Purpose: Studies of liver anatomy have developed alongside clinical achievements, as these types of research complement each other. The aim of this study is to determine whether or not the portal vein branches (P4d) in 'Nagino's trisectionectomy' exist, and to examine their characteristics using cadaver dissection.
Methods: From April 2012 to July 2012, 31 adult cadavers were delicately dissected. We defined a 'NewGP' as an extra glissonian pedicle (GP) other than the traditional GPs that supply segments II, III, IVa, and IVb in the ordinary direction, and anatomically located superior to the umbilical fissure (UF).
Results: We identified 'NewGPs' based on the UF and UF vein. The incidence of 'NewGPs' was 30/31 (96.8%). The diameter of the 'NewGPs' ranged from 3.5 to 5.6 mm, which was not significantly different from that of traditional GPs (II-, III-, or IV-GP), which have diameters ranging from 3.7 to 9.7 mm.
Conclusion: We think that the P4d in 'Nagino's trisectionectomy' correspond to the 'IVa NewGP' and the additional pedicle. We believe the clinical significance of the 'NewGP' is to complement the traditional II, III, IVa, and IVb pedicles in supplying the liver.
Keywords: Anatomy; Glissonian pedicle; Liver.