Anatomical Variations of Portal Vein Branches in Subsegment IVb: A 3D Reconstruction-Based Classification to Inform
Xiang Zhao1, Kaiju He1, Lucui Qin2
1Department of General Surgery, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Biliary Tract Disease Research, Shanghai, China.
The Journal of Surgical Research
|April 19, 2026
Summary
This study reveals a new four-type classification for the complex portal venous anatomy of liver segment IVb (S4b). This anatomical framework aids surgeons in planning precise resections for gallbladder cancer, improving patient outcomes.
Area of Science:
- Hepatobiliary Surgery
- Vascular Anatomy
- Medical Imaging
Background:
- Gallbladder cancer resection requires complete removal of segment IVb (S4b).
- The portal venous anatomy of S4b is complex and varies significantly between individuals.
- Existing classifications inadequately describe S4b's portal venous supply.
Purpose of the Study:
- To systematically characterize the portal vein anatomy supplying S4b using 3D visualization.
- To develop a practical anatomical classification for S4b's portal vasculature.
- To inform preoperative planning for radical gallbladder cancer surgery.
Main Methods:
- Retrospective analysis of 115 patients' CT scans.
- 3D reconstruction of the portal venous system.
- Analysis of S4b's supplying portal vein branches' origin, number, course, and common trunk patterns.
Main Results:
- S4b receives 1-6 portal vein branches, typically from the left portal vein's umbilical portion.
- A four-type classification (A, B, C, D) based on common trunks supplying S4a/S4b was established.
- 73% of patients had 1-2 common trunks, with diameters correlating to their number.
Conclusions:
- The proposed four-type classification systematizes S4b portal venous anatomy.
- This classification aids in preoperative planning for gallbladder cancer surgery.
- Optimized surgical planning improves procedural safety and oncologic outcomes.
