Atypical origin of the common hepatic artery.

INTRODUCTION

Anatomical variations of the hepatic artery are commonly found during radiological examinations and abdominal operations[1,89] It is estimated that the variation index reach 45% of the population[8]. The significant prevalence gives this type of variation major medical importance, and justifies the surgeon know it to avoid iatrogenic injury.

The usual blood vessel anatomy is the common hepatic artery ascend from the celiac trunk[8]; however, this arrangement may change due to embryonic variations. These variations, from most to least frequent are: 1) the right hepatic artery ascend from the superior mesenteric artery; 2) the left hepatic artery ascend from the left gastric artery; 3) the two events occur simultaneously; and 4) the common hepatic artery ascend from the superior mesenteric artery.

In this article, is reported the occurrence of the fourth situation. According to the literature, there is no consensus on the criteria for designation of this variation. Therefore, it can be described in two ways: consider it a hepatomesenteric trunk - giving rise to the superior mesenteric artery and common hepatic artery - or it can be said that the common hepatic artery arises as a branch of the superior mesenteric artery.

The objective of this paper is to present a case and emphasize the prevalence of anomalous positions of the hepatic arteries and their possible implications.

CASE REPORT

It was observed in a male corpse, common hepatic artery originating from the superior mesenteric artery, located 3.5 cm lower and lateral from the celiac trunk, forming a hepatomesenteric trunk. The other branches of the celiac trunk were normal and exhibited the typical path (Figure 1).

Figure 1

A) Photograph of the abdominal cavity of the corpse with some vessels in evidence: the left renal vein (double arrow), celiac trunk (single arrow) and the hepatomesenteric trunk (indicated by *); B) illustration of the same photo, highlighting the hepatomesenteric trunk (indicated by *).

DISCUSSION

Variations of the hepatic artery have embryological basis[10]. During intrauterine development, there is the formation of four ventral splanchnic vessels, connected by a ventral longitudinal anastomosis. With the maturation of these, the two central roots degenerate. Thus, the first and fourth roots which form respectively the celiac artery and superior mesenteric artery anastomoses remain. If the separation between them occurs at different level of the standard pattern, any vessel in the celiac trunk can be shifted to the superior mesenteric artery. This situation appears in this case report: with the anomalous roots separation, there was formation of a hepatomesenteric trunk and other gastrosplenic.

Several studies[1,2,3,4,5,6,7,8,9,10,11] report different variations. The most representative of them is to Hiatt et al.[5] with a sample of 1000 people. The variation here presented (common hepatic artery + superior mesenteric artery) is of uncommon occurrence with an average of 2%. This value agrees well with the values ​​found in other articles, ranging from 1.6% to 3.5%.