ICG-Enhanced Visualization of Venous Congestion for Laparoscopic Anatomical Liver Resection of Segment 8-Ventral

The portal vein branching pattern in the right anterior section (RAS) shows frequent variations. In such cases, Hjortsjö's classification¹-which divides RAS into ventral and dorsal parts^2,3-is often more appropriate than Couinaud's classification, which separates RAS into cranial (S8) and caudal (S5) parts.⁴ However, anatomical resection of the ventral or dorsal part is technically demanding, as the ventral-dorsal boundary is difficult to identify laparoscopically due to the lack of surface landmarks.

The ventral-dorsal boundary can be identified by referring to hepatic venous anatomy, as the course of a hepatic vein branch (V8) generally corresponds to this intersegmental plane.^2,5,6 Furthermore, venous congestion induced by temporary occlusion of the middle hepatic vein (MHV) corresponds to this boundary and can be visualized using indocyanine green (ICG) fluorescence.^7,8 RESULTS: A man in his 60s presented with recurrent hepatocellular carcinoma, including a 20-mm lesion at the S4/S8 border and a 10-mm lesion near the umbilical portion of S4. S4 plus S8-ventral resection was performed laparoscopically, while preserving the MHV. After transecting the G4 pedicles, the MHV trunk was exposed from the left side and temporarily clamped. The congestion area was visualized by intravenous ICG injection, and the congestion border served as a guide to the ventral-dorsal boundary. Parenchymal transection was completed along the ventral side of the MHV and V8.

Integration of hepatic venous anatomy, congestion mapping, and ICG fluorescence enables identification of the ventral-dorsal boundary and facilitates safe and precise anatomical resection of segment 8-ventral.