A Study on Variation of Origin of Gastroduodenal Artery

Aim: The aim of the study is to note the variation in the origin of Gastroduodenal artery (GDA). In a study done on 30 cadavers at Seth G.S. Medical College and K.E.M. Hospital, Mumbai, India, during the period 2011–2012, it was found that there was a rare type of branching pattern of the gastroduodenal artery (GDA). The knowledge of variations is very important during the operative, diagnostic and endovascular procedures. Variations in the branching pattern of the cystic artery often occur and may be encountered during cholecystectomy or laparoscopic cholecystectomy and hepatobiliary surgeries. This study describes unusual origin of cystic artery from the gastro duodenal artery as found during routine dissection in a cadaver. The embryological development and clinical importance of such a variation have been emphasized. Original Research Article Gawali et al.; JPRI, 33(64B): 391-394, 2021; Article no.JPRI.71276 392


INTRODUCTION
The gastroduodenal artery emerges posterior and superior to the first part of the duodenum from the common hepatic artery. At the lower boundary of the first part of the duodenum, it gives rise to the right gastroepiploic and superior pancreaticoduodenal arteries.
It runs between the initial half of the duodenum and the pancreas' neck, just to the right of the peritoneal reflection from the duodenum's posterior side. It is normally to the left of the main bile duct, however it might be anterior on occasion.
It separates into the right gastroepiploic and superior pancreaticoduodenal arteries at the lower border of the first half of the duodenum. The artery's lowest part gives rise to small branches that supply the pyloric end of the stomach and the pancreas, as well as retroduodenal branches that directly supply the first and proximal portions of the second parts of the duodenum. Although the gastroduodenal artery normally arises from the common hepatic artery, it can also develop from a trifurcation of the right and left hepatic arteries, the superior mesenteric artery or the left hepatic artery (rarely), or the coeliac axis or right hepatic artery (rarely).
The gastroduodenal artery frequently develops behind the upper border of the first part of the duodenum and supplies the superior aspect of the first part [1].
Cystic artery usually arises from the right hepatic artery. During hepatobiliary surgeries and cholecystectomy, uncontrolled bleeding from the cystic artery and its branches is a serious problem that may occur due to inadvertent damage to the vessel due to unknown variation. Due to bleeding laparoscopic cholecystectomy may get converted to open cholecystectomy. It is said that anatomical variations in the hepatic arterial supply are due to variant embryological development of the ventral arteries of the foregut and failure of these vessels to regress [2,3,4].
A complete knowledge of these variations in branching pattern is clinically important in liver transplantation, cholecystectomy, hepato biliary surgeons and also for radiologists. Variations in the origin of cystic artery may predispose to iatrogenic injury during surgical procedures.

MATERIALS AND METHODS
30 embalmed cadavers were meticulously dissected in the department of anatomy, Seth GSMC, Mumbai. Coeliac trunk was dissected and branches of coeliac trunk were traced. Common hepatic artery and its branches were followed and origin of gastroduodenal was traced and variations in origin were noted.

RESULTS
During dissection of 30 embalmed cadavers at Seth G.S. Medical College and K.E.M. Hospital, Mumbai, it was found that gastro duodenal artery was originating from common hepatic artery in 29 (96.66%) cases but in 1 (3.33%) case gastro duodenal artery arose from right hepatic artery.
Common hepatic artery (CHA) originated from coeliac trunk which later divided into right and left hepatic artery. Gastroduodenal artery originated from right hepatic artery (RHA). RHA then went on to supply the liver and it also formed Moynihan's hump. While cystic artery originated from gastroduodenal artery outside the Calot's triangle and it then did ascend upwards to supply gall bladder. Right hepatic artery did not give any branch to gall bladder in the Calot's triangle (Fig.  1). This is a very rare case where gastroduodenal and cystic arteries had variation in origin.

DISCUSSION
There are many classifications of variations of celiac and hepatic artery. Most commonly used is Michels et al who has classified the anomalies into ten types [5]/ Song et al. described series of celiac and hepatic artery variations in 5002 patients using CT scan and digital subtraction angiography [6].
During development, the extrahepatic biliary system arises from an intestinal diverticulum, which carries a rich supply of vessels from the aorta, coeliac trunk and superior mesenteric artery. Later most of these vessels are absorbed, leaving in place the mature vascular system. As the pattern of absorption is highly variable, it is not unusual for the cystic artery and its branches to derive from any other artery in the vicinity [9][10][11].
The preferred method of gall bladder removal is laparoscopic cholecystectomy. The surgeon must have a detailed anatomical understanding of the probable changes in the anatomy of the cystic artery and its branches during laparoscopic cholecystectomy since dissection of a limited field is magnified on the video monitor. The cystic artery that arises outside the hepatobiliary triangle usually passes ventral to the common hepatic duct, and in some cases it may even be inferior to the cystic duct, making it the first structure encountered during laparoscopic dissection of the inferior border of the hepatobiliary triangle, with the risk of injury. It is self-evident that closure of a cystic artery too close to the common hepatic duct would jeopardise it [12][13][14][15].

CONCLUSION
Knowledge of such variation has surgical importance and requires special attention in gallbladder surgeries as well as pancreatic surgeries and also helps the radiologist to perform an intraoperative cystic angiogram during hepatobiliary surgery.

CONSENT
It is not applicable.

ETHICAL APPROVAL
It is not applicable.