Chinese expert consensus on laparoscopic hepatic segmentectomy and subsegmentectomy navigated by augmented-and mixed-reality technology combined with indocyanine green fluorescence imaging

Hepatic Surgery Group,Surgery Branch of Chinese Medical Association,Digital Medical Branch of Chinese Medical Association, Digital Intelligent Surgery Committee of Chinese Research Hospital Association, Liver Cancer Committee of Chinese Medical Doctor Association

Abstract Augmented-and mixed-reality technologies have pioneered the realization of real-time fusion and interactive projection for laparoscopic surgeries.Indocyanine green fluorescence imaging technology has enabled anatomical,functional,and radical hepatectomy through tumor identification and localization of target hepatic segments,driving a transformative shift in the management of hepatic surgical diseases,moving away from traditional,empirical diagnostic and treatment approaches toward digital,intelligent ones.The Hepatic Surgery Group of the Surgery Branch of the Chinese Medical Association,Digital Medicine Branch of the Chinese Medical Association,Digital Intelligent Surgery Committee of the Chinese Society of Research Hospitals,and Liver Cancer Committee of the Chinese Medical Doctor Association organized the relevant experts in China to formulate this consensus.This consensus provides a comprehensive outline of the principles,advantages,processes,and key considerations associated with the application of augmented reality and mixed-reality technology combined with indocyanine green fluorescence imaging technology for hepatic segmental and subsegmental resection. The purpose is to streamline and standardize the application of these technologies.

Key words: Augmented reality and mixed reality; Hepatectomy; Hepatic segmental resection; Indocyanine green; Liver neoplasms;Navigation

1. Introduction

Laparoscopic liver segmentectomy and subsegmentectomy represent an extension of anatomical liver resection,wherein the concept involves the combination of Couinaud's liver segments and subsegments as independent units for “puzzle-like” composite resection.Each liver segment and subsegment possess distinct hepatic arteries,portal veins,bile duct branches,and independent hepatic veins,rendering them autonomous functional units that can be separately or collectively resected.[1]The advantages of this approach are as follows:(1)hepatocellular carcinoma exhibits a biological propensity for dissemination along the portal vein system, forming portal venous microthrombi and corresponding satellite lesions by invading neighboring portal vein branches.From an oncological perspective,anatomical liver resection precisely removes anatomically independent subsegments, segments, or combined segments, allowing complete resection of tumor lesions and thorough eradication of potential micrometastases within the involved liver segments and vessels.[2-5](2)Minimal vascular structures,such as the portal vein,hepatic artery,and bile duct, traverse independent liver segments and subsegments,resulting in relatively avascular planes. Consequently, managing fewer ducts and collateral vessels during parenchymal transection reduces the occurrence of intraoperative bleeding,bile leakage,anddamage to vascular structures.(3)Resection of the liver tissue within the tumor-bearing portal vein territory does not affect the blood supply and reflow of the remaining liver tissue,avoiding ischemic remnants owing to the lack of inflow and outflow channels,which aligns with anatomical and physiological considerations. (4) Preoperative planning of the liver segment and subsegment surgery based on intrahepatic anatomical planes enables the simultaneous achievement of satisfactory margins and resection of the tumor-bearing portal vein territory, thereby maximizing the preservation of functional liver parenchyma and addressing both the completeness and safety aspects of the procedure.

However,the overall development and widespread adoption of laparoscopic liver segmentectomy and subsegmentectomy remain challenging. The fundamental reason for this is that visualizing the boundaries between liver segments and subsegments is more challenging than hemihepatectomy.Relying solely on 2-dimensional imaging modalities,such as ultrasound and computed tomography,during surgery makes it difficult to accurately localize and control the target hepatic pedicle and delineate the extent of the tumor-bearing portal vein territory.

The advent of virtual humans ushered in an era of digital medicine,enabling the digitization of human anatomy.[6]The emergence of 3-dimensional(3D)visualization and 3D printing has revolutionized the 2-dimensional diagnostic methods for hepatic,biliary,pancreatic, and splenic diseases, facilitating preoperative visualization of liver tumors and vascular morphology.[7]Indocyanine green fluorescence imaging not only visualizes the borders of tiny tumors intraoperatively but also enables the visualization of liver segments and subsegments.[7]The development of augmented- and mixed-reality navigation surgical systems has enabled real-time fusion and interaction of novel multimodal images in liver surgery,making the visualization of anatomical, radical, and functional liver resections feasible.[7,8]To standardize the application of these technologies in liver segmentectomy and subsegmentectomy procedures and facilitate their widespread adoption, the Hepatobiliary Surgery Group of the Chinese Society of Surgery, the Digital Medicine Branch of the Chinese Medical Association,the Digital Intelligent Surgery Professional Committee of the China Research Hospital Association,and the Hepatocellular Carcinoma Committee of the Chinese Physician Association jointly organized experts in the relevant fields in China to develop this consensus.

2. Application of liver segmentectomy and subsegmentectomy

Liver segmentectomy and subsegmentectomy emphasize tumor-centered resections,focusing on the removal of the tumor-bearing portal vein territory of the liver segment while adhering to the principle of preserving the functional liver parenchyma.[9]In clinical practice,these procedures are applied in the following scenarios:

(1)For tumors located in the central hepatic region (liver segments 4 + 5 + 8), an anatomical central hepatectomy (segments 4+5+8)can be performed while preserving segments 2+3+6+7.

(2)Hjortsjo[10]introduced a novel segmentation method by further dividing liver segments 5+8 into ventral and dorsal segments based on the portal vein territory, following Couinaud traditional liver segmentation. This innovative segmentation approach allows optimization of anatomical central hepatectomy(segments 4+5+8)into reduced central hepatectomy (segments 4 + 5 + 8v). In cases of right hepatic lobectomy for right hepatic tumors, the approach can be tailored based on tumor size and involvement of the portal vein territory to include the right anterior(segments 5+8),posterior(segments 6+7),upper(segments 7+8),lower(segments 5+6),or posterior+posterior section(segments 5+6+7+8d)resections or minimally invasive right hepatic resections.[11]

(1)In patients with left hepatic tumors and relatively small left hepatic volumes,concurrent liver cirrhosis and liver atrophy-hypertrophy complex can occur.This imbalance in the left and right hepatic volumes,with the volume of the left lobe occasionally surpassing that of the right lobe,necessitates an optimized surgical approach based on the tumor's involvement in the portal vein territory and hepatic veins.This may involve segment 2 or 3,4,or 3+4b resections,among other anatomical liver segments and subsegment resections,to preserve more liver parenchyma.[12]

(2)For tumors located within a single liver segment,anatomical single-liver segment or subsegment resection can be performed to preserve the additional liver parenchyma while ensuring negative margins.

Recommendation 1: For patients requiring combined-segment,single-segment,or subsegment resections,the surgical approach should be optimized by analyzing preoperative 3D visualization models.This personalized surgical plan ensures negative surgical margins while preserving more functional liver parenchyma.

3. Preoperative 3D visualization assessment in patients with liver cancer

The import of submillimeter-thick computed tomography data into abdominal medical image 3D visualization systems facilitates segmentation,automatic registration, and 3D reconstruction.[13]Subsequent evaluations include the following: (1) observing the adjacent relationships of abdominal organs, vessels, and tumors, from different angles to assess the resectability of liver tumors; (2) performing portal-based drainage analysis[14]to clarify the number and origin of portal venous branches within the tumor-bearing liver segment,acquiring the morphology and range of the target liver segment, and planning the staining scheme[15]; (3) calculating the remaining liver volume,determining the surgical approach,and simulating liver resection; and (4) using augmented- and mixed-reality navigation fusion registration during laparoscopic liver segmentectomy and subsegmentectomy.

Recommendation 2: For patients requiring combined-segment,single-segment, or subsegment resections,a thorough analysis and evaluation of 3D visualization models, especially the portal vein branching pattern of segments 5 and 8,should be conducted preoperatively.This serves as the basis for intraoperative navigation using augmented-and mixed-reality technologies.

4. Application of indocyanine green fluorescence imaging in laparoscopic liver segmentectomy and subsegmentectomy

Indocyanine green fluorescence imaging is an application of augmented-and mixed-reality navigation technologies.The timing,route,and dosage of indocyanine green injection can be determined according to its intended use.In addition,the indocyanine green retention rate at 15 minutes can be used to preoperatively assess the timing of indocyanine green injection. Intraoperatively, fluorescence detection devices are used to scan the liver.Based on the fluorescence signal characteristics of liver tumors,tumor differentiation can be initially assessed.This technique is also used to define tumor boundaries,determine preresection liver segment boundaries,detect small cancer lesions,perform bile duct fluorescence imaging for precise localization of extrahepatic bile ducts,and detect residual tumor lesions and bile leakage on the liver resection surface postresection.Specific operational details are reported in previous studies.[16]

Recommendation 3: For patients requiring combined segment,segment, or subsegment resection, the advantages of indocyanine green fluorescence imaging should be fully used during surgery.This includes the initial assessment of tumor properties,delineation of tumor boundaries,determination of preresection liver segment boundaries,detection of small cancerous lesions,localization of extrahepatic bile ducts,and detection of postoperative bile leakage.

5. Methods for determining liver resection boundaries

Accurate determination of the liver transection plane is a key challenge in liver segmentectomy and subsegmentectomy.Traditional methods for defining liver resection planes include(1)surface anatomical landmarks of the liver (Couinaud segmentation), (2) identification of the ischemic demarcation line by controlling the hepatic pedicle of the target liver segment, and (3) portal vein puncture staining of the target liver segment.[17]With a deeper understanding of the intrahepatic anatomy, it has become evident that the boundaries between liver segments are complex curved surfaces rather than simple planes. In addition, owing to complex variations in hepatic vasculature, a single Couinaud liver segment may have multiple supplying portal vein branches or multiple draining hepatic vein branches. Relying solely on surface anatomical landmarks to perform liver segmentectomy may not accurately represent the actual extent of the target liver segment,potentially causing ischemia or congestion in the remaining liver tissue,which may not meet the requirements of anatomical liver resection.Therefore,dividing the liver segments based on the ischemic range after ligating the corresponding hepatic pedicle or puncture staining range is more accurate than relying on the surface anatomical landmarks and hepatic vein divisions.

The use of indocyanine green fluorescence imaging has made precise liver segmentectomy feasible, primarily through positive and negative staining methods.(1)For single segment or subsegment resections,positive staining is generally used.Surgeons identify the hepatic pedicle of the target liver segment with the assistance of ultrasound and gradually inject indocyanine green from the liver surface toward the tumor-bearing portal vein branches.By adjusting the injection volume and changing the color intensity and range within the liver,the boundaries of the liver segment are marked on the liver surface,facilitating the identification of the transection plane for accurate tumor removal.(2)For combined liver segment resection,the vascular supply of the target liver segment is dissected in advance and temporarily occluded to observe hepatic ischemia,and negative staining is performed by injecting indocyanine green from peripheral veins to further clarify the extent of liver resection.(3)After successful positive staining,owing to dye leakage and blood reflux,staining of the remaining liver segments commonly occurs within a few minutes.Rapid labeling should be completed to prevent unclear boundaries caused by prolonged staining.Simultaneously,the indocyanine green used during surgery should be diluted to 0.025 mg/mL, with 3 to 5 mL of the indocyanine green dilution injected per liver segment.This minimizes the staining of the remaining liver tissue.(4)Positive staining requires surgeons to possess proficient ultrasound-guided puncture techniques that are not available to many domestic physicians,limiting their use.(5)In combined liver segmentectomy,numerous portal venous branches supply the targeted resected liver segment.Although intraoperative ultrasound can assist in locating these branches,positive staining remains challenging for all branches and is time consuming. Failure to puncture presents difficulties. During the surgical procedure,indocyanine green fluorescence imaging,combined with white light and fluorescent laparoscopic imaging,allows real-time visualization of the boundary between fluorescent-positive and fluorescent-negative areas, facilitating navigated liver resection.Experienced operators can use positive staining methods.

Recommendation 4: For the localization of liver segment resection boundaries during laparoscopic liver segmentectomy and subsegmentectomy, using augmented-reality navigation combined with intraoperative ultrasound is recommended to locate the target vessels and perform ligation, followed by the use of indocyanine green fluorescence imaging to display the liver resection boundaries based on individualized circumstances.

6. Augmented-and mixed-reality navigation technology

Augmented- and mixed-reality navigation systems, principles,equipment for laparoscopic liver resection, operative procedures,and advantages of augmented-and mixed-reality navigation in laparoscopic liver resection are detailed in the literature.[18]

7. Laparoscopic liver resection with augmented-and mixed-reality navigation for different liver segments and subsegments

7.1. Laparoscopic resection of a single liver segment with augmented-and mixed-reality navigation

7.1.1. Laparoscopic resection of liver segment 1 with augmented and mixed-reality navigation

The procedure begins with dissection of the falciform ligament between the left lateral segment of the caudate lobe and the left side of the inferior vena cava, exposing the confluence of the left hepatic vein,middle hepatic vein,and inferior vena cava[19](Video 1).Intraoperative ultrasound is used to identify the course of the middle and left hepatic veins.Augmented-reality navigation confirms the relationship between the tumor and inferior vena cava,as well as the portal venous branches supplying the caudate lobe and hepatic vein branches draining it.The communication branches between the tumor and inferior vena cava are meticulously occluded with titanium clips or ligated with sutures and then transected.If the tumor invades the wall of the inferior vena cava,the affected section of the inferior vena cava wall is resected along with the tumor and sutured.Gentle traction of the caudate lobe toward the anterior and lateral directions exposes the hepatic pedicle entering the caudate lobe,which is then carefully dissected and ligated.The Spigelian fissure defines the posterior boundary,whereas the anterior boundary consists of the origins of the left,middle,and right hepatic veins.The inferior boundary is the hepatic pedicle,and the medial boundary is defined by the Arantius duct. The boundary between the caudate lobe and posterior segment of the liver can be revealed using reverse staining techniques. Depending on the tumor location, the left or right approach or a combination of both is used to transect the hepatic vein branches supplying the caudate lobe, including the tumor-involved caudate lobe tissue.[20]

7.1.2. Laparoscopic resection of liver segment 2 with augmented-and mixed-reality navigation

Left lateral lobe resection is generally considered more in line with the principles and standards of curative tumor treatment, whereas isolated resection of liver segment 2 is time consuming (Video 2).Therefore, laparoscopic anatomical resection of liver segment 2 is generally applicable in patients with severe cirrhosis, insufficient liver reserve function, segment 2 liver cancer, benign lesions, and certain cases of metastatic liver cancer.[21]

7.1.3. Laparoscopic resection of liver segment 3 with augmented-and mixed-reality navigation

A thorough dissection is performed from the left triangular and coronary ligaments to the root of the left hepatic vein(Video 3).Liver dissection begins at the left of the coronary ligament and proceeds in a caudal-to-cranial direction, reaching the sagittal portion of the portal vein.Augmented-reality navigation guides further dissection along the portal vein,with the first branch to the left being the portal vein branch of liver segment 3.Occasionally,there are 2 branches.After occlusion and transection, the extent of liver segment 3 can be determined based on the ischemic line.Following identification of the root of the left hepatic vein,the liver parenchyma is dissected from the center to the periphery along its course,leading to the complete removal of liver segment 3.

7.1.4. Laparoscopic resection of liver segment 4 with augmented-and mixed-reality navigation

The round ligament of the liver is lifted,and the liver parenchyma is incised along the right side of the round ligament to isolate the branches supplying liver segment 4 from the portal vein (Video 4).Numerous branches in this region often require dissection along the right side of the round ligament under real-time augmented-reality navigation until the primary branches of the right hepatic vein are reached.This helps in identifying and occluding the branches supplying liver segments 4a and 4b. After occlusion and transection,the ischemic line of liver segment 4 becomes evident,or fluorescence boundaries can be obtained by injecting indocyanine green from the peripheral veins. This liver segment 4 is then completely resected along the boundary. During this process, the roots of the left and middle hepatic veins must be carefully protected.

7.1.5. Laparoscopic resection of liver segment 5 with augmented-and mixed-reality navigation

Liver segment 5 lacks clear anatomical landmarks on the surface.[22]Attempting to transect all the portal venous branches supplying this segment using the right anterior hepatic pedicle approach is challenging.Therefore,intraoperative ultrasound is commonly used to locate the middle hepatic vein (border between liver segments 4 and 5)and the right hepatic vein(border between liver segments 5 and 6).Dissection of liver segment 5 begins by transecting the liver parenchyma along the right side of the middle hepatic vein under real-time augmented-reality navigation, progressively ligating and transecting the tertiary branches of the portal veins supplying liver segment 5.This allows for the determination of the ischemic range of liver segment 5.Indocyanine green can be injected into the peripheral veins for negative staining to delineate the fluorescent boundaries of liver segment 5.Subsequently,the liver parenchyma is transected along the fluorescence boundaries between liver segments 5 and 6 and between liver segments 5 and 8,leading to complete resection of liver segment 5.In a few patients,significant venous branches may drain liver segment 6. Accidental transection of these branches can lead to congestion of liver segment 6.Therefore,precise preoperative planning using 3D models of the venous drainage area of the middle hepatic vein combined with real-time augmented-reality navigation aids in accurately locating and separating these branches,thereby preventing postoperative hepatic parenchymal congestion.

7.1.6. Laparoscopic resection of liver segment 6 with augmented-and mixed-reality navigation

The portal venous branches supplying liver segment 6 are commonly composed of 1 to 2 tertiary branches(Video 5).This liver segment is located closer to the edge of the liver and is easier to isolate and occlude.Preoperative analysis of 3D models of individual vascular anatomy is used to determine the course and branching of the portal venous branches supplying liver segment 6.The surgeon dissects the right posterior hepatic pedicle along the Rouviere sulcus and, guided by augmented-reality navigation, identifies and transects the tertiary branch of the portal vein supplying liver segment 6.The ischemic boundary of liver segment 6 is determined,and fluorescence boundaries can be obtained through the peripheral vein injection of indocyanine green. Liver segment 6 is then completely resected.

7.1.7. Laparoscopic resection of liver segment 7 with augmented-and mixed-reality navigation

Laparoscopic anatomical resection of liver segment 7 is technically demanding. The anatomical location of liver segment 7 is deep,making its exposure and manipulation challenging. The root of the hepatic pedicle is situated deep within the liver and exhibits significant variability,which often leads to disorientation during identification. The right hepatic vein is notably robust,with numerous branches and a low position, rendering hemostasis a challenging endeavor. To facilitate access to the right subcostal region, the patients are positioned in various degrees of left lateral decubitus, tilting the liver toward the left side and creating a larger working space in the right subcostal region. Typically,the right liver is fully mobilized to facilitate subsequent maneuvers.The liver is then elevated toward the abdominal side while following the Rouviere sulcus as a guide, aided by augmented-reality technology.Segment 7 of the liver is situated on the dorsal aspect.Dissecting the adjacent liver parenchyma,particularly the part adjacent to the vena cava,is advantageous for revealing the hepatic pedicle of segment 7. Once the hepatic pedicle of segment 7 is encircled and occluded,an ischemic demarcation line is established.This boundary is further defined by fluorescence imaging after administration of an indocyanine green dye.The liver parenchyma is then transected along the fluorescence boundary, guided by the main trunk of the right hepatic vein, until it reaches the root of the right hepatic vein.

7.1.8. Laparoscopic resection of liver segment 8 with augmented-and mixed-reality navigation

Liver segment 8 resection can be approached using 3 distinct methods(Video 6).The first method involves positive staining and ultrasound-guided puncturing of the portal venous branches supplying segment 8.After injection of indocyanine green dye,the fluorescence boundary of segment 8 is visualized and subsequently resected using the positive staining technique.The second approach involves dissection and ligation of the portal vein branches of segment 8 using the first hepatic hilum approach.However,the portal venous branches in segment 8 typically reside at a higher position,and during the process of separation,some branches from segment 5 may be sacrificed,potentially leading to ischemic necrosis in segment 5 and postoperative bile leakage. The third and most commonly used method involves an approach through the hepatic parenchyma,detailed as follows.

The procedure begins with dissection of the round and falciform ligaments up to the second hepatic hilum,exposing the roots of the middle and right hepatic veins and inferior vena cava recess.When necessary,the right lobe of the liver is appropriately mobilized,particularly in cases involving posterior section resection.Augmented-reality navigation,in conjunction with intraoperative ultrasound,provides a more intuitive and rapid means of locating the tumor boundaries on the liver surface,delineating the course of the middle hepatic vein,and identifying the position of the portal pedicle of segment 8,thereby facilitating precise marking.

The liver parenchyma is first transected along the left plane of segment 8, where the main trunk of the middle hepatic vein projects onto a diaphragmatic surface. This transection exposes the main trunk of the middle hepatic vein and extends it to its confluence with the inferior vena cava. During this course, the portal pedicle branches supplying segment 8,which are also responsible for the intersegmental connections between segments 5 and 8(ie,the plane of segment 8),are occluded and ligated.In addition,indocyanine green (0.5 mg) is administered intravenously to mark the fluorescence boundary.

The root of the right hepatic vein is exposed upon reaching the inferior vena cava recess. This region serves as a navigation landmark,with the main trunk of the right hepatic vein and fluorescent markings guiding the surgeon. Proper attention is provided to dealing with the portal pedicle branches originating from the right hepatic vein.Transection of the liver parenchyma is then completed to achieve the desired resection of the liver parenchyma.The main challenges in the anatomical resection of liver segment 8 lie in exposing the hepatic veins and occluding the portal pedicle of segment 8.[23]In this context, the application of augmented-reality technology for intraoperative navigation is crucial for identifying the main trunk of the middle hepatic vein and differentiating the portal pedicle branches of segment 8,thereby avoiding inadvertent injury to the segmental inflow veins and preventing postoperative congestion in segment 5.Surgeons can effectively use real-time augmented-reality navigation in conjunction with the course of the hepatic vein branches between segments 5 and 8 to locate and occlude the portal pedicle of segment 8,ensuring clear delineation of the ischemic boundary on the surface of segment 8. The portal pedicle of segment 8 can present as either a main trunk type or a branch type,with its branches including the ventral,dorsal,lateral,and medial branches,which can be individually ligated or collectively occluded following direct occlusion of the main trunk.

Recommendation 5:For single-segment resections involving segments 3,4,5,and 6,direct portal pedicle ligation using a hepatic hilum approach without augmented-or mixed-reality navigation is a viable approach. This can be combined with indocyanine green fluorescence imaging to delineate the boundaries of resected liver segments.In cases of hepatic segments with elevated portal pedicle positions and intricate segmental branches, such as those seen in single-segment resections of segments 2, 7, and 8, augmented- or mixed-reality navigation should be used.This approach,combined with intraoperative ultrasonography and hepatic parenchymal entry,facilitates precise localization and control of the portal pedicle of the target segment. This procedure can be effectively guided by using indocyanine green fluorescence imaging to achieve anatomical resection of the liver segment.

7.2. Augmented-and mixed-reality-assisted indocyanine green fluorescence imaging navigation for complex hepatectomies involving multiple liver segments

In cases involving the resection of large tumors spanning 2 or more liver segments,the surgical approach of combined hepatectomy,which aims to preserve the maximal volume of functional liver parenchyma while ensuring negative surgical margins and excising the portal vein inflow region of the tumor,significantly increases the surgical complexity. Common forms of combined hepatectomies include but are not limited to resections involving liver segments 4+5+8,5+8,6+7,5+6,7+8,and 2+3.Combined hepatectomy involves individualized segmental resection based on portal venous anatomy at the level of the tertiary,quaternary,or subsegmental branches,with the primary goal of preserving functional liver volume while ensuring tumor clearance.Proficiency in meticulous anatomical dissection is imperative for the successful implementation of complex combined hepatectomies,with the foremost challenge being the preservation of intact inflow and outflow of the remaining liver segments.[24,25]

Surgeons must engage in precise preoperative surgical planning using visualization techniques.Intraoperatively,real-time image fusion navigation is used to visualize the spatial relationships among the hepatic arteries and portal and hepatic veins within the liver parenchyma.This aids in selecting the optimal approach,such as the first porta hepatis or the liver parenchyma route,and subsequently isolating and ligating the target portal vein tributaries and hepatic arterial branches.Fluorescence counterstaining techniques are used to demarcate the boundaries of the combined hepatectomy lines,often necessitating multiple temporary occlusions of the target vessels.In addition,real-time fusion and interactive navigation are used to locate the main hepatic vein trunk and its tributaries during liver resection, ensuring the preservation of venous outflow and preventing postoperative liver congestion.

Recommendation 6:For complex combined hepatectomy procedures,we recommend the use of augmented-and mixed-reality navigation. Based on individualized 3D surgical planning, this approach involves separation and ligation of the hepatic pedicles and hepatic venous outflow branches with guidance from indocyanine green fluorescence imaging to delineate the resection boundaries.

7.3. Augmented-and mixed-reality-assisted ultrasonography navigation for subsegmental liver resection

Subsegmental liver resection is performed with precision planning and implementation,organized based on the subsegmental units of the portal vein,such as the right posterior lobe combined with segments 5d + 8d, the right posterior lobe combined with individual segment 8d, or the right posterior lobe combined with individual segment 5d,to achieve partial hepatectomy of the right liver lobe.[26]The challenging aspect of its implementation lies in the necessity of preoperative analysis of 3D visual models to accurately discern the course and variations of subsegmental branch vessels.Considering the significant vascular variability within the liver,subsegmental resection boundaries may differ.This necessitates an analysis of tumor distribution within liver segments and subsegments in relation to vascular spatial relationships. The residual liver volumes need to be assessed,adhering to the principles of radical resection and maximal preservation of liver volume,to define personalized subsegmental resection boundaries and surgical interfaces.

Intraoperatively,the real-time fusion of augmented-reality technology is used in conjunction with intraoperative ultrasonography to precisely localize the portal vein subsegmental branch vessels.The subsegmental resection line is determined by projecting a line connecting the root of the hepatic vein and the origin of the portal vein subsegmental branch onto the diaphragmatic surface of the liver,which is visualized through indocyanine green negative staining.Throughout the resection,meticulous attention is paid to the integrity of the subsegmental inflow veins.A comprehensive overview of the surgical techniques can be found in reference.[18]

Recommendation 7: For patients undergoing laparoscopic subsegmentectomy,integrating 3D reconstruction models,indocyanine green fluorescence imaging, and laparoscopic scenes in conjunction with intraoperative ultrasound localization of the portal venous subsegmental branches is suggested to facilitate the visualization-guided subsegmentectomy procedure.

In conclusion, the application of augmented- and mixed-reality navigation in laparoscopic hepatic segment and subsegment resection provides several distinct advantages for surgeons.This technology enables surgeons to precisely determine the location of hepatic tumors, swiftly locate target vessels, and achieve intraoperative visualization of the hepatic segment boundaries. Consequently,it promotes the precision, standardization, and optimization of hepatic segment and subsegment resection procedures. Moreover,it enhances the confidence of surgeons during intricate surgical interventions.

Financial support and sponsorship

National Key Research and Development Program(2016YFC0106500800);National Major Scientific Instruments and Equipments Development Project of National Natural Science Foundation of China (81627805);National Natural Science Foundation of China-Guangdong Joint Fund Key Program(U1401254);National Natural Science Foundation of China Mathematics Tianyuan Foundation (12026602);Guangdong Provincial Natural Science Foundation Team Project(6200171); Guangdong Provincial Health Appropriate Technology Promotion Project(20230319214525105,20230322152307666).

Conflict of interest disclosure

X.-P.Chen is an editorial board member of Oncology and Translational Medicine. This article is subject to the journal's standard procedures, with peer review handled independently of the relevant editorial board member and his/her research groups.

Committee of authors and writing contributors

Chairpersons: Xiaoping Chen (Tongji Hospital, Tongji Medical College,Huazhong University of Science and Technology)

Chihua Fang(Zhujiang Hospital,Southern Medical University)

Members(in alphabetical order by last name):

Ping Bie (The Third Affiliated Hospital of Chongqing Medical University)

Jianqiang Cai (Cancer Hospital, Chinese Academy of Medical Sciences)

Xiujun Cai(Sir Run Shaw Hospital,Zhejiang University School of Medicine)

Minshan Chen(Sun Yat-sen University Cancer Center)

Xiaoping Chen(Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology)

Yajin Chen(The First Affiliated Hospital of Sun Yat-sen University)Lin Chen(Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology)

Shuqun Cheng (Eastern Hepatobiliary Surgery Hospital, Naval Medical University)

Yunfu Cui (The Second Affiliated Hospital of Harbin Medical University)

Chaoliu Dai(Shengjing Hospital of China Medical University)

Haining Fan(Affiliated Hospital of Qinghai University)

Chihua Fang(Zhujiang Hospital,Southern Medical University)

Lianhai Li(Dongguan First People's Hospital,Guangdong Medical University)

Peng Gong(Shenzhen University General Hospital)

Wei Guo(Beijing Friendship Hospital,Capital Medical University)Songqing He (The First Affiliated Hospital of Guangxi Medical University)

Yu He(Southwest Hospital,Army Medical University)

Deyu Li(Henan Provincial People's Hospital)

Qiang Li(Cancer Hospital,Tianjin Medical University)

Xiaowu Li(Shenzhen University General Hospital)

Xun Li(The First Hospital of Lanzhou University)

Yumin Li(The Second Hospital of Lanzhou University)

Zongfang Li (The Second Affiliated Hospital of Xi'an Jiaotong University)

Jianliang Liang (The First Affiliated Hospital of Sun Yat-sen University)

Xiao Liang(Sir Run Shaw Hospital,Zhejiang University School of Medicine)

Chang Liu (The Second Affiliated Hospital of Xi'an Jiaotong University)

Chao Liu(Sun Yat-sen Memorial Hospital,Sun Yat-sen University)Jingfeng Liu(Fujian Provincial Cancer Hospital)

Lianxin Liu (The First Affiliated Hospital of University of Science and Technology of China)

Qingguang Liu (The First Affiliated Hospital of Xi'an Jiaotong University)

Rong Liu(The First Medical Center,Chinese PLA General Hospital)Yingbin Liu(Renji Hospital,Shanghai Jiao Tong University School of Medicine)

Peng Lu(The First Medical Center,Chinese PLA General Hospital)Qian Lu(General Hospital of Central Theater Command)

Qian Lu(Tsinghua Chang Gung Hospital,Tsinghua University)

Shichun Lu(The First Medical Center,Chinese PLA General Hospital)Guoyue Lv(The First Hospital of Jilin University)

Yi Lv(The First Affiliated Hospital of Xi'an Jiaotong University)

Baogang Peng(The First Affiliated Hospital of Sun Yat-sen University)

Lunxiu Qin(Huashan Hospital,Fudan University)

Dong Shang(The First Affiliated Hospital of Dalian Medical University)Feng Shen(Eastern Hepatobiliary Surgery Hospital,Naval Medical University)

Jun Shi(The First Affiliated Hospital of Nanchang University)

Chengyi Sun (The Affiliated Hospital of Guizhou Medical University)

Shijie Sun(Yuhuangding Hospital of Qingdao)

Zhaohui Tang (Xinhua Hospital, Shanghai Jiao Tong University School of Medicine)

Jun Wan (Li Ka Shing Faculty of Medicine, The University of Hong Kong)

Hongguang Wang(Cancer Hospital,Chinese Academy of Medical Sciences)

Huaizhi Wang (Chongqing Hospital of the University of Chinese Academy of Sciences)

Jian Wang(The Sixth People's Hospital of Shanghai)

Jianming Wang(Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology)

Lu Wang(Cancer Hospital,Fudan University)

Xiaoying Wang(Zhongshan Hospital,Fudan University)

Hao Wen(The First Affiliated Hospital of Xinjiang Medical University)

Tianfu Wen(West China Hospital,Sichuan University)

Dequan Wu (The Second Affiliated Hospital of Harbin Medical University)

Hong Wu(West China Hospital,Sichuan University)

Yulian Wu(The Second Affiliated Hospital of Zhejiang University School of Medicine)

Nan Xiang(Zhujiang Hospital,Southern Medical University)

Xue Xing(Qingdao Municipal Hospital)

Jun Xu(The First Hospital of Shanxi Medical University)

Jian Yang(Zhujiang Hospital,Southern Medical University)

Yang Yang (The Third Affiliated Hospital of Sun Yat-sen University)

Yinmo Yang(Peking University First Hospital)

Xiaoyu Yin(The First Hospital of Hunan Province)

Yufeng Yuan(Zhongnan Hospital of Wuhan University)

Ning Zeng(Zhujiang Hospital,Southern Medical University)

Yongyi Zeng(Mengchao Hepatobiliary Hospital of Fujian Medical University)

Yong Zeng(West China Hospital,Sichuan University)

Bixiang Zhang(Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology)

Ping Zhang(The First Hospital of Jilin University)

Shuijun Zhang(The First Affiliated Hospital of Zhengzhou University)

Xuewen Zhang(The Second Hospital of Jilin University)

Yamin Zhang(Tianjin First Central Hospital)

Zhanguo Zhang(Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology)

Zhiwei Zhang(Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology)

Haoliang Zhao(Shanxi Bethune Hospital)

Shuguo Zheng(Southwest Hospital,Army Medical University)

Xuting Zhi(Qilu Hospital of Shandong University)

Lin Zhong(The First People's Hospital of Qingdao)

Jian Zhou(Zhongshan Hospital,Fudan University)

Jie Zhou(Nanfang Hospital,Southern Medical University)

Weiping Zhou (Eastern Hepatobiliary Surgery Hospital, Naval Medical University)

Peng Zhu (Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology)

Lead Authors:Chihua Fang,Jian Yang,Shuguo Zheng,Xiwon Wu(Zhujiang Hospital,Southern Medical University)

Video Editing: Haoyu Hu (Zhujiang Hospital, Southern Medical University)

This article was first published on Chinese Journal of Surgery(Chinese)2023;61(11):929-936.

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