Anatomical Study Of The Natural Gaps Between The Proposed "Six Gates" Based On The Laennec Capsule

Objective(s):To investigate the anatomical level of liver Laennec capsule,as well as its distribution in peripheral hepatic veins,and discuss the spatial location,characteristics of the natural gaps between "six gates" based on Laennec capsule,through field dissection of liver transplantation(LT)recipientliver,the aim of deepening the understanding of liver Laennec capsule and promoting the standardization and process of Laennec approach for anatom ic hepatectomy(LAH).Methods: Through field dissection of 19 patients undergoing allotranspla n-tation of the liver for end-stage chronic liver disease in the Department of Hepatobiliary Surgery of CALMETTE Hospital & The First Hospital of Kunming(Yunnan Liver Transplantation Research Center and Kunming Organ Transpla-ntation Center)from September 2021 to January 2023: 1.Measuring the lengthof the natural gaps between GateⅠ and GateⅡ,GateⅡand GateⅢ,GateⅠ and GateⅢ,GateⅣ and GateⅤ,GateⅤ and GateⅥ,GateⅣ and GateⅥ and the angle between the sagittal plane,coronal plane and horizontal plane,aimingto investigate the spatial location characteristics of the natural gaps;2.Histopa-thological observation was made after hematoxylineosin staining(HE staining),Masson staining and Gomori aldehyde fuchsin staining in the liver of recipient livers segment Ⅲ and Ⅴ,to observe the anatomical level of Laennec capsule and its distribution around the peripheral hepatic veins.Results: 1.There were no Glisson pedicle and liver parenchyma destroyed after connected GateⅠ with GateⅡ,GateⅡ with GateⅢ,GateⅠ with GateⅢ,GateⅣ with GateⅤ,GateⅤ with GateⅥ,GateⅣ with GateⅥ through the natural gaps between Laennec capsule and liver parenchyma.2.At the histological level,the liver parenchyma is directly covered by Laennec capsule,and there is no Laennec capsule around the peripheral hepatic veins.3.The length of the gap between GateⅠand GateⅡ is 40.1±5.3mm,and the angle between the gap and the sagittal plane is 27.47±6.15°,and the angle between the gap and the coronal plane is 27.68±3.53°,and the angle between the horizontal plane is 19.79±5.17°.4.The length of the gap between GateⅡand GateⅢ is 29.8±4.1mm,and the angle between the gap and the sagittal plane is 47.11 ± 12.94 °,and the angle between the gap and the coronal plane is 24.95±4.76°,and the angle between the horizontal plane is 20.32±5.85°.5.The length of the gap between GateⅠand GateⅢ is 36.7±6.1mm,and the angle between the gap and the sagittal plane is 43.68±7.76°,and the angle between the gap and the coronal plane is 26.89±4.27°,and the angle between the horizontal plane is 22.11±4.61°.6.The length of the gap between GateⅣ and GateⅤ is 22.7±6.7mm,and the angle between the gap and the sagittal plane is 72.58±9.35°,and the angle between the gap and the coronal plane is 26.74±6.57°,and the angle between the horizontal plane is 22.58±3.90°.7.The length of the gap between GateⅤand GateⅥ is 26.2±5.7mm,and the angle between the gap and the sagittal plane is 55.16 ± 10.34 °,and the angle between the gap and the coronal plane is 25.89±4.63°,and the angle between the horizontal plane is 21.89±6.30°.8.The length of the gap between GateⅣ and GateⅥ is 34.6±4.7mm,and the angle between the gap and the sagittal plane is 46.47 ± 14.05 °,and the angle between the gap and the coronal plane is 25.74±6.17°,and the angle between the horizontal plane is 23.89±6.40°.Conclusion(s): 1.Laennec capsule is a dense filamentous structure rich in elastic fibers,which covers the surface of the entire liver parenchyma and enters the liver parenchyma along the Glisson sheath.This study showed that Laennec capsule do not exist around the peripheral hepatic veins.2.The angle between the natural gaps and the angle between the sagittal plane is 20-80°.Therefore,if through the Laennec approach during ananatomical hepatectomy,the angle to the sagittal plane should be confirmed more carefully to avoid unnecessary liver parenchyma and vascular injury.3.In this study,the field dissection proved that the Glisson pedicle could be dissociated and controlled through the natural gaps between each gate without the liver parenchyma and the Glisson pedicle damaging.