Reevaluation of rats' hepatic vascular anatomy - getting ready for ALPPS model

Background: Associating Liver Partition with Portal Vein Ligation for Staged Hepatectomy (ALPPS) is a surgical strategy which induces a rapid regeneration of the future liver remnant (FLR). Regeneration seems to be faster than after classical PVL. However, the underlying mechanism is not yet investigated. Therefore we did a detailed anatomical study to clarify the anatomy of the portalvein and median hepatic vein of rats as a prerequisite to develop a surgical model. Method: Reevaluation of the detailed vascular anatomy of ML was per-formed. 10 explanted livers were subjected to imaging techniques after microfilm injection. 3D reconstruction was performed in order to visualize the spatial distribution of the vascular branches of portal vein and hepatic vein. Result: Similar to the human liver, the ML was supplied by the right median and left median portal branches (RMPB and LMPB) and the parallel hepatic arterial branches. The ML was drained by 3 main branches: right median, middle median and left median hepatic vein (RMHV, MMHV and LMHV). The main bifurcation of MMHV was located in RML, draining not only the middle portion of ML, but also the anterior portion of LML. However, the spatial distribution of the branching pattern was subject to some variations potentially influencing the size of the territory at risk of outflow obstruction. Conclusion: According to our anatomical study, it seems better to perform transection along the umbilical fissure in rats, although it can cause outflow obstruction of anterior portion of LML. In this case, a resection of the anterior portion of LML could be discussed.