Can we delineate preoperatively the right and ventral margins of caudate lobe of the liver?

A comprehensive study and extensive review of the Caudate lobe: The last piece of "Jigsaw" puzzle

Many liver surgeons have updated their understanding of the liver in recent years because of detailed studies on the liver anatomy and the rapid advances in laparoscopic liver surgery. Despite newer approaches, concepts and methods, research on the caudate lobe continues to be based on case reports and several persistent challenges concerning caudate lobe surgery that are worth discussing. Based on the literature and the author's experience, this study considers and addresses the challenges associated with caudate lobectomy encountered by most liver surgeons. We searched PubMed for relevant articles in English for 'caudate lobe', 'cholangiocellular carcinoma', 'laparoscopic caudate resection', 'right-side boundary of the caudate lobe' and 'assessment of hepatic functional reserve' published up to May 2022. This study reviewed the anatomical history of the caudate lobe, focusing on the challenges associated with caudate lobe-related surgical resection. Due to the unique anatomical position of the caudate lobe, surgical strategy for caudate lobe resection is particularly important, and the technical requirements for hepatobiliary surgeons are also extremely strict. Therefore, understanding the anatomical history of the caudate lobe and discussing the challenges associated with caudate lobectomy is essential.

A practical study of the hepatic vascular system anatomy of the caudate lobe

Background

This study aimed to examine the inflow and outflow vascular system of the caudate lobe and determine its relevance to hepatobiliary surgery.

Methods

A total of 41 cadaveric liver specimens were dissected in 2019 to evaluate the inflow and outflow vascular system of the caudate lobe.

Results

The Glisson's pedicles of the paracaval portion were mainly from the right pedicle in 14 cases (34.15%), mainly from the left pedicle in 22 cases (53.66%), and equally from the left and right pedicle in 5 cases (12.19%). Many thick branches of the portal vein were found behind the plane consisting of the hilar plate and Arantius ligament, but none of them were thicker than 1 mm in front of the plane. All of the veins of the caudate lobe drained into the inferior vena cava (IVC) via the anterior face. There was an avascular zone without short hepatic veins (SHVs) consisting of loose connective tissue between the retrohepatic IVC and caudate lobe, with its length and width being 45-97 mm and 6-15 mm, respectively.

Conclusions

The plane consisting of the hilar plate and Arantius ligament can be regarded as the boundary between the caudate lobe and the other lobes. There is an avascular zone without SHVs consisting of loose connective tissue between the retrohepatic IVC and caudate lobe.

Landmarks to identify segmental borders of the liver: A review prepared for PAM-HBP expert consensus meeting 2021

BACKGROUND

In preparation for the upcoming consensus meeting in Tokyo in 2021, this systematic review aimed to analyze the current available evidence regarding surgical anatomy of the liver, focusing on useful landmarks, strategies and technical tools to perform precise anatomic liver resection (ALR).

METHODS

A systematic review was conducted on MEDLINE/PubMed for English articles and on Ichushi database for Japanese articles until September 2020. The quality assessment of the articles was performed in accordance with the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

A total of 3169 manuscripts were obtained, 1993 in English and 1176 in Japanese literature. Subsequently, 63 English and 20 Japanese articles were selected and reviewed. The quality assessment of comparative series and case series was revealed to be usually low; only six articles were qualified as high quality. Forty-two articles focused on analyzing intersegmental/sectional planes and their relationship with specific hepatic landmark veins. In 12 articles, the authors aimed to investigate liver surface anatomic structures, while 36 articles aimed to study technological tools and contrast agents for surgical segmentation during ALR. Although Couinaud's classification has remained the cornerstone in daily diagnostic/surgical practices, it does not always portray the realistic liver segmentation and there has been no standardization on which a single strategy should be followed to perform precise ALR.

CONCLUSIONS

A global consensus should be pursued in order to establish clear guidelines and proper recommendations to perform ALR in the era of minimally invasive surgery.