Hepatic vein anatomy related to Laennec's capsule for liver resection

Laennec's capsule is the proper membrane covering the entire surface of the liver parenchyma, including around the Glissonean pedicles and hepatic veins. Laennec's capsule around the hepatic veins has been clinically reported to comprise two layers: the hepatic and cardiac Laennec's capsules. However, where the cardiac Laennec's capsule is derived from and the two capsules' separability are still unclear. This study aimed to investigate the anatomy of the two capsules using cadaveric specimens.Histopathological examinations of autopsy specimens from four cadavers were conducted. Each specimen was sliced in the longitudinal section to include the pericardium, right hepatic vein (RHV), and inferior vena cava (IVC). Additionally, long-axis specimens of the RHV were obtained to determine the separability of the capsules and to examine the extent to which the capsules extended along the RHV. Laennec's capsule was estimated using elastic fiber staining.The cardiac Laennec's capsule is derived from the pericardium (parietal and visceral) and diaphragm and runs parallel with the IVC and hepatic veins associated with the hepatic Laennec's capsule. The two capsules were separable micro- and macroscopically. The hepatic Laennec's capsule was observed from the root to the peripheral side and the cardiac Laennec's capsule from the root to the middle side of the hepatic vein.The existence of the two layers of Laennec's capsule around the hepatic veins was confirmed histologically and they were separable. Identification and decollement of these layers would contribute to establishing safe and feasible anatomic liver resection techniques.