How-I-do-it: laparoscopic left medial sectionectomy utilizing a cranial approach to the middle hepatic vein and Laennec's capsule.

Background: Laparoscopic anatomic liver resection is technically demanding, given the need to safely isolate the Glissonean pedicles and expose the hepatic veins (HVs) on the liver parenchyma cut surface. Laennec's capsule is observed around the Glissonean pedicles and root of the HVs. However, its existence, particularly on the peripheral side of the HVs, remains controversial. Herein, we describe Laennec's capsule-related histopathological findings around the HVs and a safe laparoscopic left medial sectionectomy utilizing Laennec's capsule.

Methods: The extrahepatic Glissonean approach was performed by connecting Gates II and III, in accordance with Sugioka's Gate theory. Liver parenchymal transection commenced along the demarcation line, which is between the medial and lateral sections, and the G4 was dissected during transection. Subsequently, via the outer-Laennec approach, the middle hepatic vein (MHV) was exposed from the root side in cranial view, while Laennec's capsule was preserved. Parenchymal transection was completed while connecting the MHV with the demarcation line. We obtained the membrane surrounding the HVs and performed histopathological examinations.

Results: Six patients underwent laparoscopic left medial sectionectomy from February 2012 to November 2020. There were no cases involving complications (Clavien-Dindo classification; grade II or higher), open-surgery conversion, transfusion, or surgery-related death. The histopathological findings showed Laennec's capsule surrounding both the trunk of the major HVs and the peripheral side of the HVs.

Conclusions: A cranial approach to the major HVs utilizing Laennec's capsule is a feasible and advantageous procedure for laparoscopic left medial sectionectomy. We propose that Laennec's capsule surrounds the entire length of the HVs.