Novel virtual hepatectomy is useful for evaluation of the portal territory for anatomical sectionectomy, segmentectomy, and hemihepatectomy

Anatomical Quantitative Volumetric Evaluation of Liver Segments in Hepatocellular Carcinoma Patients Treated with Selective Internal Radiation Therapy: Key Parameters Influencing Untreated Liver Hypertrophy

Background: Factors affecting morphological changes in the liver following selective internal radiation therapy (SIRT) are unclear, and the available literature focuses on non-anatomical volumetric assessment techniques in a lobar treatment setting. This study aimed to investigate quantitative changes in the liver post-SIRT using an anatomical volumetric approach in hepatocellular carcinoma (HCC) patients with different levels of treatment selectivity and evaluate the parameters affecting those changes. This retrospective, single-institution, IRB-approved study included 88 HCC patients. Whole liver, liver segments, tumor burden, and spleen volumes were quantified on MRI at baseline and 3/6/12 months post-SIRT using a segmentation-based 3D software relying on liver vascular anatomy. Treatment characteristics, longitudinal clinical/laboratory, and imaging data were analyzed. The Student's t-test and Wilcoxon test evaluated volumetric parameters evolution. Spearman correlation was used to assess the association between variables. Uni/multivariate analyses investigated factors influencing untreated liver volume (uLV) increase. Results: Most patients were cirrhotic (92%) men (86%) with Child-Pugh A (84%). Absolute and relative uLV kept increasing at 3/6/12 months post-SIRT vs. baseline (all, p ≤ 0.005) and was maximal during the first 6 months. Absolute uLV increase was greater in Child-Pugh A5/A6 vs. ≥B7 at 3 months (A5, p = 0.004; A6, p = 0.007) and 6 months (A5, p = 0.072; A6, p = 0.031) vs. baseline. When the Child-Pugh class worsened at 3 or 6 months post-SIRT, uLV did not change significantly, whereas it increased at 3/6/12 months vs. baseline (all p ≤ 0.015) when liver function remained stable. The Child-Pugh score was inversely correlated with absolute and relative uLV increase at 3 months (rho = -0.21, p = 0.047; rho = -0.229, p = 0.048). In multivariate analysis, uLV increase was influenced at 3 months by younger age (p = 0.013), administered 90Y activity (p = 0.003), and baseline spleen volume (p = 0.023). At 6 months, uLV increase was impacted by younger age (p = 0.006), whereas treatment with glass microspheres (vs. resin) demonstrated a clear trend towards better hypertrophy (f = 3.833, p = 0.058). The amount (percentage) of treated liver strongly impacted the relative uLV increase at 3/6/12 months (all f ≥ 8.407, p ≤ 0.01). Conclusion: Liver function (preserved baseline and stable post-SIRT) favored uLV hypertrophy. Younger patients, smaller baseline spleen volume, higher administered 90Y activity, and a larger amount of treated liver were associated with a higher degree of untreated liver hypertrophy. These factors should be considered in surgical candidates undergoing neoadjuvant SIRT.

Uses of a dedicated 3D reconstruction software with augmented and mixed reality in planning and performing advanced liver surgery and living donor liver transplantation (with videos)

The development of digital intelligent diagnostic and treatment technology has opened countless new opportunities for liver surgery from the era of digital anatomy to a new era of digital diagnostics, virtual surgery simulation and using the created scenarios in real-time surgery using mixed reality. In this article, we described our experience on developing a dedicated 3 dimensional visualization and reconstruction software for surgeons to be used in advanced liver surgery and living donor liver transplantation. Furthermore, we shared the recent developments in the field by explaining the outreach of the software from virtual reality to augmented reality and mixed reality.

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

BACKGROUND

In preparation for the upcoming consensus meeting in Tokyo in 2021, this systematic review aimed to analyze the current available evidence regarding surgical anatomy of the liver, focusing on useful landmarks, strategies and technical tools to perform precise anatomic liver resection (ALR).

METHODS

A systematic review was conducted on MEDLINE/PubMed for English articles and on Ichushi database for Japanese articles until September 2020. The quality assessment of the articles was performed in accordance with the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

A total of 3169 manuscripts were obtained, 1993 in English and 1176 in Japanese literature. Subsequently, 63 English and 20 Japanese articles were selected and reviewed. The quality assessment of comparative series and case series was revealed to be usually low; only six articles were qualified as high quality. Forty-two articles focused on analyzing intersegmental/sectional planes and their relationship with specific hepatic landmark veins. In 12 articles, the authors aimed to investigate liver surface anatomic structures, while 36 articles aimed to study technological tools and contrast agents for surgical segmentation during ALR. Although Couinaud's classification has remained the cornerstone in daily diagnostic/surgical practices, it does not always portray the realistic liver segmentation and there has been no standardization on which a single strategy should be followed to perform precise ALR.

CONCLUSIONS

A global consensus should be pursued in order to establish clear guidelines and proper recommendations to perform ALR in the era of minimally invasive surgery.

Image guidance using two-dimensional illustrations and three-dimensional modeling of donor anatomy during living donor hepatectomy

BACKGROUND

For living donor liver transplantation, preoperative imaging is required for the safety of both the donor and the recipient. We previously initiated our image-guidance program using two-dimensional illustrations and three-dimensional modeling in September 2018; herein, we analyzed the resultant changes in the clinical outcomes.

METHODS

Living donors and recipients who underwent liver transplantation between September 2017 and August 2019 were included. Cases with image guidance were compared to those without image guidance regarding the operative outcome, especially bile-duct opening in the graft as well as surgical complications.

RESULTS

Among 200 living donor transplantation, 90 transplantations were completed with image guidance. The image-guidance group had a higher rate of laparoscopy (80.9% vs. 97.8%; p < .001) as compared with the group without image guidance. Although there was no difference in the type of bile duct (p = .144), more grafts with single bile-duct openings were found in the image-guidance group (52.7% vs. 80.0%; p = .001). Consequently, achievements in bile-duct openings were superior in the image-guidance group (p = .022). There were no differences in bile leakage, graft failure, or number of deaths during the first month post-transplantation.

CONCLUSION

As we initiated our image-guidance program for living donor liver transplantation, clinical outcomes, especially bile-duct division, were improved relative to before implementation.

Hepatocellular carcinoma with a non-smooth tumor margin on hepatobiliary-phase gadoxetic acid disodium-enhanced magnetic resonance imaging. Is sectionectomy the suitable treatment?

BACKGROUND/PURPOSE

Anatomical sectionectomy or larger resection is known to be effective in patients with hepatocellular carcinoma (HCC) with microvascular invasion. A non-smooth tumor margin on hepatobiliary-phase gadoxetic acid disodium-enhanced magnetic resonance imaging (EOB-MRI) can predict microvascular invasion of HCC. We evaluated the usefulness of EOB-MRI for operative planning.

METHODS

We evaluated 224 patients with single HCC who underwent hepatectomy between 2010 and 2013. The tumor margin was determined preoperatively. The hepatic resection was determined based on tumor location, liver function, 3D CT simulation and functional liver reserve. To control for confounding variable distributions, propensity score match was applied to compare the outcomes. Multivariate analysis was conducted to identify independent predictors of 5-year recurrence-free survival (RFS) and overall survival (OS).

RESULTS

Of 113 patients with a non-smooth tumor margin, 40 patients (35%) showed microscopic portal invasion. The 5-year RFS and OS rates were significantly higher after sectionectomy or larger hepatectomy (hemihepatectomy) than after segmentectomy or smaller hepatectomy (non-anatomical resection). Of 111 patients with a smooth tumor margin, eight patients (7%) showed microscopic portal invasion. The 5-year RFS and OS rates did not differ significantly between patients who underwent sectionectomy and those who underwent segmentectomy.

CONCLUSIONS

Our preliminary results appear to recommend that HCC with a non-smooth margin on HB-phase images is treated with anatomical sectionectomy or larger hepatectomy.

Description of the Vascular Anatomy of Livers with Absence of the Portal Bifurcation

BACKGROUND

The absence of the portal bifurcation (APB) is a rare anatomic variation, in which the horizontal part of the left portal vein (PV) is missing. The aim of this study was to identify the vascular architecture in livers with APB.

METHODS

Computed tomography data for 17,651 patients were reviewed; five patients (0.03%) were found to present with APB. The liver volume and anatomy of APB patients were compared with those of 30 patients with normal livers.

RESULTS

All the APB patients exhibited an independent posterior branch of the PV. The intrahepatic left PV (LPV) ran through either the ventral (n = 2, 40%) or dorsal side (n = 3, 60%) of the middle hepatic vein. The frequency of medial branches diverging from the LPV was higher in patients with APB than in normal patients (p < 0.001). The left hepatic duct (LHD) ran through the inside of the left lobe along the left PV in 40% of the patients with APB, whereas in the remaining 60% of the patients with APB, the LHD ran on the outside of the liver separately from the left PV and joined the right hepatic duct. The liver volume of the left lateral section was significantly smaller (p = 0.014), and the posterior section was significantly larger (p = 0.014) in patients with APB than in patients with normal livers.

CONCLUSION

The unique anatomical characteristics and the positional relation of the vessels should be considered preoperatively in patients with APB.

Simulation and navigation liver surgery: an update after 2,000 virtual hepatectomies

The advent of preoperative 3-dimensional (3D) simulation software has made a variety of unprecedented surgical simulations possible. Since 2004, we have performed more than 2,000 preoperative simulations in the University of Tokyo Hospital, and they have enabled us to obtain a great deal of information, such as the detailed shape of liver segments, the precise volume of each segment, and the volume of hepatic venous drainage areas. As a result, we have been able to perform more aggressive and complicated surgery safely. The next step is to create a navigation system that will accurately reproduce the preoperative plan. Real-time virtual sonography (RVS) is a navigation system that provides fusion images of ultrasonography and reconstructed computed tomography images or magnetic resonance images. The RVS system facilitates the surgeon's understanding of interpretation of ultrasound images and the detection of tumors that are difficult to find by ultrasound alone. In the near future, surgical navigation systems may evolve to the point where they will be able to inform surgeons intraoperatively in real time about not only intrahepatic structures, such as vessels and tumors, but also the portal territory, hepatic vein drainage areas, and resection lines that have been planned preoperatively.

Precise right hemihepatectomy for the treatment of hepatocellular carcinoma guided by fusion ICG fluorescence imaging

To evaluate the clinical significance of fusion indocyanine green (ICG) fluorescence imaging in precise right hemihepatectomy for the treatment of hepatocellular carcinoma (HCC). 47 patients with HCC who underwent right hemihepatectomy were retrospectively analyzed. 18 of them guided by fusion ICG fluorescence imaging (FIGFI) while 29 patients underwent conventional right hepatectomy without guidance. Compared to the patients with conventional treatment, the intraoperative blood loss of the patients with guided surgery was significantly less, and no transfusion and hepatic occlusion were performed during the operation. Liver function recovery faster in guided group. The incidence of postoperative complications is also lower, and the recurrence rate in one year is significantly reduced. ICG fluorescence range of 18 patients in liver surface was consistent with the ischemic line, and their postoperative liver cross-sections were clearly demarcation. There were no significant differences in the mean operation time, blood loss, postoperative hospital stays, cases of blood transfusion, complication rate, or postoperative peak volume of ALT and TB between positive or negative staining groups. Pathology results of all patients demonstrated HCC and negative margins, and microvascular invasion occurred in 8 cases. The average follow-up time of 18 patients was 16.7 months, and recurrence was found in 5 cases after surgery. FIGFI could guide the anatomical right hepatectomy with real -time increased radical rate, accuracy and safety for the treatment of HCC, and therefore showed a promising prospect.

Renal Artery Perfusion Evaluation Before Transplantation via a 3-Dimensional Image Analysis System

Background:

The perfusion areas of renal arteries in renal transplantation are assessed via subjective observations during perfusion in a bench surgery; however, this evaluation method lacks reliability and objectivity. In this study, we aimed to evaluate the perfusion area of each main and side artery kidney graft using a 3-dimensional (3D) image analysis system.

Methods:

We enrolled 50 patients who had undergone living kidney transplantation with multiple renal artery grafting at our center between 2005 and 2017. All computed tomography images from donors were retrospectively analyzed using a 3D image analysis system. We then calculated the artery perfusion areas associated with the artery reconstruction method used.

Results:

The perfusion areas of side arteries, which were evaluated after surgery, were statistically different among cases employing different reconstruction methods (P &lt; 0.001). The perfusion area of the ligated side arteries (volume, 10 mL; proportion, 6.1%) was smaller than that of the ligated side arteries where different reconstruction methods were used.

Conclusion:

A 3D image analysis system could provide an accurate visual representation of the vasculature prior to living donor transplantation. It could also enable calculation of perfusion area for each artery and preoperative prediction of the need for arterial reconstruction, thereby promoting safe kidney transplantation surgery.

Preliminary Kidney Parenchymal Ligation Using Endoloop Ligatures-A Simple Method to Achieve a Trifecta in Laparoscopic Partial Nephrectomy Without Hilar Clamping for Polar Complex Tumors

OBJECTIVE

To describe a novel and simple technique of preliminary kidney parenchymal ligation using Endoloop ligatures during laparoscopic partial nephrectomy (PN) without hilar clamping for polar complex tumor cases.

METHODS

The subjects were 17 patients who had a renal mass with a R.E.N.A.L. nephrometry score ≥7 (7/8/9/10 in 3/6/6/2 patients, respectively) located in the pole of the kidney. Patient-specific 3D reconstructed kidney images were created for preoperative planning in all cases. The renal hilar vessels were meticulously dissected and definitive tumor feeders were sacrificed when the branches directly perfused the peri-tumor area. Following the vascular microdissection, a circumferential cortex-depth incision on the kidney was made all around the tumor. Consequently, several Endoloop ligatures were placed in the incised tumor base to ligate the parenchyma preliminarily. Step-by-step Endoloop tightening facilitated effective parenchymal dissection without the urinary tract. After confirming that the tumor base parenchyma was ligated sufficiently, tumor resection was completed. Neither inner- nor outer-layer renorrhaphy sutures were placed.

RESULTS

Perioperative outcomes were satisfactory and all patients had negative surgical margins with no damage in the tumor capsule. Urological complications and renal function lower than predicted at 3 months after surgery involved 1 and 3 cases, respectively. The rate of PN trifecta achievement was 82% (14/17) despite the complexity of the 17 tumors.

CONCLUSION

The current technique helped surgeons achieve the trifecta in patients with polar complex masses treated with laparoscopic PN. Use of this technique can provide surgeons with a bloodless operative field even during PN without hilar clamping.

Three-Dimensional Liver Surgery Simulation: Computer-Assisted Surgical Planning with Three-Dimensional Simulation Software and Three-Dimensional Printing<sup/>

To perform accurate hepatectomy without injury, it is necessary to understand the anatomical relationship among the branches of Glisson's sheath, hepatic veins, and tumor. In Japan, three-dimensional (3D) preoperative simulation for liver surgery is becoming increasingly common, and liver 3D modeling and 3D hepatectomy simulation by 3D analysis software for liver surgery have been covered by universal healthcare insurance since 2012. Herein, we review the history of virtual hepatectomy using computer-assisted surgery (CAS) and our research to date, and we discuss the future prospects of CAS. We have used the SYNAPSE VINCENT medical imaging system (Fujifilm Medical, Tokyo, Japan) for 3D visualization and virtual resection of the liver since 2010. We developed a novel fusion imaging technique combining 3D computed tomography (CT) with magnetic resonance imaging (MRI). The fusion image enables us to easily visualize anatomic relationships among the hepatic arteries, portal veins, bile duct, and tumor in the hepatic hilum. In 2013, we developed an original software, called Liversim, which enables real-time deformation of the liver using physical simulation, and a randomized control trial has recently been conducted to evaluate the use of Liversim and SYNAPSE VINCENT for preoperative simulation and planning. Furthermore, we developed a novel hollow 3D-printed liver model whose surface is covered with frames. This model is useful for safe liver resection, has better visibility, and the production cost is reduced to one-third of a previous model. Preoperative simulation and navigation with CAS in liver resection are expected to help planning and conducting a surgery and surgical education. Thus, a novel CAS system will contribute to not only the performance of reliable hepatectomy but also to surgical education.

Novel 3-dimensional virtual hepatectomy simulation combined with real-time deformation

AIM: To develop a novel 3-dimensional (3D) virtual hepatectomy simulation software, Liversim, to visualize the real-time deformation of the liver.

METHODS: We developed a novel real-time virtual hepatectomy simulation software program called Liversim. The software provides 4 basic functions: viewing 3D models from arbitrary directions, changing the colors and opacities of the models, deforming the models based on user interaction, and incising the liver parenchyma and intrahepatic vessels based on user operations. From April 2010 through 2013, 99 patients underwent virtual hepatectomies that used the conventional software program SYNAPSE VINCENT preoperatively. Between April 2012 and October 2013, 11 patients received virtual hepatectomies using the novel software program Liversim; these hepatectomies were performed both preoperatively and at the same that the actual hepatectomy was performed in an operating room. The perioperative outcomes were analyzed between the patients for whom SYNAPSE VINCENT was used and those for whom Liversim was used. Furthermore, medical students and surgical residents were asked to complete questionnaires regarding the new software.

RESULTS: There were no obvious discrepancies (i.e., the emergence of branches in the portal vein or hepatic vein or the depth and direction of the resection line) between our simulation and the actual surgery during the resection process. The median operating time was 304 min (range, 110 to 846) in the VINCENT group and 397 min (range, 232 to 497) in the Liversim group (P = 0.30). The median amount of intraoperative bleeding was 510 mL (range, 18 to 5120) in the VINCENT group and 470 mL (range, 130 to 1600) in the Liversim group (P = 0.44). The median postoperative stay was 12 d (range, 6 to 100) in the VINCENT group and 13 d (range, 9 to 21) in the Liversim group (P = 0.36). There were no significant differences in the preoperative outcomes between the two groups. Liversim was not found to be clinically inferior to SYNAPSE VINCENT. Both students and surgical residents reported that the Liversim image was almost the same as the actual hepatectomy.

CONCLUSION: Virtual hepatectomy with real-time deformation of the liver using Liversim is useful for the safe performance of hepatectomies and for surgical education.

A study of the right intersectional plane (right portal scissura) of the liver based on virtual left hepatic trisectionectomy

BACKGROUND

Left hepatic trisectionectomy is a challenging procedure. For an anatomically correct resection, it is necessary to have understanding of the right intersectional plane; however, little is known on this issue. The purpose of this study was to investigate the 3D anatomy of the right intersectional plane and to enable safe and precise left trisectionectomy.

METHODS

A virtual left trisectionectomy was performed using 3D-processing software, in patients who underwent computed tomography. The reconstructed images were reviewed, and attention was paid to the extent of the right hepatic vein (RHV) exposure on the transected plane and the type of the inferior right hepatic vein (IRHV).

RESULTS

Of the 200 study patients, 109 (54.5 %) patients showed complete exposure of the RHV on the transected plane, whereas the remaining 91 exhibited partial exposure. In the 109 patients with complete exposure, 58 (53.2 %) patients had no IRHV and the remaining 51 had a small IRHV. None of the patients had a large IRHV. In contrast, of the 91 patients with partial exposure, only 10 (11.0 %) patients had no IRHV, 35 (38.5 %) had a small IRHV, and 46 (50.5 %) patients had a large IRHV. The incidence of IRHV types was significantly different between the two groups (P < 0.001).

CONCLUSIONS

The RHV does not always run along the right intersectional plane, i.e., the vein is not always fully exposed on the transected plane even after anatomically correct left trisectionectomy. The extent of the RHV exposure is closely related to the type of the IRHV.

Liver planning software accurately predicts postoperative liver volume and measures early regeneration

BACKGROUND

Postoperative or remnant liver volume (RLV) after hepatic resection is a critical predictor of perioperative outcomes. This study investigates whether the accuracy of liver surgical planning software for predicting postoperative RLV and assessing early regeneration.

STUDY DESIGN

Patients eligible for hepatic resection were approached for participation in the study from June 2008 to 2010. All patients underwent cross-sectional imaging (CT or MRI) before and early after resection. Planned remnant liver volume (pRLV) (based on the planned resection on the preoperative scan) and postoperative actual remnant liver volume (aRLV) (determined from early postoperative scan) were measured using Scout Liver software (Pathfinder Therapeutics Inc.). Differences between pRLV and aRLV were analyzed, controlling for timing of postoperative imaging. Measured total liver volume (TLV) was compared with standard equations for calculating volume.

RESULTS

Sixty-six patients were enrolled in the study from June 2008 to June 2010 at 3 treatment centers. Correlation was found between pRLV and aRLV (r = 0.941; p < 0.001), which improved when timing of postoperative imaging was considered (r = 0.953; p < 0.001). Relative volume deviation from pRLV to aRLV stratified cases according to timing of postoperative imaging showed evidence of measurable regeneration beginning 5 days after surgery, with stabilization at 8 days (p < 0.01). For patients at the upper and lower extremes of liver volumes, TLV was poorly estimated using standard equations (up to 50% in some cases).

CONCLUSIONS

Preoperative virtual planning of future liver remnant accurately predicts postoperative volume after hepatic resection. Early postoperative liver regeneration is measureable on imaging beginning at 5 days after surgery. Measuring TLV directly from CT scans rather than calculating based on equations accounts for extremes in TLV.