Precise anatomical resection of the ventral part of Segment VIII

Comprehensive evaluation of the ramification patterns of hepatic vascular anatomy based on three-dimensional visualization technology

The liver segmentation method proposed by Couinaud is widely accepted by surgeons because of its convenience and practicality. However, this conventional eight-segment classification does not reflect realistic details of the liver and thus requires further adjustments to promote improvements in surgical strategies. This study aimed to explore the ramification patterns of the hepatic vasculature comprehensively. A total of 197 eligible patients meeting the study criteria were enrolled for three-dimensional reconstruction analysis. In the left hemiliver, the portal vein bifurcated into P2 and umbilical portion (UP) in 172 (98.3%) patients. The P4b of 103 patients (103/172, 59.9%) whose P4b branched from the right horn of the left portal vein (LPV) diverged from the main trunk of the UP. In the right paramedian sector (RPMS), the entire portal trunk directly bifurcates into P8vent and P8dor. Simple branching of P5 off the trunk of the RPMS was observed in 78 patients (78/130, 60%). The anterior fissure vein (AFV) was identified in 86 (86/148, 58.1%) patients. V8d entered the right hepatic vein (RHV) in all the patients. In 75.3% (113/150) of all the patients, V5d joined the RHV. In the right lateral sector (RLS), more than half (71/133, 53.4%) of the patients had an arch-like type. We summarize different patterns of liver vascular branches, providing a valuable reference for clinical surgery and liver transplantation. Cranio-caudal segmentation is more common than ventral-dorsal segmentation. The AFV can be regarded as a reliable anatomical landmark for subsegmentation in segment 8. In addition, the absence of AFV was associated with the P8 pattern.

Study of the Intersegmental Veins Between S5 and S8 Based on 3D Reconstruction

BACKGROUND

Anatomic resection (AR) is a surgical method for treating hepatocellular carcinoma, and identifying intersegmental planes between segments 5 (S5) and 8 (S8) remains challenging. This study aims to find reliable intersegmental veins (IVs) between them as anatomical landmarks using 3D reconstruction analysis.

METHODS

We retrospectively evaluated 57 patients who underwent multidetector-row CT scans from September 2021 to January 2023. The portal vein watershed of S5 and S8 and hepatic veins were reconstructed using 3D reconstruction analysis software. We counted and analyzed the IVs running within the intersegmental plane between S5 and S8, examined their features, and analyzed the location of the junctions between IVs and middle hepatic veins (MHVs).

RESULTS

Among the 57 patients, 43 patients (75.4%) had IVs between S5 and S8. Most patients (81.4%) had a single IV joining the MHV, while 13.9% had two IVs, one joining the MHV and the other joining the right hepatic vein (RHV). The majority of IV-MHV junctions were found in the lower part of the MHVs. The most clearly identifiable junctions between the IVs and MHVs occurred slightly below the midpoint of the horizontal planes of the second hepatic portal and the center of the gallbladder bed.

CONCLUSION

Our study identified IVs between S5 and S8 in the liver as potential anatomical landmarks during AR for hepatocellular carcinoma surgery. We found three types of IVs and provided insights on how to locate their junctions with MHVs for easier surgical navigation. However, individual anatomical variations must be considered, and preoperative 3D reconstruction and personalized surgical planning are crucial for success. More research with larger sample sizes is needed to validate our findings and establish the clinical significance of these IVs as landmarks for AR.

Laparoscopic liver resection of segment 8 via a hepatic parenchymal transection-first approach guided by the middle hepatic vein

Background

Pure laparoscopic liver resection (LLR) of segment 8 (S8) is still rarely performed due to the lack of an appropriate surgical approach. This article discusses the technical tips and operation methods for LLR of S8 via a hepatic parenchymal transection-first approach.

Methods

Clinical data of 22 patients who underwent LLR of S8 via a hepatic parenchymal transection-first approach guided by the middle hepatic vein (MHV) in the Second Affiliated Hospital, Third Military Medical University (Army Medical University) from May 2017 to February 2020 were retrospectively analyzed.

Results

The mean age was 51.1 ± 11.6 years; mean operation time, 186.6 ± 18.4 min; median blood loss, 170.0 ml (143.8–205.0 ml); and median length of hospital stay, 8.0 days (7.0–9.0 days). There was no case of open conversion. Pathologic findings revealed all cases of hepatocellular carcinoma (HCC). Pathology showed free surgical margins. Post-operative complications included liver section effusion, pleural effusion, pneumonia, intra-abdomen bleeding and bile leak. All the complications responded well to conservative treatment. No other abnormality was noted during outpatient follow-up examination. All patients survived tumor-free.

Conclusions

LLR of S8 is still quite challenging at present, and it is our goal to design a reasonable procedure with accurate efficacy and high safety. We use hepatic parenchymal transection-first approach guided by the MHV for LLR of S8. This technique overcomes the problem of high technical risk, greatly reduces the surgical difficulty and achieves technological breakthroughs, but there are still many problems worth further exploration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02289-8.

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.

Human liver territories: Think beyond the 8-segments scheme

Worldwide, compartmentalization of the human liver into portal venous territories today follows the eight-segments scheme credited to Couinaud. However, there are increasing reports of anatomical, radiological and surgical observations that contradict this concept. This paper presents a viewpoint that enhances understanding of these inconsistencies and can serve as a basis for customized liver interventions. Clin. Anat. 30:974-977, 2017. © 2017 Wiley Periodicals, Inc.

Usefulness of three-dimensional(3D) simulation software in hepatectomy for pediatric hepatoblastoma

BACKGROUND

Hepatoblastoma (HB) is the most common malignant liver tumor in childhood. Complete HB surgical resection which is technically demanding is the cornerstone of effective therapy with a good prognosis. The aim of our study is to evaluate the usefulness of 3D simulation software in assisting hepatectomy in pediatric patients with HB.

METHODS

21 children with HB who underwent hepatectomy were enrolled in this study. All patients underwent computer tomography (CT) imaging preoperatively. CT images from 11 cases (from September 2013 to August 2015) were reconstructed with Hisense CAS, and performed hetpatectomy. While 10 cases (from September 2011 to August 2013) without 3D simulation were token as the control group. The clinical outcome were analyzed and compared between the 2 groups.

RESULTS

All the HB were successfully removed for all patients and there was no positive margins in the surgical specimens, no complications, and no recurrences. For the reconstructing group, 3D simulation software successfully reconstructed the 3D images of liver and were used as a navigator in the operation room during hepatectomy. Anatomic hepatectomy were successfully completed for all patients after operation planning using the software. There was no obvious discrepancy between the virtual and the actual hepatectomy. The mean operation time was shorter (142.18 ± 21.87 min VS. the control group, 173.5 ± 54.88 min, p = 0.047) and intraoperative bleeding was less (28.73 ± 14.17 ml VS. 42.8 ± 41.12 ml, p = 0.011) in the reconstructing group. Moreover, postoperative hospital stay tended to be shorter in the reconstructing group (11.18 ± 2.78d VS. the control group 13 ± 3.46d, P = 0.257).

CONCLUSIONS

3D simulation software facilitates the investigation of the complex liver structure, contributes to the optimal operation planning, and enables an individualized anatomic hepatectomy for each pediatric patient with HB.

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.