Conceptual framework of middle hepatic vein anatomy as a roadmap for safe right hepatectomy

Background: While the middle hepatic vein (MHV) guides parenchymal transection during right hepatectomy, its most proximal tributaries can be difficult to identify, and injury to its tributaries can be a source of major bleeding. Method: Following simulation modeling of right hepatectomy, reconstructed MHV data was pooled from 40 patients. MHV-tributaries and MHV-relationship to the portal pedicle were mapped out to facilitate their identification from the beginning of parenchymal transection. Results: Hotspots for injury were identified: A median of 1 (1-3) tributaries draining segment 5 (V5) were within 45-90mm from the MHV termination, and 16mm above and 22mm caudal to the portal trunk. Simulation demonstrated a constant anatomic relationship between portal pedicle and the proximal MHV. A median of 2 (0-4) tributaries draining segment 8 (V8) were located 9-35mm from the MHV termination. This information was compiled into an MHV-road-map demonstrating 86% of the MHV tributaries at risk for significant bleeding are within 15mm of the MHV, while only thin tributaries are located in the outer area. Conclusions: The MHV-road-map led to a peripheral-to-central parenchymal transection approach to minimize the risk of MHV-injury thereby reducing bleeding during open and minimally invasive right hepatectomy.