Celiac Trunk and Hepatic Artery Variants in Pancreatic and Liver Resection Anatomy and Implications in Surgical Practice

Importance of Anatomical Variation of the Hepatic Artery for Complicated Liver and Pancreatic Surgeries: A Review Emphasizing Origin and Branching

Knowledge of anatomical variations of the hepatic artery from its origin to intrahepatic segmentation is of utmost importance for planning upper abdominal surgeries including liver transplantation, pancreatoduodenectomy, and biliary reconstruction. The origin and branching pattern of the hepatic artery was thoroughly described by the classification of Michels and Hiatt. Some rare variations of the hepatic artery were classified by Kobayashi and Koops. By the use of the multidetector computed tomography (MDCT) technique, the branching pattern of the hepatic artery can be visualized quite accurately. Unawareness of these arterial variations may lead to intraoperative injuries such as necrosis, abscess, and failure of the liver and pancreas. The origin and course of the aberrant hepatic arteries are crucial in the surgical planning of carcinoma of the head of the pancreas and hepatobiliary surgeries. In liver transplant surgeries, to minimize intraoperative bleeding complications and postoperative thrombosis, exact anatomy of the branching of the hepatic artery, its variations and intrahepatic course is of utmost importance. This review discusses variations in the anatomy of the hepatic artery from its origin to branching by the use of advanced imaging techniques and its effect on the liver, pancreatic, biliary and gastric surgeries.

Prevalence of hepatic vascular anomalies in consecutive contrast-enhanced computed tomography images — a retrospective observational study

Background

Liver is a complex, highly vascular organ, where anatomical variations are the norm. This study aimed to analyze all the three hepatic vascular anatomical variations in a single study which would help us understand the prevalence of hepatic vascular (arterial, portal, venous) anomalies in the population catered to by our institution.

Methods

A retrospective analysis of 545 contrast-enhanced CT scans was done from November 2019 from the institute PACS after satisfying the inclusion and exclusion criteria. The raw imaging data were processed in PACS software — Centricity™ Universal Viewer and Syngo.via Vb20 platform, for axial, coronal, and axial-oblique multiplanar reformation, maximum intensity projection (MIP), and volume rendering (VR) images. Data were analyzed in the three vascular phases to determine the anatomical variations. Analysis was done by two surgical residents in the division of HPB surgery, which was verified by a certified radiologist.

Results

There were no major differences in the prevalence rates of the vascular anomalies across gender and domicile distributions. The prevalence of normal hepatic artery and variant hepatic artery in our study was 69% and 31%, respectively. Accessory left hepatic artery (10%) was the most common hepatic artery variant in our study. Single RHV was seen in 77.4%, and other RHV variants like two RHV with common trunk, two RHV with independent drainage, and three RHV with common trunk contribute 22.6% of our study population. Accessory inferior RHV was seen in 19.8% of the study population. Normal portal vein anatomy was found in 81.1% in our study, and the most common variant in our study population was trifurcation of portal vein (16.1%).

Conclusion

This was the largest study until date from South India, studying all three hepatic vascular anatomical variations in a single study. Variations in the anatomy of hepatic arteries, portal veins, and hepatic veins are common. A good knowledge of the same is necessary especially for a hepatobiliary surgeon or for an interventional radiologist, to plan and avoid complications during a procedure. Preoperative contrast-enhanced CT scan and whenever necessary a VR or a MIP reconstruction will precisely help in identifying these variations.

A Rare Anatomic Variant of Double Replaced Hepatic Arteries: A Case Report and Brief Review of the Anomalous Hepatic Vasculature Literature

BACKGROUND The liver is a frequent site of surgical resection for both benign and malignant lesions. Advanced knowledge of the hepatic arterial system and its variants is crucial to avoid incidental injuries during a resection procedure. Many variants have been previously described in the literature, yet extremely rare cases continue to be encountered in clinical practice. Documentation of these variants can thus allow for proper preoperative procedural planning when considering interventions involving the liver. Our aim is to present one such unique and extremely rare anomaly. CASE REPORT During routine cadaveric dissection of a 78-year-old man who had died of acute myeloid leukemia, a rare anatomic variant of the hepatic vasculature was revealed: a replaced right hepatic artery (rRHA) coming directly from the celiac trunk, a middle hepatic artery (MHA) continuing from the common hepatic artery (CHA), and a replaced left hepatic artery (rLHA) branching from the left gastric artery (LGA). To the best of our knowledge, this anomaly has only been described once before in the literature. CONCLUSIONS We report a rare anatomical variant of the hepatic vasculature. The significance of this variant must be considered during preoperative planning and the intra-arterial infusion of targeted drugs. This case further emphasizes the importance of proper medical imaging and documentation to ensure the best course of treatment for each patient. Given that this variant has only so far been identified in 2 post-mortem subjects, further work should include attempts at characterizing its physiologic effects in a living patient.