Human liver territories: Think beyond the 8-segments scheme

Area of Science:

• Anatomy
• Surgical Interventions
• Medical Imaging

Background:

• The Couinaud system, dividing the liver into eight segments based on portal venous supply, is widely adopted globally.
• Recent anatomical, radiological, and surgical observations have increasingly reported discrepancies with the traditional Couinaud model.
• These inconsistencies highlight potential limitations in the current understanding of liver compartmentalization.

Purpose of the Study:

• To provide a viewpoint that clarifies the inconsistencies observed with the established eight-segment liver model.
• To enhance the understanding of variations in liver anatomy and vascularization.
• To offer a foundation for developing customized liver interventions based on individual patient anatomy.

Main Methods:

• Review and synthesis of existing anatomical, radiological, and surgical literature.
• Comparative analysis of reported observations against the Couinaud segmentation scheme.
• Development of a conceptual framework to explain observed discrepancies.

Main Results:

• Identification of specific anatomical and vascular variations that challenge the universal applicability of the Couinaud system.
• Explanation of how these variations can lead to misinterpretations in imaging and surgical planning.
• Demonstration of the need for a more nuanced approach to liver segmentation.

Conclusions:

• The traditional eight-segment liver model requires re-evaluation in light of emerging evidence.
• Understanding anatomical variations is crucial for accurate liver surgery planning.
• This work supports the development of patient-specific strategies for liver interventions.