The correlation coefficients with HH15 were T1pre 0.22, T1hb 0.53, ΔT1 -0.38 of T1 relaxation parameters; RE -0.44, LMR -0.45, LSR -0.43 of SI-based parameters. T1hb was highest for correlation with HH15. The correlation coefficients with ICG were T1pre 0.29, T1hb 0.64, ΔT1 -0.42 of T1 relaxation parameters; RE -0.50, LMR -0.61, LSR -0.58 of SI-based parameters; 0.64 of HH15. Both T1hb and HH15 were highest for correlation with ICG.

CONCLUSION

T1 relaxation time at post-contrast of Gd-EOB-DTPA (T1hb) was strongly correlated with ICG clearance and moderately correlated HH15 with ^99mTc-GSA. T1hb has the potential to provide robust parameter of liver functional reserve.

Portal vein ligation versus portal vein embolization for induction of hypertrophy of the future liver remnant: A systematic review and meta-analysis

An important risk of major hepatic resection is postoperative liver failure, which is directly related to insufficient future liver remnant (FLR). Portal vein embolization (PVE) and portal vein ligation (PVL) can minimize this risk by inducing hypertrophy of the FLR. The aim of this systematic review and meta-analysis was to compare the efficacy and safety of PVE and PVL for FLR hypertrophy. A systematic search was conducted on the17^th of January 2017. The methodological quality of the studies was assessed using the Oxford Critical Appraisal Skills Program for cohort studies. The primary endpoint was the relative rate of hypertrophy of the FLR. Number of cancelled hepatic resection and postoperative morbidity and mortality were secondary endpoints. For meta-analysis, the pooled hypertrophy rate was calculated for each intervention. The literature search identified 21 eligible studies with 1953 PVE and 123 PVL patients. All studies were included in the meta-analysis. No significant differences were found regarding the rate of FLR hypertrophy (PVE 43.2%, PVL 38.5%, p = 0.39). The number of cancelled hepatic resections due to inadequate hypertrophy was significantly lower after PVL (p = 0.002). No differences were found in post-intervention mortality and morbidity. This meta-analysis demonstrated no significant differences in safety and rate of FLR hypertrophy between PVE and PVL. PVE should be considered as the preferred strategy, since it is a minimally invasive procedure. However, during a two-stage procedure, PVL can be performed with expected comparable outcome as PVE.

Liver metastases from gastric carcinoma: A Case report and review of the literature

Gastric carcinoma (GC) is the fifth most common malignancy worldwide but the third leading cause of cancer death, and surgery remains the only curative treatment option. Prognosis of patients with liver metastases from gastric carcinoma (LMGC) is poor, and the optimal treatment of metastatic gastric cancer remains a matter of debate. In 2002, a 53-year-old male patient with GC and synchronous oligometastatic lesion in liver VIII segment underwent a total gastrectomy combined with metastasectomy. The pathologic diagnosis was stage IV gastric adenocarcinoma (pT3N2M1), which was treated with adjuvant chemotherapy (cisplatin, epirubicin, leucovorin, and 5-fluorouracil). In 2012, abdominal ultrasound and percutaneous liver biopsy revealed recurrence of the metastasis in the right liver lobe. Progression of the disease was observed after palliative chemotherapy (epirubicin, oxaliplatin, and capecitabine). Nevertheless, an extended right hemihepatectomy, with excision of segments 1, 4A, 5, 6, 7, and 8, was still performed. Pathologic examination confirmed large KRAS- and HER2-negative LMGC. The patient is alive and free of disease 47 months after the repeated hepatectomy and 13 years after removal of the primary GC and synchronous liver metastasis. Based on review of 27 articles, 5-year overall survival rate following gastrectomy and liver metastasectomy may reach 60%, with median survival time up to 74 months. Although the combination of aggressive surgical approach with systemic therapy for LMGC is controversial, it may allow favorable outcome. Careful selection of patients based on evaluable predictive factors for R0 surgical resection of both primary tumor and liver metastases can lead to cure, as shown in our case presentation, where a 10-year relapse-free survival was observed, followed by successful repeated hepatectomy due to liver metastases.

Gd-EOB-DTPA based magnetic resonance imaging for predicting liver response to portal vein embolization

AIM

To evaluate the correlation between degree of kinetic growth (kGR) of the liver following portal vein embolization (PVE) liver and the enhancement of the during the hepatobiliary phase of contrast administration and to evaluate if the enhancement can be used to predict response to PVE prior to the procedure.

METHODS

Seventeen patients were consented for the prospective study. All patients had an MR of the abdomen with Gd-EOB-DTPA. Fourteen patients underwent PVE. The correlation between the kGR of the liver and the degree of enhancement was evaluated with linear regression (strong assumptions) and Spearman’s correlation test (rank based, no assumptions). The correlation was examined for the whole liver, segments I, VIII, VII, VI, V, IV, right liver and left liver.

RESULTS

There was no correlation between the degree of enhancement during the hepatobiliary phase and kGR for any segment, lobe of the liver or whole liver (P = 0.19 to 0.91 by Spearman’s correlation test).

CONCLUSION

The relative enhancement of the liver during the hepatobiliary phase with Gd-EOB-DTPA cannot be used to predict the liver response to PVE.

Ablative Liver Partition and Portal Vein Embolization: Proof-of-Concept Testing in a Rabbit Model

PURPOSE

To test the hypothesis that a modified approach to portal vein embolization (PVE)-termed ablative liver partition (ALP) and PVE (ALP-PVE)-is feasible and results in greater future liver remnant (FLR) growth compared with PVE alone in a rabbit model.

MATERIALS AND METHODS

Eighteen rabbits (median weight, 2.7 kg) underwent PVE (n = 9) or ALP-PVE (n = 9). PVE to cranial liver lobes was performed with 100-300-μm microspheres and metallic coils; the caudal lobe was spared as the FLR. In the ALP-PVE cohort, a liver partition between cranial and caudal lobes was created by using microwave ablation (40 W, 1 min). Animals were euthanized and livers were harvested on postprocedure day 7. Caudal and cranial liver lobes were weighed after 4 weeks of oven drying. Ki-67 immunohistochemistry was used to quantify liver mitotic index. ALP-PVE feasibility was determined based on procedure technical success. Standardized FLR (sFLR; ie, FLR divided by whole liver weight) and mitotic index were compared between PVE and ALP-PVE groups by two-tailed independent-samples Mann-Whitney U test.

RESULTS

One PVE-group rabbit died during anesthesia induction and was excluded from technical success calculation. Eight of 8 (100%) and 8 of 9 rabbits (89%) underwent technically successful PVE and ALP-PVE, respectively. There was no difference in sex or weight distribution between groups. sFLR (0.32 vs 0.29; P = .022) and mitotic index (17.5% vs 6.2%; P = .051) were higher in ALP-PVE vs PVE caudal lobes when the first "learning-curve" case from each group was excluded.

CONCLUSIONS

ALP-PVE is feasible and may stimulate greater FLR growth compared with PVE in a rabbit model.

ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) does not affect proliferation, apoptosis, or angiogenesis as compared to standard liver resection for colorectal liver metastases

Background

ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) is a novel two-stage strategy to induce rapid hypertrophy of the future liver remnant (FLR) when patients are in danger of postoperative liver failure due to insufficient FLR. However, the effects of ALPPS on colorectal liver metastases (CRLM) are not clear so far. The aim of our study was to determine whether ALPPS induces proliferation, apoptosis, or vascularization compared to standard (one-stage) liver resection.

Methods

Six patients who underwent ALPPS were matched with 12 patients undergoing standard liver resection regarding characteristics of the metastases (size, number), time of appearance (syn-/metachronous), preoperative chemotherapy, primary tumor (localization, TNM stage, grading), and patient variables (gender, age). The largest resected metastasis was used for the analyses. Tissue was stained for tumor cell proliferation (Ki67), apoptosis (TUNEL, caspase-3), vascularization (CD31), and pericytes (αSMA).

Results

Vascularization (CD31; p = 0.149), proliferation (Mib-1; p = 0.244), and αSMA expression (p = 0.205) did not significantly differ between the two groups, although a trend towards less proliferation and αSMA expression was observed in patients undergoing ALPPS. Concerning apoptosis, caspase-3 staining showed significantly fewer apoptotic cells upon ALPPS (p < 0.0001), but this was not confirmed by TUNEL staining (p = 0.7344).

Conclusions

ALPPS does not induce proliferation, apoptosis, or vascularization of CRLM when compared to standard liver resection.

Hammer versus Swiss Army knife: Developing a strategy for the management of bilobar colorectal liver metastases

For patients with bilobar colorectal liver metastases, the recent increase in surgical approaches has resulted in more opportunities to extend the benefits of surgery to patients who were previously deemed unresectable. Surgical options now include anatomic hepatectomy, 1-stage parenchymal sparing hepatectomy, traditional 2-stage hepatectomy with or without portal vein embolization, associated liver partition and portal vein ligation for staged hepatectomy, local ablative techniques, and hepatic arterial infusion therapy. As the diversity of options has increased, controversy has arisen as to the optimal operative management of patients with complex bilateral disease. Moreover, there has been a tendency for various surgeons and groups to champion a single strategy. In contrast to this trend, this article introduces a novel "tailored approach" that takes advantage of all available tools and individually applies them based on an algorithmic assessment of the extent and distribution of metastatic disease.

Transition from open to laparoscopic ALPPS for patients with very small FLR: the initial experience

BACKGROUND

Laparoscopic ALPPS (Associating Liver Partition and Portal vein ligation for Staged hepatectomy) has previously been reported but has been the authors' default option since 2015 in patients with small future liver remnant.

METHODS

A retrospective analysis of all consecutive patients undergoing ALPPS at a single referral center was performed using a prospective database from July 2011 to June 2016. Feasibility was studied by assessing conversions. The 90-day mortality and complications were analyzed using a Dindo-Clavien score and the comprehensive complication index. Operative time, blood loss, volumetric growth, and hospital stay were examined. The CUSUM analysis was performed.

RESULTS

ALPPS was performed in 30 patients, 10 of whom underwent a laparoscopic approach. There was no mortality and no complication grade ≥3A observed in laparoscopic ALPPS. In open ALPPS, 10 of 20 patients experienced complications grade ≥3A (p = 0.006) and one patient died. Liver failure was not observed after laparoscopic ALPPS, but two patients in the open ALPPS group developed complications that precluded the second stage. The total hospital stay was shorter in the laparoscopic ALPPS group.

CONCLUSION

Laparoscopic ALPPS is feasible as the default procedure for patients with very small FLR, and it is not inferior to the open approach. Surgeons experienced with complex laparoscopy should be encouraged to use a laparoscopic approach to ALPPS.

[Comparative analysis of static scintigraphy and computerized tomography in assessment of remnant liver volume after advanced hepatic resection]

AIM

To perform a comparative analysis of computerized tomographic volumetry and scintigraphic liver volumetry in assessment of remnant liver volume after advanced hepatic resection.

MATERIAL AND METHODS

Static hepatobiliary scintigraphy and CT volumetry were performed in 45 patients with various liver tumors who underwent advanced hepatectomies (more than three segments).

RESULTS

There were no any significant differences in volumetric parameters obtained by CT and scintigraphic volumetry.

CONCLUSION

Scintigraphic volumetry data are similar to those of CT volumetry in evaluation of future remnant liver volume. Scintigraphic volumetry may be used as an alternative in assessment of future remnant liver volume after advanced hepatic resections.

Dynamic Evaluation of Liver Volume and Function in Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy

BACKGROUND

Despite a fast and potent growth of the future liver remnant (FLR), patients operated with associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) are at risk of developing posthepatectomy liver failure. In this study, the relation between liver volume and function in ALPPS was studied using a multimodal assessment.

METHODS

Nine patients with colorectal liver metastases treated with neoadjuvant chemotherapy and operated with ALPPS were studied with hepatobiliary scintigraphy, computed tomography, indocyanine green clearance test, and serum liver function tests. A comparison between liver volume and function was conducted.

RESULTS

The preoperative FLR volume of 19.5% underestimated the preoperative FLR function of 25.3% (p = 0.011). The increase in FLR volume exceeded the increase in function at day 6 after stage 1 (FLR volume increase 56.7% versus FLR function increase 28.2%, p = 0.021), meaning that the increase in function was 50% of the increase in volume. After stage 2, functional increase exceeded the volume increase, resulting in similar values 28 days after stage 2.

CONCLUSIONS

In the inter-stage period of ALPPS, the high volume increase is not paralleled by a corresponding functional increase. This may in part explain the high morbidity and mortality rates associated with ALPPS. Functional assessment of the FLR is advised.

Identification of cofactors influencing hypertrophy of the future liver remnant after portal vein embolization-the effect of collaterals on embolized liver volume

OBJECTIVE

The purpose of this retrospective study was to monitor hypertrophy of future liver remnant following portal vein embolization (PVE) before planned extended right hepatectomy. However, because individual responses to PVE are highly variable, our focus was to identify cofactors of successful hypertrophy.

METHODS

28 patients with primary or secondary liver tumours, mean age 64.1 ± 12.9 years, underwent PVE. Volumetric analysis of hypertrophy before and after PVE (median 39.0 ± 15.7 days) was performed. The embolized liver segments were investigated for occurrence of reperfusion of their portal branches. Blood parameters before PVE were additionally investigated.

RESULTS

Patients were divided into responders (21/28) and non-responders (7/28) by post-PVE standardized future liver remnant being above or below 25%, respectively. No significant differences between the groups were found regarding biometric and volumetric parameters before PVE. In the entire group after PVE, the mean absolute increase of Segments 2 and 3 was 196.0 ± 84.7 cm³ and the median relative increase was 46.6 ± 98.8%. The formation of left to right hepatic portoportal collaterals exhibited a negative correlation to successful hypertrophy (p = 0.004) as well as low plasma total protein (p = 0.019). Successful embolization of Segment IV showed only a trend to significance (p = 0.098).

CONCLUSION

Cofactors associated with a favourable outcome regarding hypertrophy were the absence of collaterals in the control CT scans and high plasma total protein. Advances in knowledge: Portoportal collaterals negatively influence hypertrophy after PVE. On the other hand, plasma total protein is a positive prognostic indicator on hypertrophy of the liver in our cohort.

Liver kinetic growth rate predicts postoperative liver failure after ALPPS

BACKGROUND

Posthepatectomy liver failure (PHLF) may occur after ALPPS (Associating liver partition and portal vein ligation for staged hepatectomy) despite a sufficient standardized future liver remnant (sFLR) volume. The aim of this study was to test kinetic growth rate (KGR) after ALPPS stage 1, describing the percentage increase of sFLR per day, as a predictor of PHLF after completion of ALPPS.

METHODS

The ability of KGR to predict PHLF after ALPPS stage 2 was investigated in 38 patients. PHLF was defined according to the "50-50" and ISGLS criteria.

RESULTS

Completion of ALPPS was achieved in 95% (36/38) of patients. The incidence of PHLF was 22% (8/36) and 36% (13/36) according to "50-50" and ISGLS criteria, respectively. Whereas a sFLR cut off at 30% alone failed to predict PHLF, KGR ≥6%/day after stage 1 was associated with a significant reduced risk of PHLF ("50-50", p = 0.03/ISGLS, p = 0.03) after stage 2. Adherence to both concomitant KGR ≥6%/day and sFLR ≥30% reduced the incidence of PHLF to 0%.

CONCLUSIONS

Assessment of KGR is a novel tool to estimate the risk of PHLF after ALPPS. Respecting KGR and sFLR after ALPPS stage 1 may increase safety in patients undergoing ALPPS.

Meta-analysis of associating liver partition with portal vein ligation and portal vein occlusion for two-stage hepatectomy

BACKGROUND

Discussion is ongoing regarding whether associating liver partition with portal vein ligation for staged hepatectomy (ALPPS) or portal vein occlusion is better in staged hepatectomy. The aim of this study was to compare available strategies using a two-stage approach in extended hepatectomy.

METHODS

A literature search was performed in MEDLINE, Scopus, the Cochrane Library and Embase, and additional articles were identified by hand searching. Data from the international ALPPS registry were extracted. Clinical studies reporting volumetric changes, mortality, morbidity, feasibility of the second stage and tumour-free resection margins (R0) in two-stage hepatectomy were included.

RESULTS

Ninety studies involving 4352 patients, including 320 from the ALPPS registry, met the inclusion criteria. Among these, nine studies (357 patients) reported on comparisons with other strategies. In the comparison of ALPPS versus portal vein embolization (PVE), ALPPS was associated with a greater increase in the future liver remnant (76 versus 37 per cent; P < 0·001) and more frequent completion of stage 2 (100 versus 77 per cent; P < 0·001). Compared with PVE, ALPPS had a trend towards higher morbidity (73 versus 59 per cent; P = 0·16) and mortality (14 versus 7 per cent; P = 0·19) after stage 2. In the non-comparative studies, complication rates were 39 per cent in the PVE group, 47 per cent in the portal vein ligation (PVL) group and 70 per cent in the ALPPS group. After stage 2, mortality rates were 5, 7 and 12 per cent respectively.

CONCLUSION

ALPPS is associated with greater future liver remnant hypertrophy and a higher rate of completion of stage 2, but this may be at the price of greater morbidity and mortality.

The Future Liver Remnant in Patients Undergoing the Associating Liver Partition with Portal Vein Ligation for Staged Hepatectomy (ALPPS) Maintains the Immunological Components of a Healthy Organ

Background and Aims

A short-interval, two-stage approach termed associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) increases the number of patients with extensive malignant disease of the liver and a small future liver remnant (FLR) that can undergo liver resection. While this approach results in accelerated liver hypertrophy of the FLR, it remains unknown whether this phenomenon is restricted to liver parenchymal cells. In the current study, we evaluated whether ALPPS alters the immunological composition of the deportalized lobe (DL) and the FLR.

Methods

In this prospective, single-center study, liver tissue from the DL and the FLR were collected intra-operatively from adult patients undergoing ALPPS for their liver metastases. The extent of hypertrophy of the FLR was determined by volumetric helical computed tomography. Flow cytometry and histological analyses were conducted on liver tissues to compare the frequency of several immune cell subsets, and the architecture of the liver parenchyma between both stages of ALPPS.

Results

A total of 12 patients completed the study. Histologically, we observed a patchy peri-portal infiltration of lymphocytes within the DL, and a significant widening of the liver cords within the FLR. Within the DL, there was a significantly higher proportion of B cells and CD4⁺ T cells as well innate-like lymphocytes, namely mucosa-associated invariant T (MAIT) cells and natural killer T (NKT) cells following ALPPS. In contrast, the frequency of all evaluated immune cell types remained relatively constant in the FLR.

Conclusion

Our results provide the first description of the immunological composition of the human liver following ALPPS. We show that following the ALPPS procedure, while the immune composition of the FLR remains relatively unchanged, there is a moderate increase in several immune cell populations in DL. Overall, our results support the continued utilization of the ALPPS procedure.

Size mismatch in liver transplantation

Size mismatch is an unique and inevitable but critical issue in live donor liver transplantation. Unmatched metabolic demand of recipient as well as physiologic mismatch aggravates the damage to liver graft, inevitably leading to graft failure on recipient. Also, an excessive resection of liver graft for better recipient outcome in live donor liver transplant may jeopardize the healthy donor well-being and even put donor life in danger. There is a fine balance between resected graft volume required to meet the recipient's metabolic demand and residual graft volume required for donor safety. The obvious clinical necessity of finding that balance has prompted a clinical need and promoted the improvement of knowledge and development of management strategies for size-mismatched transplants. The development of the size-matching methodology has significantly improved graft outcome and recipient survival in live donor liver transplants. On the other hand, the effect of size mismatch in cadaveric transplants has never been observed as being so pronounced. The importance of matching of the donor recipient size has been unrecognized in cadaveric liver transplant. In this review, we attempt to summarize the current most updated knowledge on the subject, particularly addressing the definition and complications of size-mismatched cadaveric liver transplant, as well as management strategies.

Small for Size and Flow (SFSF) syndrome: An alternative description for posthepatectomy liver failure

Small for Size Syndrome (SFSS) syndrome is a recognizable clinical syndrome occurring in the presence of a reduced mass of liver, which is insufficient to maintain normal liver function. A definition has yet to be fully clarified, but it is a common clinical syndrome following partial liver transplantation and extended hepatectomy, which is characterized by postoperative liver dysfunction with prolonged cholestasis and coagulopathy, portal hypertension, and ascites. So far, this syndrome has been discussed with focus on the remnant size of the liver after partial liver transplantation or extended hepatectomy. However, the current viewpoints believe that the excessive flow of portal vein for the volume of the liver parenchyma leads to over-pressure, sinusoidal endothelial damages and haemorrhage. The new hypothesis declares that in both extended hepatectomy and partial liver transplantation, progression of Small for Size Syndrome is not determined only by the "size" of the liver graft or remnant, but by the hemodynamic parameters of the hepatic circulation, especially portal vein flow. Therefore, we suggest the term "Small for Size and Flow (SFSF)" for this syndrome. We believe that it is important for liver surgeons to know the pathogenesis and manifestation of this syndrome to react early enough preventing non-reversible tissue damages.

Portal Venous Interventions: State of the Art

In recent decades, there have been numerous advances in the management of liver cancer, cirrhosis, and diabetes mellitus. Although these diseases are wide ranging in their clinical manifestations, each can potentially be treated by exploiting the blood flow dynamics within the portal venous system, and in some cases, adding cellular therapies. To aid in the management of these disease states, minimally invasive transcatheter portal venous interventions have been developed to improve the safety of major hepatic resection, to reduce the untoward effects of sequelae from end-stage liver disease, and to minimize the requirement of exogenously administered insulin for patients with diabetes mellitus. This state of the art review therefore provides an overview of the most recent data and strategies for utilization of preoperative portal vein embolization, transjugular intrahepatic portosystemic shunt placement, balloon retrograde transvenous obliteration, and islet cell transplantation.

Disposable bipolar irrigated sealer (Aquamantys(®)) for liver resection: use with caution

The disposable bipolar irrigated sealer has been demonstrated to reduce perioperative bleeding, but its role in preventing postoperative cut-surface complications has not been evaluated to date. A prospective observational study was performed between January and September 2013 to evaluate a disposable bipolar irrigated sealed (Aquamantys(®)) on a continuous series of 51 first liver resections without biliary reconstruction. Primary end-point was the occurrence of cut-surface complications during the postoperative period. Secondary endpoints were postoperative complications and the 1-year overall survival rate. The results were compared to a propensity score matched group of 153 liver resections performed with conventional monopolar cautery. A cut-surface complication occurred in 13/51 (25.5 %) resected patients. Bleeding, bile leakage and subphrenic abscess occurred in 7.8, 11.8 and 11.8 % patients, respectively. Compared to the matched group, the resected group had a higher rate of cut-surface complications (25.5 vs. 14.7 %, p < 0.01) and a higher rate of Clavien-Dindo type ≥3 postoperative complications (29.5 vs. 17.2 %, p < 0.01). In the multivariate analysis, preoperative chemotherapy (p = 0.03, 95 % CI 1.09-5.9, OR 2.53), blood transfusion (p = 0.02, 95 % CI 1.78-6.55, OR 2.78) and Aquamantys(®) use (p = 0.02, 95 % CI 1.21-6.7, OR 2.85) were independent of cut-surface complications within the first 90 postoperative days. The overall 1-year survival rates were not different between the two groups (p = 0.078). Aquamantys(®) use is associated with an increased rate of postoperative complications compared to classical monopolar cautery, and we recommend that it should be used with caution in this type of surgery.

Significance of functional hepatic resection rate calculated using 3D CT/(99m)Tc-galactosyl human serum albumin single-photon emission computed tomography fusion imaging

AIM

To evaluate the usefulness of the functional hepatic resection rate (FHRR) calculated using 3D computed tomography (CT)/(99m)Tc-galactosyl-human serum albumin (GSA) single-photon emission computed tomography (SPECT) fusion imaging for surgical decision making.

METHODS

We enrolled 57 patients who underwent bi- or trisectionectomy at our institution between October 2013 and March 2015. Of these, 26 patients presented with hepatocellular carcinoma, 12 with hilar cholangiocarcinoma, six with intrahepatic cholangiocarcinoma, four with liver metastasis, and nine with other diseases. All patients preoperatively underwent three-phase dynamic multidetector CT and (99m)Tc-GSA scintigraphy. We compared the parenchymal hepatic resection rate (PHRR) with the FHRR, which was defined as the resection volume counts per total liver volume counts on 3D CT/(99m)Tc-GSA SPECT fusion images.

RESULTS

In total, 50 patients underwent bisectionectomy and seven underwent trisectionectomy. Biliary reconstruction was performed in 15 patients, including hepatopancreatoduodenectomy in two. FHRR and PHRR were 38.6 ± 19.9 and 44.5 ± 16.0, respectively; FHRR was strongly correlated with PHRR. The regression coefficient for FHRR on PHRR was 1.16 (P < 0.0001). The ratio of FHRR to PHRR for patients with preoperative therapies (transcatheter arterial chemoembolization, radiation, radiofrequency ablation, etc.), large tumors with a volume of > 1000 mL, and/or macroscopic vascular invasion was significantly smaller than that for patients without these factors (0.73 ± 0.19 vs 0.82 ± 0.18, P < 0.05). Postoperative hyperbilirubinemia was observed in six patients. Major morbidities (Clavien-Dindo grade ≥ 3) occurred in 17 patients (29.8%). There was no case of surgery-related death.

CONCLUSION

Our results suggest that FHRR is an important deciding factor for major hepatectomy, because FHRR and PHRR may be discrepant owing to insufficient hepatic inflow and congestion in patients with preoperative therapies, macroscopic vascular invasion, and/or a tumor volume of > 1000 mL.

Postoperative Mortality after Liver Resection for Perihilar Cholangiocarcinoma: Development of a Risk Score and Importance of Biliary Drainage of the Future Liver Remnant

BACKGROUND

Liver surgery for perihilar cholangiocarcinoma (PHC) is associated with postoperative mortality ranging from 5% to 18%. The aim of this study was to develop a preoperative risk score for postoperative mortality after liver resection for PHC, and to assess the effect of biliary drainage of the future liver remnant (FLR).

STUDY DESIGN

A consecutive series of 287 patients submitted to major liver resection for presumed PHC between 1997 and 2014 at 2 Western centers was analyzed; 228 patients (79%) underwent preoperative drainage for jaundice. Future liver remnant volumes were calculated with CT volumetry and completeness of FLR drainage was assessed on imaging. Logistic regression was used to develop a mortality risk score.

RESULTS

Postoperative mortality at 90 days was 14% and was independently predicted by age (odds ratio [OR] per 10 years = 2.1), preoperative cholangitis (OR = 4.1), FLR volume <30% (OR = 2.9), portal vein reconstruction (OR = 2.3), and incomplete FLR drainage in patients with FLR volume <50% (OR = 2.8). The risk score showed good discrimination (area under the curve = 0.75 after bootstrap validation) and ranking patients in tertiles identified 3 (ie low, intermediate, and high) risk subgroups with predicted mortalities of 2%, 11%, and 37%. No postoperative mortality was observed in 33 undrained patients with FLR volumes >50%, including 10 jaundiced patients (median bilirubin level 11 mg/dL).

CONCLUSIONS

The mortality risk score for patients with resectable PHC can be used for patient counseling and identification of modifiable risk factors, which include FLR volume, FLR drainage status, and preoperative cholangitis. We found no evidence to support preoperative biliary drainage in patients with an FLR volume >50%.

Evaluating the Clinical Applicability of the European Staging System for Perihilar Cholangiocarcinoma

BACKGROUND

In 2011, a new European Staging System (ESS) for perihilar cholangiocarcinoma (PHC) was proposed with the expressed purpose of comparing treatment and outcomes data between institutions. The goal of this study was to evaluate the feasibility of ESS data capture.

STUDY DESIGN

Forty-seven consecutive patients who underwent surgical resection for PHC between 1999 and 2013 were studied. Demographic variables, components of various staging systems (including the ESS), preoperative and perioperative details, pathology, and outcomes were recorded.

RESULTS

The mean patient age was 63.2 and 62% were male. Preoperative imaging included high-resolution CT in all patients, MRI in 34%, and PET in 11%. R0 resection was accomplished in 80% of patients. Four patients (8.5%) and 18 patients (38.3%), respectively, received neoadjuvant or adjuvant therapy. During a mean follow-up of 36 months, recurrence rate was 51.3% and 2- and 5-year survival rates were 69.4 and 33.3%, respectively. Analysis of data capture found that tumor (T) classification was indeterminable in 7/47 patients (14.9%). For two patients, the form (F) designation had insufficient data. The extent of vascular involvement (PV/HA) was different compared to preoperative imaging in nine patients (19.1%). The liver remnant volume (V) was calculated in only 18 patients (38.3%). The liver disease (D) variable did not account for four patients with inflammation/cirrhosis. In total, only 15 patients (31.9%) had all required elements to complete the ESS.

CONCLUSIONS

Without templated radiology, surgery, and pathology reports, the ESS cannot be applied to current clinical/research practice. Although resection continues to provide significant survival benefit to patients with perihilar cholangiocarcinoma, lack of an accurate prognostic tool for resectability and outcomes continues to be a major impediment to progress in the field.

RAS Mutation Predicts Positive Resection Margins and Narrower Resection Margins in Patients Undergoing Resection of Colorectal Liver Metastases

BACKGROUND

In patients undergoing resection of colorectal liver metastases (CLM), resection margin status is a significant predictor of survival, particularly in patients with suboptimal response to preoperative therapy. RAS mutations have been linked to more invasive and migratory tumor biology and poor response to modern chemotherapy.

OBJECTIVE

The aim of this study was to evaluate the relationship between RAS mutation and resection margin status in patients undergoing resection of CLM.

METHODS

Patients who underwent curative resection of CLM from 2005 to 2013 with known RAS mutation status were identified from a prospectively maintained database. A positive margin was defined as tumor cells <1 mm from the parenchymal transection line.

RESULTS

The study included 633 patients, of whom 229 (36.2 %) had mutant RAS. The positive margin rate was 11.4 % (26/229) for mutant RAS and 5.4 % (22/404) for wild-type RAS (p = 0.007). In multivariate analysis, the only factors associated with a positive margin were RAS mutation (hazard ratio [HR] 2.439; p = 0.005) and carcinoembryonic antigen level 4.5 ng/mL or greater (HR 2.060; p = 0.026). Among patients presenting with liver-first recurrence during follow-up, those with mutant RAS had narrower margins at initial CLM resection (median 4 mm vs. 7 mm; p = 0.031). A positive margin (HR 3.360; p < 0.001) and RAS mutation (HR 1.629; p = 0.044) were independently associated with worse overall survival.

CONCLUSION

RAS mutations are associated with positive margins in patients undergoing resection of CLM. Tumors with RAS mutation should prompt careful efforts to achieve negative resection margins.

Clinical Significance of Spleen-Remnant Liver Volume Ratio in Hepatocellular Carcinoma Surgery

The objective of this study was to explore the value of spleen-remnant liver volume ratio for hepatocellular carcinoma surgery and liver reserve assessment. Spleen-remnant liver volume ratio postoperation was measured with imageological methods and water displacement, and the liver function postoperation and hospital stay of patients with different spleen-remnant liver volume ratios were compared. Spleen-remnant liver volume ratio was closely related to liver function assessment postoperation. The higher the ratio, the higher the assessment score of liver function postoperation would be. When spleen-remnant liver volume ratio was ≤0.9, the patients had a fast recovery and short hospital stay. Spleen-remnant liver volume ratio can effectively predict the recovery and liver reserve of patients with hepatocellular carcinoma postoperation. When postoperative spleen-remnant liver volume ratio is predicted to be ≤0.9, the operation can be performed; and when the ratio is predicted to be ≥1.2, the operation is not suggested.