Segmental branching pattern of the left portal vein: Anatomical characteristics and clinical implications.

The existing knowledge on anatomy of segmental branches of left portal vein (LPV) is limited. This study aims to describe the surgical anatomy and variations of LPV and its segmental branching pattern. Forty fresh cadaveric liver dissections were performed. The dissection of LPV was carried out from its emergence at the level of the portal vein bifurcation to its segmental branches penetrating the left hemiliver. LPV characteristics, the number, and situation of its segmental branches were recorded. LPV comprises two portions: a 28 ± 6.7 mm-long transverse portion (TPLPV) and a 34.9 ± 4.4 mm-long umbilical portion (UPLPV). Mean number of LPV branches to segments I, II, III, and IV was 2 ± 1 (1-6), 2 ± 1 (1-4), 2 ± 1 (1-5), and 8 ± 2 (4-14), respectively. A single large vein supplied segment II in 90% of the cases. Segment III constantly had one vein arising from the left horn of UPLPV with mean diameter of 5.9 ± 1.6 mm. Most of the veins to segment IV took origin from the right horn of UPLPV with a mean number of 5 ± 2 (2-8). Segmental veins arising from UPLPV and TPLPV and supplying segment IV were present in 90 and 45% of the cases respectively. Segmental veins arising from LPV are often multiple and variable in position. Detailed knowledge of these veins is mandatory in order successfully perform anatomical liver resections or monosegment graft harvest for pediatric liver transplantation. Clin. Anat. 31: 1122-1128, 2017.