A classification of types of hepatic vein based on data obtained from a computer-assisted surgery system and its clinical implications in liver surgery

Abstract

Objective To classify the types of hepatic vein and to measure their corresponding liver venous drainage volumes based on analysis of data obtained from a computer-assisted surgery system with an aim to provide an anatomical basis on individualized anatomical hepatectomy. Methods Thin-layer computed tomography (CT) imaging on 570 patients were reconstructed using the Hisense CAS. The types of hepatic vein were classified according to their anatomical variations. The margins of the hemilivers or sectors and their corresponding hepatic venous drainage volumes were displayed. Results The major hepatic veins were classified into three types: Type Ⅰ (270/570, 47.4%), type Ⅱ (294/570, 51.6%), and type Ⅲ (6/570, 1.0%). The left hepatic vein (LHV) was classified as type Ⅰ in 190/570 (33.3%), type Ⅱ in 79/570 (13.9%), and type Ⅲ in 301/570 (52.8%). The middle hepatic vein (MHV) was classified as type Ⅰ in 313/570 (54.9%), type Ⅱ in 174/570 (30.5%), and type Ⅲ in 83/570 (14.6%). The right hepatic vein (RHV) was classified as type Ⅰ in 456/570 (80.0%), type Ⅱ in 79/570 (13.9%), and type Ⅲ in 35/570 (6.1%). Type Ⅰ was further classified into four subtypes of A (26/456, 5.7%), B (404/456, 88.6%), C (20/456, 4.4%), and D (6/456, 1.3%). The LHV volume was (25.0±6.6)%, the MHV volume was (34.8±9.5)% and the RHV volume was (25.1±11.6)% in 63 patients with inferior right hepatic veins (IRHV). The IRHV and other branches volumes were (14.7±7.4)%. The RHV volume was (40.7±8.6)% in 68 patients without IRHV. Conclusions Hepatic venous variations are complex. Significant differences existed in the hepatic venous drainage volumes. The Hisense CAS clearly delineated the relationship between the intrahepatic vascular structures and the liver carcinoma which hopefully can lead to improvement in the success rate of complex hepatectomy. Key words: Hepatic vein; Three-dimensional reconstruction; Vascular type; Computer-assisted surgery; Liver volume