Re-evaluation of the Couinaud classification for segmental anatomy of the right liver, with particular attention to the relevance of cranio-caudal boundaries

Right Intrahepatic Portal Vein Classification Based on Three-Dimensional Visualization With Particular Attention to the Relevance of the Right Anterior and the Right Posterior Portal Vein

BACKGROUND

The present study aimed to investigate the branching pattern of the right intrahepatic portal vein, with a particular focus on the third-order portal vein branches, and their clinical implications, utilizing three-dimensional visualization technology. This technology has the potential to assist clinicians in performing hepatectomy.

METHODS

A retrospective analysis on the branching pattern of the third-order portal branch of the right intrahepatic portal vein was conducted in 711 patients, spanning from June 2019 to June 2021, utilizing three-dimensional visualization techniques.

RESULTS

With regard to the anatomy of the right anterior portal vein, the cranio-caudal type was found in 353 patients, the ventro-dorsal type in 171 patients, the trifurcation type in 61 patients, and the quadfurcation type in 9 patients. Additionally, the right posterior portal vein was categorized into three types based on the third-order branches: the bow-shaped type was observed in 294 cases, the bifurcation type in 286 cases, and the trifurcation type in 14 cases. Consequently, the branching pattern of the right intrahepatic portal vein was classified into 12 distinct types and four special types, considering the variations in the number and course of the third-order branches originating from the right anterior and posterior portal veins.

CONCLUSIONS

The results of this study offer valuable insights into the structure of the right intrahepatic portal vein, enhancing clinicians' rational understanding and contributing to the safe execution of hepatic operative planning and decision-making.

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.

Laparoscopic anatomical SVIII resection via middle hepatic fissure approach: Caudal or cranio side

BACKGROUND

Laparoscopic hepatectomy is a proven safe and technically feasible approach for liver tumor resection, but laparoscopic anatomical SVIII resection (LASVIIIR) remains rarely reported due to poor accessibility, difficult exposure, and the deep-lying Glissonean pedicle. This study examined the safety, feasibility, and perioperative outcomes of LASVIIIR via a middle hepatic fissure approach at our institution.

AIM

To investigate the safety, feasibility, and perioperative outcomes of LASVIIIR via a middle hepatic fissure approach at our institution.

METHODS

From November 2017 to December 2022, all patients with a liver tumor who underwent LASVIIIR were enrolled. The perioperative outcomes and postoperative complications were evaluated.

RESULTS

Thirty-four patients underwent LASVIIIR via a middle hepatic fissure approach from the side or cranio side and were included. The mean operation time was 164 ± 54 minutes, and the intra-operative blood loss was 100 mL (range: 20-1000 mL). The mean operative times were, respectively, 152 ± 50 minutes and 222 ± 29 minutes (P = 0.001) for the caudal side and cranial side approaches. In addition, the median blood loss volumes were 100 mL (range: 20-300 mL) and 250 mL (range: 20-1000 mL), respectively, for the caudal and cranial sides (P = 0.064). Three patients treated using the cranial side approach experienced bile leakage, while 1 patient treated using the caudal side approach had subphrenic collection and underwent percutaneous drainage to successfully recover. There were no differences regarding postoperative hospital stays for the caudal and cranial side approaches [9 (7-26) days vs 8 (8-19) days] (P = 0.226).

CONCLUSION

LASVIIIR resection remains a challenging operation, but the middle hepatic fissure approach is a reasonable and easy-to-implement technique.

The Taping Game for the Complex G8 Glissonean Approach Is the Most Effective Technique for Laparoscopic Anatomic S8 Resection of Dandelion-Patterned Hepatic Pedicles

BACKGROUND

Laparoscopic anatomic segment 8 resection (LAR-S8) remains a technical challenge due to the special location of S8 and the complex classification of the Glissonean pedicle of S8 (G8). Particularly for situations in which multiple grade 4 hepatic pedicles branch out from the same point at 360° in a dandelion pattern from the right anterior hepatic pedicle, effective methods for accurately locating the target G8 and the intersegmental plane between S8 and the adjacent hepatic segment remain lacking.

METHODS

This report describes a LAR-S8 guided by the indocyanine green (ICG) negative-staining method using the "taping game for complex G8 Glissonean approach" in a patient with a typical dandelion-patterned G8.

RESULTS

The operative time was 150 min, with a blood loss of 50 mL and no complications. The patient was discharged 5 days postoperatively. Regular follow-up evaluation during 24 months showed no recurrence.

CONCLUSIONS

The taping game is an effective method for S8 resection, especially for patients with complex G8 patterns such as the dandelion pattern.

Indocyanine Green Fluorescence-Guided Laparoscopic Anatomical Segmentectomy of Liver Segment 6: Surgical Strategy and Technical Details

BACKGROUND

Because of the complex anatomy of the right posterior hepatic pedicle, there have been few reports on standardized laparoscopic portal territory staining-guided anatomical resection of liver segment 6 (LPTAR-S6). This study aimed to elucidate the indocyanine green (ICG) fluorescence staining methods for LPTAR-S6.

PATIENTS AND METHODS

LPTAR-S6 can be performed using positive and negative fluorescence staining approaches. We implemented these two approaches for patients with hepatocellular carcinoma. Descriptions of the surgical strategy and technical details are presented.

RESULTS

Two patients safely underwent LPTAR-S6 using a preoperative three-dimensional reconstruction plan. The intraoperative ICG fluorescence staining effect was satisfactory, and the anatomical landmarks were fully exposed.

CONCLUSIONS

A detailed preoperative three-dimensional reconstruction plan, complete intraoperative application of real-time laparoscopic ultrasound guidance, and ICG fluorescence staining can result in accurate transection of the liver parenchyma during LPTAR-S6.

Impact of three-dimensional reconstruction visualization technology on short-term and long-term outcomes after hepatectomy in patients with hepatocellular carcinoma: a propensity-score-matched and inverse probability of treatment-weighted multicenter study

BACKGROUND

Three-dimensional reconstruction visualization technology (3D-RVT) is an important tool in the preoperative assessment of patients undergoing liver resection. However, it is not clear whether this technique can improve short-term and long-term outcomes in patients with hepatocellular carcinoma (HCC) compared with two-dimensional (2D) imaging.

METHOD

A total of 3402 patients from five centers were consecutively enrolled from January 2016 to December 2020, and grouped based on the use of 3D-RVT or 2D imaging for preoperative assessment. Baseline characteristics were balanced using propensity score matching (PSM, 1:1) and stabilized inverse probability of treatment-weighting (IPTW) to reduce potential selection bias. The perioperative outcomes, long-term overall survival (OS), and recurrence-free survival (RFS) were compared between the two groups. Cox-regression analysis was used to identify the risk factors associated with RFS.

RESULTS

A total of 1681 patients underwent 3D-RVT assessment before hepatectomy (3D group), while 1721 patients used 2D assessment (2D group). The PSM cohort included 892 patient pairs. In the IPTW cohort, there were 1608.3 patients in the 3D group and 1777.9 patients in the 2D group. In both cohorts, the 3D group had shorter operation times, lower morbidity and liver failure rates, as well as shorter postoperative hospital stays. The 3D group had more margins ≥10 mm and better RFS than the 2D group. The presence of tumors with a diameter ≥5 cm, intraoperative blood transfusion and multiple tumors were identified as independent risk factors for RFS, while 3D assessment and anatomical resection were independent protective factors.

CONCLUSION

In this multicenter study, perioperative outcomes and RFS of HCC patients following 3D-RVT assessment were significantly different from those following 2D imaging assessment. Thus, 3D-RVT may be a feasible alternative assessment method before hepatectomy for these patients.

Efficacy of Augmented Reality Combined with Indocyanine Green Fluorescence Imaging Guided Laparoscopic Segmentectomy for Hepatocellular Carcinoma

BACKGROUND

The internal anatomy of the liver is extremely complex. Laparoscopic anatomical segmentectomy requires reference to the position and alignment of intrahepatic vascular. However, the surface of the liver lacks anatomical landmarks and the liver segment boundaries cannot be identified with the naked eye. Augmented reality navigation (ARN) and indocyanine green fluorescence imaging (FI) are emerging navigation tools in liver resection. This study aimed to explore the efficacy and application value of laparoscopic anatomical segmentectomy guided by ARN combined with indocyanine green FI.

STUDY DESIGN

Ninety-eight patients who were diagnosed with hepatocellular carcinoma and underwent laparoscopic anatomical segmentectomy from January 2018 to January 2022 were retrospectively analyzed. They were divided into the ARN-FI group (45 patients) and the non-ARN-FI group (53 patients) based on whether ARN combined with FI was applied during the operation. The differences in intraoperative and postoperative outcomes were compared.

RESULTS

There was no significant difference in preoperative baseline data and postoperative complication rates between the 2 groups. Compared with the non-ARN-FI group, the ARN-FI group had much lower intraoperative blood loss (100 vs 200 mL, p = 0.005) and a lower incidence of remnant liver ischemia (13.3% vs 30.2%, p = 0.046). The 1- and 3-year disease-free survival rates in the ARN-FI and non-ARN-FI groups were 91.01% vs 71.15% and 70.01% vs 52.46%, respectively; the differences between the 2 groups were statistically significant (p = 0.047).

CONCLUSIONS

The ARN-FI technology provides a more standardized approach for liver parenchyma section during laparoscopic liver resection, effectively minimizing intraoperative blood loss, reducing postoperative remnant liver ischemia, and improving oncological prognosis. This method is safe and feasible and has good clinical application prospects.

Can Hisense computer-assisted surgery system (Hisense CAS) improve anatomy teaching in pediatric liver surgery?

PURPOSE

This study aimed to investigate the effectiveness of the Hisense computer-assisted surgery system (CAS) in teaching pediatric liver surgical anatomy.

METHODS

The research subjects were residents who underwent standardized training at the Department of Pediatric Surgery at Yijishan Hospital of Wannan Medical College from May 2022 to May 2023.

RESULTS

The study recruited a total of 62 students, with 31 students assigned to the Hisense CAS group (12 males and 19 females) and the remaining 31 students serving as controls (Control group, 15 males and 16 females). There were no significant differences in baseline characteristics observed between the two groups. This study found that the average scores of the Hisense CAS teaching group in the liver surgery evaluations were higher than those of the control group. Specifically, the Hisense CAS group had an average score of 84.25 ± 5.70 points in the liver surgery knowledge test, 77.10 ± 8.12 points in the image reading test, and 70.58 ± 8.79 points in the surgical simulation test, while the traditional teaching group had average scores of 73.45 ± 6.12 points, 69.81 ± 6.05 points, and 66.42 ± 6.61 points, respectively; the differences between the two groups were statistically significant (P < 0.05). Furthermore, this study also found that the Hisense CAS teaching model resulted in significantly better teaching satisfaction on the part of the residents in terms of standardized teaching for physicians in pediatric liver surgical anatomy.

CONCLUSION

In conclusion, this study demonstrated greater satisfaction of the residents with the use of 3D reconstruction added to traditional teaching sessions and better performance during the posttraining evaluation.

Augmented Reality Navigation Plus Indocyanine Green Fluorescence Imaging Can Accurately Guide Laparoscopic Anatomical Segment 8 Resection

BACKGROUND

Laparoscopic anatomical Segment 8 (S8) resection is a highly challenging hepatectomy. Augmented reality navigation (ARN), which could be combined with indocyanine green (ICG) fluorescence imaging, has been applied in various complex liver resections and may also be applied in laparoscopic anatomical S8 resection. However, no study has explored how to apply ARN plus ICG fluorescence imaging (ARN-FI) in laparoscopic anatomical S8 resection, or explored its accuracy.

PATIENTS AND METHODS

This study is a post hoc analysis that included 31 patients undergoing laparoscopic anatomical S8 resection from the clinical NaLLRFI trial, and the resected liver volume was measured in each patient. The perioperative parameters of safety and feasibility, as well as the accuracy analysis outcomes were compared.

RESULTS

There were 16 patients in the ARN-FI group and 15 patients underwent conventional laparoscopic hepatectomy without ARN or fluorescence imaging (non-ARN-FI group). There was no significant difference in baseline characteristics between the two groups. Compared with the non-ARN-FI group, the ARN-FI group had lower intraoperative bleeding (median 125 vs. 300 mL, P = 0.003). No significant difference was observed in other postoperative short-term outcomes. Accuracy analysis indicated that the actual resected liver volume (ARLV) in the ARN-FI group was more accurate.

CONCLUSIONS

ARN-FI was associated with less intraoperative bleeding and more accurate resection volume. These techniques may address existing challenges and provide rational guidance for laparoscopic anatomical S8 resection.

Prevalence and clinical significance of the Sg6/Sg7 intersegmental veins based on re-evaluation of the Couinaud classification for the right posterior portal vein

Although Segment 6(Sg6) and Segment 7(Sg7) are two independent units, there are currently no clear anatomical boundary markers between Sg6 and Sg7. This study aimed to identify intersegmental veins (ISV) in the intersegmental plane of Sg6 and Sg7, and evaluate the prevalence of ISV, and its clinical significance in anatomical hepatectomy. We analyzed data from 180 patients undergoing abdominal computed tomography (CT) examination, and simultaneously performed 3D reconstruction models of the liver for each patient. The right posterior portal vein was analyzed and re-typed. Furthermore, the existence of ISV was defined, and prevalence and confluence patterns of ISV were analyzed. The author attempted to apply ISV to laparoscopic S6/S7 segmentectomy. We sorted data from the right posterior portal vein and divided it into six types. The ISV could be identified in 82.2% (148/180) of the patients, which were derived from the right hepatic vein (RHV) (91.9%) and right posterior inferior vein (IRHV) (8.1%). Ten ISV-guided laparoscopic Sg6/Sg7 segmentectomy were successfully carried out, seven patients underwent Sg6 segmentectomy, and three patients underwent Sg7 segmentectomy. There was no perioperative mortality. The median operative time was 223 min (range 181-260 min). The median blood loss was 200 ml (range 150-310 ml). The R0 resection rate was 100%. The ISV may be a candidate vessel to distinguish the boundary of the right posterior sector; it is expected to be a landmark in the liver parenchyma of anatomical hepatectomy.

Laparoscopic Microwave Ablation: Which Technologies Improve the Results

Liver resection is the best treatment for hepatocellular carcinoma (HCC) when resectable. Unfortunately, many patients with HCC cannot undergo liver resection. Percutaneous thermoablation represents a valid alternative for inoperable neoplasms and for small HCCs, but it is not always possible to accomplish it. In cases where the percutaneous approach is not feasible (not a visible lesion or in hazardous locations), laparoscopic thermoablation may be indicated. HCC diagnosis is commonly obtained from imaging modalities, such as CT and MRI, However, the interpretation of radiological images, which have a two-dimensional appearance, during the surgical procedure and in particular during laparoscopy, can be very difficult in many cases for the surgeon who has to treat the tumor in a three-dimensional environment. In recent years, more technologies have helped surgeons to improve the results after ablative treatments. The three-dimensional reconstruction of the radiological images has allowed the surgeon to assess the exact position of the tumor both before the surgery (virtual reality) and during the surgery with immersive techniques (augmented reality). Furthermore, indocyanine green (ICG) fluorescence imaging seems to be a valid tool to enhance the precision of laparoscopic thermoablation. Finally, the association with laparoscopic ultrasound with contrast media could improve the localization and characteristics of tumor lesions. This article describes the use of hepatic three-dimensional modeling, ICG fluorescence imaging and laparoscopic ultrasound examination, convenient for improving the preoperative surgical preparation for personalized laparoscopic approach.

Laparoscopic Anatomical Extended Right Posterior Sectionectomy Using Virtual Liver Segment Projection Navigation and Indocyanine Green Fluorescence Imaging

BACKGROUND

Extended right posterior sectionectomy is an alternative to right hepatectomy (RH) for tumors located mainly in the right posterior section (RPS) and partially in the right anterior section (RAS).1 Anatomical extended right posterior sectionectomy (AERPS) combining RPS and right anterior subsegmental resections not only achieves anatomical hepatectomy to reduce remnant liver ischemia2 but also preserves more functional liver parenchyma than RH. AERPS can be extremely challenging, especially under laparoscopy.

PATIENT AND METHODS

A 48-year-old male was admitted to our institution for a tumor in the right liver. The three-dimensional (3D) model revealed that the subsegments innervated by the P5dor and the P8lat could cover the territory of the tumor in the RAS.3 Therefore, laparoscopic AERPS was performed. First, an intrafascial approach was adopted to dissect and ligate the right posterior Glissonean pedicle. Then, we used intraoperative ultrasound and virtual liver segment projection by Laparoscopic Hepatectomy Navigation System4 to identify the intersegmental fissure between the dorsal and ventral segments of S5. Partial parenchymal transection was used to reach the common stem of G5dor and G8lat.5 Finally, using indocyanine green (ICG) negative staining fluorescence imaging, the precise transection interface was determined.

RESULTS

The operation lasted 360 min with 100 ml of intraoperative blood loss. There were no postoperative complications, and the patient was discharged after 3 days.

CONCLUSION

Laparoscopic AERPS is technically feasible and can be performed with greater precision coupled with virtual liver segment projection and ICG fluorescence imaging.

Study on the portal ramification pattern of the right anterior sector of the liver and a unique medial branch (PV8c) of the right anterior portal vein

Aim

The concept of Couinaud segmentation is widely used in clinical practice. However, there were no definite anatomical landmarks between segments V and VIII. Therefore, segmentation of the right anterior sector is still controversial. We aimed to investigate the portal segmentation of the right anterior sector using 3D image analysis, and to reveal the existence of the medial branch (PV8c), a unique, characteristic branch of the right anterior portal vein.

Methods

The ramification form and pattern of the tertiary portal branch of the right anterior portal vein were retrospectively analyzed, and the frequency of PV8c was evaluated in 261 patients between January 2016 and June 2020.

Results

The ramification pattern of tertiary portal branches of the right anterior portal vein was classified into four types: craniocaudal, 28.0% of patients; ventrodorsal, 21.8%; trifurcation, 39.5%; and quadfurcation, 5.7%, and each type was further subdivided into six patterns by focusing especially on the caudal branches. The ramification pattern in the remaining 5.0% of the livers did not belong to the above-mentioned four types. The PV8c branch was identified in 140 of 261 livers (53.6%); the mean proportion of the feeding area of PV8c in the whole liver volume was 3.4%.

Conclusion

Since the ramification pattern of tertiary portal branches of the right anterior portal vein does not necessarily show a single pattern, it is important to confirm the portal vein branching in each case during hepatectomy. This is the first study of the details of PV8c by 3D computed tomography.