| Background and objectivesLaparoscopic anatomical liver segment 8(S8)resection is one of the most difficult hepatic segmentectomy,and its difficulties mainly include the following two aspects:first,the P8 branch of liver S8 is complex and variation is common,and there is a lack of P8 three-dimensional visualization classification to guide clinical practice.Second,the resection of S8 has left,right,dorsal and transverse sections,and there are many surgical sections.Especially,the interface between S5 and S8 segments lacks obvious anatomical landmarks to guide,and it is difficult to accurately control the surgical section.The objectives of this study include:1.Summarize the P8 classification based on 3D visualization technology,analyze the volume of the portal vein drainage area of S8 subsegment,and evaluate the occurrence of the anterior fissure vein and the S5/S8 intersegmental vein and the role of anatomical landmarks between segments;To explore the feasibility of augmented reality(AR)navigation combined with indocyanine green(ICG)fluorescence imaging technology in accurately guiding laparoscopic anatomical liver S8 resection.Methods1.The imaging data of patients who underwent contrast-enhanced CT examination of the upper abdomen in Zhujiang Hospital of Southern Medical University from September 2020 to September 2022 were analyzed.High-quality thin-slice CT data were selected for three-dimensional reconstruction of the liver and blood vessel model using three-dimensional visualization technology.According to the direction of the third-level or fourth-level P8 branches,the P8 three-dimensional visualization classification was summarized.The volume of the portal vein drainage area of S8 subsegment,the occurrence rate of the anterior fissure vein and the S5/S8 intersegmental vein and the ratio as an anatomical landmark between segments were statistically analyzed.2.The clinical data of patients with hepatocellular carcinoma located in the S8 admitted to the First Department of Hepatobiliary Surgery,Zhujiang Hospital,Southern Medical University from October 2021 to October 2022 were collected.During the operation,the laparoscopic augmented reality surgical navigation system was used to register and fuse the preoperative three-dimensional liver model with the laparoscopic intraoperative images,and ICG fluorescence imaging technology was used to guide the anatomical liver S8 resection.The preoperative virtual liver resection volume and actual liver resection volume,perioperative indicators and surgical complications were analyzed.Results1.A total of 200 patients were included in this part of the study.There were four types of P8 3D visualization classification:type A,P8 ventral branch(P8v)+P8 dorsal branch(P8d),49 cases(24.5%);Type B,P8 ventral branch+P8 dorsal branch+P8 medial branch(P8m),41 cases(20.5%);Type C,P8 ventral branch+P8 dorsal branch+P8 lateral branch(P81),62 cases(31.0%);Type D,P8 ventral branch+P8 dorsal branch+P8 medial branch+P8 lateral branch,48 cases(24%).According to the different discharge points of the medial or lateral branches,it was subdivided into 13 subtypes.The average volume of S8 segment was 261.11±81.92 ml,accounting for 24.48%of the total liver volume.The results of the volume analysis of the portal vein drainage area of the S8 subsegment in each type were as follows:in type A,the average volumes of the ventral and dorsal segments of S8 were 105.25±37.64 ml and 137.51±48.93 ml,respectively,accounting for 10.43%and 13.72%of the total liver volume,respectively;In type B,the average volumes of the ventral,dorsal and medial segments of S8 were 114.38±45.73 ml,105.96±47.10 ml and 39.41±17.43 ml,respectively,accounting for 11.34%,10.51%and 3.87%of the total liver volume,respectively.In type C,the average volumes of the ventral,dorsal and lateral segments of S8 were 105.71±49.18 ml,109.25±49.54 ml and 49.72±22.17 ml,respectively,accounting for 9.63%,9.89%and 4.53%of the total liver volume,respectively.In type D,the average volumes of the ventral,dorsal,lateral and medial segments of S8 were 100.52±45.08 ml,94.03±37.01 ml,48.30±16.09 ml and 33.16±29.21 ml,respectively.The average ratio to total liver volume was 8.74%,8.31%,4.28%and 2.93%,respectively.The occurrence rate of anterior fissure veins was 65.50%(131/200),of which 56.49%(74/131)could be used as an anatomical marker for the boundary between the ventral and dorsal subsegment of the S8.According to their number,they could be divided into three types:In one,two and three branches,80.91%(106/131)of the anterior fissure veins drained into the middle hepatic vein,11.45%(15/131)drained into the right hepatic vein,and 3.82%(5/131)drained into both the middle hepatic vein and the right hepatic vein.3.82%(5/131)of the anterior fissure veins drained into the inferior vena cava alone.The occurrence rate of S5/S8 intersegmental veins was 82.50%(165/200),which can be divided into 3 types according to the number:In one,two and three branches,36.97%(61/165)of the S5/S8 intersegmental veins drained into middle hepatic vein alone,7.88%(13/165)of the S5/S8 intersegmental veins drained into middle hepatic vein alone,55.15%(91/165)of the S5/S8 intersegmental veins drained into middle hepatic vein and right hepatic vein at the same time.2.A total of 8 patients with hepatocellular carcinoma were included in this part of the study,including 5 males and 3 females,aged from 40 to 72 years old.Among them,4 patients underwent laparoscopic anatomical liver S8 segment resection,1 patient underwent laparoscopic anatomical liver S8 ventral segment resection,2 patients underwent laparoscopic anatomical liver S8 ventral segment combined with medial segment resection,and 1 patient underwent laparoscopic anatomical liver S8 dorsal segment resection.All operations were completed under the guidance of augmented reality navigation combined with ICG fluorescence imaging.There was no conversion to open surgery.The operation time was 200-360 minutes,the average operation time was 276 minutes,the average intraoperative blood loss was 75ml,no blood transfusion was performed during the operation.There was no death during the perioperative period,and no complications such as bleeding and biliary fistula occurred after operation.Conclusions1.According to the course of the third or fourth grade P8 branches,the 3D visualization classification of P8 branches was summarized based on the 3D visualization technology.The P8 branches could be divided into four types and 13 subtypes.The volume of the portal vein drainage area of the S8 subsegment,the distribution of the anterior fissure vein and the veins between the S5/S8 segments were statistically analyzed.P8 three-dimensional visualization classification can help surgeons to deepen the understanding of the complex P8 branch forms,and provide visual anatomical guidance for the clinical practice of anatomical liver S8 resection;2.Intraoperative application of augmented reality navigation combined with ICG fluorescence imaging technology can help to accurately define the surgical section of S8 segment,and ensure the accurate and safe implementation of laparoscopic anatomical liver resection of S8 segment. |
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