Analysis of Essential Liver Anatomy for Anatomical Segmentectomy 8: A Proposal for the Hybrid Glissonean Approach.

Abstract

Anatomical segmentectomy 8 is challenging owing to the complex branching patterns and position of the Glissonean pedicle of segment 8 (G8) root. The hepatic vein-guided approach and extrahepatic Glissonean approach are essential for accurate G8 root identification. We evaluated the key anatomical factors for precise G8 root transection and proposed the hybrid Glissonean approach (HYBA) as a potential surgical strategy. Using high-quality multidetector-row computed tomography (CT) images from 73 living liver donor candidates, we assessed the position of the segment 8 portal vein (P8) root relative to the middle hepatic vein (MHV), intersegmental vein between segments 5 and 8 (IV5/8), and hepatic hilum. Distances from the MHV-IV5/8 confluence and alignment with the MHV/right hepatic vein (RHV) plane were also analyzed. IV5/8 was not identified on CT in 9.6% of cases. In 61.6% of cases, the P8 root aligned with the MHV-RHV plane. Additionally, in 53.4% of cases, the shortest distance from the P8 root to the MHV matched the MHV-IV5/8 confluence. The distance from the MHV-IV5/8 confluence to the P8 root (5.8-32.5 mm), the first branch of the right anterior portal vein to the P8 root (3.9-39.4 mm), and the shortest distance from the MHV to the P8 root (5.1-28.9 mm) showed significant variation. This study highlights anatomical variations in the positional relationships of the G8 root with key landmarks (MHV, RHV, IV5/8, and hepatic hilum). Preoperative evaluation of these factors is crucial for selecting the optimal approach, and HYBA has been proposed as a viable option.