A Computed Tomographic angiogram (CTA) of the visceral
arteries was done in a 58 year old male with multi-detector
(640 slices) Cannon- Aquilion one CT machine at Department
of Radiology, National Hospital Colombo. The angiogram
showed the following variations.

Questions
1. What are the variations seen in the coeliac and
mesenteric arterial system in the image?
2. What is the surgical significance of the above
variations?
Answers
1. What are the variations seen in the coeliac and
mesenteric arterial system in the image?
Celiac axis is the first ventral branch of the abdominal aorta. It
usually gives rise to the common hepatic, splenic and the left
gastric artery. Common hepatic artery bifurcates into left and
right hepatic arteries. This standard hepatic arterial anatomy is
seen only in 55-80 % of the population where as in others
normal anatomical variants are encountered [1, 2].
The following variations were observed in the image above.
a) The left hepatic artery (LHA) is originating from the
left gastric artery (LGA).
b) The LGA had an abnormal origin as a direct branch
from the abdominal aorta proximal to the origin of
the abnormal celiac axis.
c) The right hepatic artery (RHA) is originating from the
superior mesenteric artery (SMA).
d) The celiac axis (CA) shows an abnormal branching
pattern. CA divides into the splenic artery (SA) and
the pancreaticoduodenal (PDA) artery i.e.
“Pancreatico-splenic trunk” (PST). Thus, CA does
not contribute to the hepatic arterial supply of this
patient.
e) The PDA which shows very tortuous course gave
origin to the right gastric artery (RGA) as its terminal
branch.
2.What is the surgical significance of the above variations?
A replaced RHA is seen in 5-21% of the population [1,2]. A
replaced LHA is seen in 2- 10% of the population [1,3].
Having knowledge about these anatomical variations is
important when making clinical decisions and during
interventions because missing to recognize above variations
can result in disasters.
For example in the case described above, accidental ligation
of the LGA results in ischemia of the left lobe of the liver
because the LHA originates from the LGA. Similarly during
liver resections difficulty in identifying the variations can
result in difficulties and accidental injuries to the hepaticarteries. Similar difficulties can occur in endovascular
procedures and following hepatic vascular trauma. Therefore
awareness of such variations is necessary to prevent
complications.