Ramification of Glisson's sheath peripheral branches and clinical implications in the era of local ablation therapy

Color Doppler Intraoperative Ultrasonography Evaluation of Hepatic Hemodynamics for Laparoscopic Parenchyma-Sparing Liver Resections

BACKGROUND

Tumors involving the hepatic veins at the hepatocaval confluence often require major or extended hepatectomies. Color Doppler intraoperative ultrasonography (CD-IOUS) evaluation of liver hemodynamics to assess congestion in the veno-occlusive parenchyma provides real-time information helpful in parenchyma-sparing surgery (PSS). This study evaluated the feasibility of CD-IOUS in patients undergoing laparoscopic liver resections for such tumors and its capacity to allow PSS.

METHODS

Consecutive patients undergoing laparoscopic liver resection for tumors at the hepatocaval confluence requiring resection of at least one hepatic vein between January 2010 and August 2020 were included. Patients were divided in 3 groups: (A) patients not assessed with CD-IOUS because it would not change the scheduled operation; patients assessed with CD-IOUS and treated with (B) PSS and (C) no-PSS. Portal blood flow in the veno-occlusive parenchyma was assessed using CD-IOUS at baseline and after clamping the concerned hepatic vein.

RESULTS

The study included 43 out of 47 patients with tumors at the hepatocaval confluence. There were 19 patients in group A. Among patients assessed with CD-IOUS, the resection of 26 hepatic veins was planned: 25 were resected, and 1 was spared. Group B included 22 patients treated with PSS, whereas group C included 2 patients with resection of all veno-occlusive parenchyma. No postoperative mortality or major morbidity was observed. The median length of hospital stay was 5 days.

CONCLUSIONS

Selected patients with tumors involving the hepatocaval confluence can be safely approached using laparoscopy. CD-IOUS evaluation of the veno-occlusive area can increase the success rate of PSS.

Human liver segments: role of cryptic liver lobes and vascular physiology in the development of liver veins and left-right asymmetry

Couinaud based his well-known subdivision of the liver into (surgical) segments on the branching order of portal veins and the location of hepatic veins. However, both segment boundaries and number remain controversial due to an incomplete understanding of the role of liver lobes and vascular physiology on hepatic venous development. Human embryonic livers (5-10 weeks of development) were visualized with Amira 3D-reconstruction and Cinema 4D-remodeling software. Starting at 5 weeks, the portal and umbilical veins sprouted portal-vein branches that, at 6.5 weeks, had been pruned to 3 main branches in the right hemi-liver, whereas all (>10) persisted in the left hemi-liver. The asymmetric branching pattern of the umbilical vein resembled that of a "distributing" vessel, whereas the more symmetric branching of the portal trunk resembled a "delivering" vessel. At 6 weeks, 3-4 main hepatic-vein outlets drained into the inferior caval vein, of which that draining the caudate lobe formed the intrahepatic portion of the caval vein. More peripherally, 5-6 major tributaries drained both dorsolateral regions and the left and right ventromedial regions, implying a "crypto-lobar" distribution. Lobar boundaries, even in non-lobated human livers, and functional vascular requirements account for the predictable topography and branching pattern of the liver veins, respectively.

Human liver territories: Think beyond the 8-segments scheme

Worldwide, compartmentalization of the human liver into portal venous territories today follows the eight-segments scheme credited to Couinaud. However, there are increasing reports of anatomical, radiological and surgical observations that contradict this concept. This paper presents a viewpoint that enhances understanding of these inconsistencies and can serve as a basis for customized liver interventions. Clin. Anat. 30:974-977, 2017. © 2017 Wiley Periodicals, Inc.

Concepts for Liver Segment Classification: Neither Old Ones nor New Ones, but a Comprehensive One

Concepts dealing with the subdivision of the human liver into independent vascular and biliary territories are applied routinely in radiological, surgical, and gastroenterological practice. Despite Couinaud's widely used eight-segments scheme, opinions on the issue differ considerably between authors. The aim of this article is to illustrate the scientific basis for understanding and harmonizing inconsistencies between seemingly contradictory observations. Possible clinical implications are addressed.