Cone Unit-Based Anatomical Liver Resection Guided by Preoperative Embolization and ICG Fluorescence: A Novel Surgical Strategy

Background: The liver cone unit (Tokyo 2020 terminology) of the peripheral portal vein territory represents the smallest anatomical and functional unit of the liver.^{1, 2} While this unit enables anatomical, subsegmental resection, particularly in patients with cirrhosis, the tumor-bearing cone unit can be challenging to identify intraoperatively.³ Patients and Methods: A 58-year-old man with hepatitis C-related cirrhosis (Child–Pugh B) was diagnosed with a subcapsular hepatocellular carcinoma (HCC) in segment 8. While ablation can achieve excellent outcomes in small HCC, owing to the superficial- (risk of seeding) and posterior-superior location (possible transdiaphragmatic access) as well as the presence of ascites, resection was offered. Preoperative three-dimensional (3D) reconstruction identified the tumor-bearing cone unit. Owing to cirrhosis-related shunting with its impact on Indocyanine Green (ICG) tumor staining, selective artery embolization of the branch feeding the neighboring cone unit and subsequent ICG injection into the tumor bearing cone unit was performed.^{4, 5} This allowed for laparoscopic, anatomical ICG-guided resection along the tumor-bearing cone unit’s boundaries. Results: Cone unit-based planning and targeted embolization enabled accurate localization and resection of the tumor-bearing area. Despite impaired ICG uptake due to cirrhosis, fluorescence imaging provided visualization for precise anatomical transection with minimal bleeding. Conclusions: This case demonstrates a novel combined interventional radiology/surgical approach for precise cone unit resection, leading to minimal intraoperative blood loss and function-preserving hepatectomy in a patient with advanced cirrhosis. This conceptional framework can serve as a complement to ultrasound guided cone unit identification in patients with advanced cirrhosis, which can be highly challenging intraoperatively.