1. PTC - Percutaneous Transhepatic Cholangiography

• Obstructive jaundice when ERCP is unsuccessful/not possible.
• To define the level and cause of biliary obstruction, especially hilar obstruction.
• For percutaneous biliary drainage or stenting.

• Haemorrhage/haemobilia, bile leak and biliary peritonitis.
• Cholangitis/sepsis.
• Pneumothorax or pleural effusion if a high intercostal approach is used.

2. ERCP - Endoscopic Retrograde Cholangiopancreatography

• Therapeutic: CBD stone extraction, endoscopic sphincterotomy, biliary stenting for benign/malignant stricture, drainage in cholangitis and treatment of bile leak.
• Diagnostic: Defines site/cause of biliary or pancreatic duct obstruction. Diagnostic ERCP is now largely replaced by MRCP/EUS.

• Acute pancreatitis - most common.
• Cholangitis, bleeding after sphincterotomy, perforation.
• Sedation-related complications.

3. HIDA Scan - Hepatobiliary Iminodiacetic Acid Scan

• Suspected acute cholecystitis: non-visualisation of gallbladder due to cystic duct obstruction.
• Detection of bile leak after trauma or biliary surgery.
• Assessment of biliary obstruction, biliary atresia and gallbladder function.

• Normal: liver uptake, biliary excretion, gallbladder and intestinal activity are seen.
• Acute cholecystitis: gallbladder is not visualised despite tracer in CBD/small bowel.

4. OCG - Oral Cholecystography

• Demonstrates gallbladder size, concentration and contractility.
• Gallstones appear as radiolucent filling defects.
• Non-visualisation may occur in cystic duct obstruction, acute cholecystitis or non-functioning gallbladder.

• Not useful in jaundice, vomiting, malabsorption or poor hepatic function.
• It is now largely obsolete and has been replaced by ultrasonography, MRCP and HIDA scan.

5. Common Bile Duct Exploration - Indications

1. Documented CBD stones on imaging, ERCP or intraoperative cholangiography.
2. Failed, incomplete or unavailable ERCP, or stones not amenable to endoscopic extraction.
3. Multiple, large, impacted or recurrent CBD stones.
4. Persistent obstructive jaundice/cholangitis due to choledocholithiasis when operative clearance is required.
5. Stones detected during cholecystectomy where single-stage laparoscopic clearance is feasible.

6. Anatomical Variations of CBD and Extrahepatic Biliary Tree

1. Variation in cystic duct insertion
   • High or low insertion into common hepatic duct.
   • Parallel course of cystic duct alongside common hepatic duct.
   • Spiral insertion from anterior or posterior aspect.
   • Short cystic duct or rarely absent cystic duct.
2. Aberrant hepatic ducts
   • Right posterior sectoral duct may drain into the common hepatic duct, cystic duct or gallbladder.
   • Accessory hepatic ducts may open into cystic duct or common hepatic duct.
3. Variation in formation/course of CBD
   • Unusual union of cystic duct with common hepatic duct.
   • Rare duplication of CBD.
   • CBD may have an abnormal course in relation to portal vein or hepatic artery.
4. Anomalous pancreaticobiliary junction
   • Union of CBD and pancreatic duct outside the duodenal wall, forming a long common channel.
   • Associated with reflux of pancreatic juice and choledochal cysts.

Anatomical variations of the common bile duct and extrahepatic biliary tree

Normal anatomy

Variations

1. Variations in cystic duct
   • Low insertion into the CHD, close to the duodenum.
   • High insertion near hepatic duct confluence.
   • Cystic duct may run parallel to the CHD for a variable distance before joining it.
   • Spiral insertion from the anterior, posterior, medial or left side of CHD.
   • Short, long, absent, duplicated or accessory cystic duct may occur.
2. Aberrant/accessory hepatic ducts
   • An accessory right hepatic duct may drain into the CHD, cystic duct or gallbladder.
   • The right posterior sectoral duct may drain directly into CHD, left hepatic duct, cystic duct or gallbladder neck.
   • A subvesical duct, often called a duct of Luschka, may be present in the gallbladder fossa and can cause postoperative bile leak.
3. Variations in CBD formation and course
   • Unusual level or angle of union of cystic duct with CHD.
   • Rarely, the CBD may be duplicated or septate.
   • The CBD may have an abnormal relation to the portal vein or hepatic artery, for example a right hepatic artery passing anterior to the CHD/CBD.
4. Anomalous pancreaticobiliary junction
   • CBD and pancreatic duct unite outside the duodenal wall, producing a long common channel.
   • This permits reflux of pancreatic juice into the bile duct and is associated with choledochal cyst and increased biliary malignancy risk.

Surgical importance