Introduction

For several years, the anatomy of the biliary system has been the focus of prolonged research. ^[1] In cholecystectomies, primarily because of their surgical significance and the simplicity at which they can be examined. The extrahepatic biliary apparatus consists of a blind end diverticulum formed by hepatic ducts, gall bladder, common bile duct (CBD), and cystic duct. ^[2] Gall Bladder flask located in contact with the lower surface of the right liver lobe. The length is between 7-10 cm in adults with a potential of up to 50 ml. ^[3] The bile is extracted by the further hepatic biliary tract from the liver and drained into the second portion of the duodenum. It is notable for its distinctions. Intrahepatic union of right and left hepatic ducts, peripheral, various ways of end of the normal duct; hepatic, cystic and common bile are common variants. ^[4] Intrahepatic union of right and left hepatic ducts, closure of cystic duct on the left side of the typical bile duct and accessory hepatic ducts are the differences in this study. There are no medical emergencies with typical human anomalies in this area, but after surgeries in this area, it can cause serious complications. ^[4]

One of the utmost common sites for surgical operations is the extra-hepatic biliary system. In this method, the occurrence of anatomical differences is stated to be as low as 7.3% to as high as 47%. Popular biliary system and gallbladder disorders involve differences in the number and position of the gallbladder. ^[5] Multiple gallbladders may also have different cystic ducts, or one cystic duct may be shared by two or more. These additional gallbladders can lie below the liver's right or left lobe or inside the gastrohepatic ligament or liver. They may emerge from the hepatic duct, the CBD, or the right or left hepatic duct. In certain examples, however; the gallbladder, cystic duct, or connection of cystic duct and CBD is reached by a different conduit from the liver. These ducts have been known as the ducts of Luschka. These extra ducts should be treated during laparoscopy by ligation, suture, cutting, cauterization, or removal when they are detected. ^[6]

The purpose of the research was to observe the anatomical differences in Indian cadaveric specimens in the extrahepatic biliary system. This is the first research in our area to address the anatomical differences of the extra-hepatic biliary system, according to our interpretation.

Subjects and Methods

On 100 embalmed adult cadavers of either sex, a retrospective and observational analysis were conducted. The research period in the Department of Anatomy, Mata Gujri Memorial Medical College, Kishanganj, Bihar ranged from 2014-2020. Included in the collection of specimens were those from unclaimed and accepted bodies formally collected by the Department of Anatomy. For the intent of dissection, the corpses were first embalmed inside the lab. The omission of cadavers with decomposed mutilated bodies and others with malignancies.

Dissection and processing:

From the xiphoid process to the pubic symphysis, the anterior abdominal wall was incised and unlocked layer by layer. The peritoneum was unlocked and the viscera was properly removed from the field of view and washed. Each portion was traced proximally and distally from the extrahepatic biliary apparatus. Relevant information was registered. Gallbladder and information, followed by cystic duct and its associated cystic artery, were identified and noted. It tracked the cystic duct to its connection with the popular hepatic duct. They then dissected and delineated the typical bile duct. Cystic duct length and angulations have been observed. Popular bile duct duration and difference, if any, were noted. The common hepatic duct was then traced caudally until its branching and period were noted.

Results

In our study of 100 cases, 70 were male 30 were females.

The size of the gall bladder observed among the participants in the sample was represented in the above table. The smallest measured gall bladder was about 25ml, while the largest observed gall bladder was about 120ml. Our analysis reported approximately 50 ml of gall bladder on average.

Congenital anomalies of the gall bladder were recorded in above table 2. The current study recorded one each case of absence of anomaly, Intrahepatic, Double, Bilobed and with separate mesentery.

Our study observed pathologies in the gall bladder. The maximum cases were recorded for Pathological findings, accounting for 20% of total cases. Around 12 cases of Cholelithiasis were also recorded. Further, around 4 and 3 cases of Adhesion & Thickening and Choledocholithiasis, respectively were also noted. A solitary pathology involving carcinoma was noted.

From the above table, it can be inferred that the maximum extent (75%) of peritoneal investment of gall bladder was recorded in 2/3 to 3/4. This was surveyed by 13% in extra than 3/4. And, lastly, around 12% of cases showed Less than 2/3 of peritoneal investment of gall bladder.

[Table 5] shows the relation of the fundus of the gall bladder with the anterior margin of the right lobe of the liver. In our study, we observed maximum cases (n=60) showing the level of fundus – Inframarginal. This was followed by Level of fundus – Marginal showing around 25% cases. The least cases of Level of fundus – Supramarginal were recorded at 25%.

Of the 100 cadavers studied, the anatomic positions of bile ducts were standard in the collective hepatic duct right and left. We assessed the diameter and length of various ducts in EBHA. As noted in the above table, the average length of hepatic ducts in this research study was shorter when compared to that of the standard range. Whereas, the average diameter of hepatic ducts in this current study was greater when compared to that of the standard range.

A total of 19% of specimens having additional ducts were noted. Out of which, 14% were AHD Single Type and the remaining 5% were AHD Complex Type.

Normal angle was observed in 62% of the cases. Whereas, eight variations of the hepatocystic junction were observed in our samples. The first variation is represented by the Right side of CHD in 80% of cases. This was followed by a Parallel course, Anterior/Posterior of CHD and Anterior junction of CHD with 18%, 17% and 11% cases each, respectively. The Posterior junction of CHD recorded 6% cases. Whereas, Left side of CHD and the Anterior spiral recorded 3 cases, each. Only two cases of Posterior spiral were recorded in our study.

Discussion

During the 4^th week of foetal development, extrahepatic biliary organ arises along with the liver from the hepatic diverticulum of the foregut. In septum transversum, this diverticulum quickly proliferates and splits into 2 elements, respectively pars cystica and pars hepatica. Gallbladder and cystic duct arise from pars hepatica, liver and hepatic ducts and pars cystica. ^[7] Several scholars have reported that cells proliferate to form typical bile duct at junction of cystic and hepatic duct throughout the formation of pars cystica. ^[8,9] Failure of this usual pattern of growth contributes to numerous abnormalities. Awareness of anatomical differences in the hepato-biliary arrangement is critical through surgical and endoscopic processes, as a misreading of normal anatomy and anatomical differences leads to the prevalence of main postoperative problems such as biliary injuries. This can happen after cholecystectomy, with laparoscopic cholecystectomy having a higher occurrence. The cystic duct connects the gallbladder to the bile duct and is one of the main structures that during a typical cholecystectomy need careful diagnosis and separation. ^[10]

In this study, accessory ducts rising from the left lobe of the liver were not reported. Owing to late separation of hepatic antrum into cystic and hepatic diverticula, accessory hepatic duct develops, ^[11] otherwise the presence of a foetal link between liver and gallbladder. ^[12] Among Indian samples, Sharmila et al analysed the occurrence of 15 percent in 40 specimens in the South Indian populace. ^[13] Paul et al disclosed 26.7 percent of 30 specimens in the North Indian population. ^[14] In contrast, Devi et al. found that 17% of subjects had accessory hepatic ducts, while Khayat et al. reported just 3.33% of subjects. ^[15,16] Understanding the frequency and location of the accessory hepatic ducts is especially relevant throughout laparoscopic cholecystectomies as the occurrence of bile duct injury is double high as opposed to open cholecystectomies. ^[17]

Conclusion

The anatomy of the extra-hepatic biliary device is extremely complex and through surgical operations, such as laparoscopic cholecystectomy, liver resection and living organ relocation, any of these differences and abnormalities may be challenging for surgeons. Surgery done in the absence of abnormalities may lead to serious difficulties, such as duct leakage or liver atrophy. It is therefore important to provide a detailed understanding of the effective diagnosis and identification of such anatomical differences, thus lowering morbidity and mortality rates in hepatobiliary surgery.