Cystic Duct Normal Anatomy and Anatomic Variants.pptx

Cystic Duct Normal Anatomy and Anatomic Variants.

1. Case Presentation A 43 y.o female patient PMH negative PSH negative Case of symptomatic cholelithiasis Labs totally normal

2. The Cystic Duct: Normal Anatomy and Anatomic Variants

3. Figure 1.   Drawing illustrates the normal biliary tract. The cystic duct (arrows) connects the gallbladder to the extrahepatic bile duct and usually enters from the right approximately halfway between the porta hepatis and the ampulla of Vater . It also contains the valves of Heister. Normal Anatomy The cystic duct attaches the gallbladder to the extrahepatic bile duct; its point of insertion into the extrahepatic bile duct marks the division between the common hepatic duct and the common bile duct.

4. Figure 2.   Normal cystic duct anatomy. ERCP image shows a normal-caliber cystic duct (solid arrow). Note the undulating contour of the duct produced by the valves of Heister . An air bubble (open arrow) is noted in the common bile duc t. Absence of filling of the cystic duct at ERCP is usually related to patient positioning rather than cystic duct obstruction.

5. Figure 5.   Coronal oblique MR cholangiopancreatogram demonstrates the normal cystic duct (arrow) connecting the gallbladder to the extrahepatic bile duct (arrowhead). Gallbladder calculi are also present.

6. Figure 6.   Anatomic variants in the cystic duct. Drawings illustrate how the cystic duct may insert into the extrahepatic bile duct with a shows right lateral insertion ( A ), anterior spiral insertion ( B ), posterior spiral insertion ( C ), low lateral insertion with a common sheath ( D ), proximal insertion ( E ), or low medial insertion ( F ). Anatomic Variants Variations in Cystic Duct Insertion

7. Figure 7a.    (7a) Cholangiogram shows a right lateral insertion of the cystic duct (arrows) into the extrahepatic bile duct. (7b) Cholangiogram shows a medial insertion of the cystic duct (arrows) into the extrahepatic bile duct. (7c) Coronal oblique MR cholangiopancrea-togram shows a low, medially inserting cystic duct (straight arrows) that parallels the bile duct (curved arrow).

8. Figure 9.   Low medial insertion of the cystic duct into the ampulla of Vater in an 11-year-old girl with recurrent pancreatitis. ERCP image shows direct filling of the cystic duct (single straight arrow) from an ampullary injection of contrast material. The cystic duct and bile duct (double arrows) join at the ampulla. Stones are identified in the cystic duct (curved arrow), and air is noted in the gallbladder ( g ). Recurrent pancreatitis in the patient was attributed to this abnormal anatomy.

9. Figure 10a.   Calculus in a low, medially inserting cystic duct mimicking a distal common bile duct calculus in a 69-year-old man. (a) ERCP image shows a low, medially inserting cystic duct remnant (straight arrows) mimicking the distal bile duct. The calculus (curved arrow) in the cystic duct remnant was initially presumed to lie in the distal bile duct. (b) ERCP image obtained after rotating the patient demonstrates a catheter in the cystic duct remnant (straight arrows) and shows that the calculus (curved arrow) lies in the cystic duct remnant. No calculus is seen in the distal bile duct (arrowheads).

10. Anatomic Variants Anomalous Bile Ducts

11. Figure 12a.   Aberrant junction of the bile duct and cystic duct. (a) ERCP image shows an aberrant right hepatic duct (small arrows) entering the cystic duct (large arrow) . (b) Coronal MR cholangiopancreatogram obtained in a different patient demonstrates an aberrant right hepatic duct (small arrows) draining a circumscribed portion of the liver and entering the common hepatic duct 4 cm distal to the confluence of the right and left hepatic ducts. The cystic duct (large arrow) drains into the aberrant right hepatic duct . (Figure 12 reprinted, with permission, from reference 20.)

12. Laparoscopic cholecystectomy (LC) is the most common elective laparoscopic procedure performed globally and is the gold standard treatment for gallstone disease. The bile duct injury (BDI) remains the most dreaded complication, with an incidence rate of 0.3 %. Clear identification of biliary anatomy and establishing the critical view of safety is essential in avoiding BDI . However, this can be challenging, with variations in biliary anatomy in ~47% of patients. An extremely rare variant is the duplicated cystic duct.

13. Case Presentation A 57-year-old woman was admitted to our hospital due to epigastric abdominal pain . A physical examination revealed no remarkable findings. Laboratory studies showed an elevated white blood cell count (10400/ μL ), aspartate aminotransferase (AST: 84 U/L), alanine aminotransferase (ALT: 39 U/L), alkaline phosphatase (ALP: 466 U/L), γ- glutamyl transpeptidase 205 U/L). Ultrasonography and computed tomography (CT) revealed small gallstones in the gallbladder and some stones in the common bile duct . A large liver cyst was also detected in S4. Thus, the patient was diagnosed with cholecysto-choledocholithiasis . Laparoscopic cholecystectomy was planned after the complete removal of the gallstones in the common bile duct following endoscopic sphincterotomy (EST). However, a cystic duct which communicates with the intrahepatic bile duct of the posterior segmental branch was suspected based on the gross X-ray images obtained after the extraction of the bile duct stones. Therefore, the magnetic resonance cholangiopancreatography (MRCP) was performed. MRCP showed strong suspicion of a single gallbladder with a double cystic duct.

14. Thus , to confirm this rare condition, endoscopic retrograde cholangiography (ERC) was additionally performed for a second time . This time, a normal cystic duct was found to arise from the neck of the gallbladder, from which it descended and joined the common bile duct. In addition, the aberrant cystic duct arose from the cystic duct and communicated with the intrahepatic bile duct of the posterior segmental branch. Thus , we determined that the patient had a single gallbladder with a double cystic duct . An endoscopic nasobiliary drainage (ENBD) tube was placed for intraoperative cholangiography in order to protect the common bile and hepatic duct from injury during surgery. Laparoscopic cholecystectomy was performed under general anesthesia. During the procedure, the gallbladder was divided from the gallbladder bed in the fundus- to- hilar direction , in order to explore the double bile ducts. The main and aberrant cystic ducts and the common hepatic duct were identified by meticulous dissection and intraoperative cholangiography. These cystic ducts were then ligated and precisely divided. Laparoscopic cholecystectomy was finished and no drain was placed . The excised specimen showed a duplicated cystic duct containing debris and chronic cholecystitis

15. With more than half a million cholecystectomies performed annually, variations in biliary anatomy present a significant challenge for laparoscopic surgeons. Duplication of the cystic duct is extremely rare, with only 20 previous cases reported in the literature. Three types of duplicated cystic ducts have been previously described: The ‘Y’ type, in which two cystic ducts meet to form a common channel . the ‘H’ type, in which the accessory duct enters into the right, left or common hepatic duct. the trabecular type, in which the accessory duct enters the liver substance directly . While preoperative MRCP or endoscopic retrograde cholangiopancreatography (ERCP) may identify abnormal anatomy, this is not guaranteed to prevent encountering unexpected variations.

16. Of the seven reported cases of cystic duct duplication where a preoperative ERCP was performed , only three had the anomaly detected. In most cases, the second cystic duct was an intraoperative finding . This emphasizes the importance of constant vigilance during LC even when preoperative imaging yields no abnormality . In conclusion , the duplicated cystic duct is a highly uncommon variant of biliary anatomy, which may pose a significant dilemma to the laparoscopic surgeon. Constant vigilance for anatomical variance is essential to avoid adverse outcomes, with early involvement of a hepatobiliary specialist if there is unexplained bile leakage . Unremarkable preoperative imaging does not exclude the presence of abnormal anatomy .

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