Behind the Knife ABSITE 2026: Hepatobiliary System Review

Hepatobiliary Anatomy and Aberrant Vessels

• 💡 The portal triad consists of the common bile duct (anterior lateral), proper hepatic artery (anterior medial), and portal vein (posterior).
• 📌 Canley's line, an imaginary line between the gallbladder fossa and the IVC, separates the right and left lobes of the liver.
• 🧠 The liver is drained by three hepatic veins that empty directly into the IVC; the medial and left hepatic veins often merge.
• ⚠️ Common aberrant vessels include the replaced right hepatic artery (can branch from SMA) and replaced left hepatic artery (can branch from left gastric artery), requiring caution during surgery.

Benign Biliary Disease Management

• 🎯 Asymptomatic gallstones are managed with observation.
• ✅ Symptomatic cholelithiasis typically requires elective laparoscopic cholecystectomy.
• 🤰 For symptomatic cholelithiasis in pregnancy, laparoscopic cholecystectomy is considered safe in any trimester, with second trimester often preferred.
• 🏥 Acute cholecystitis is managed with early cholecystectomy; a cholecystostomy tube is an option for non-surgical candidates, followed by definitive cholecystectomy later.
• 🌟 Prophylactic cholecystectomy is recommended for patients with sickle cell anemia, porcelain gallbladders, large gallstones (>2.5 cm), large polyps (>1 cm), or known gallstones undergoing bariatric surgery.

Choledocholithiasis and Gallstone Pancreatitis

• 🔍 Suspicion for choledocholithiasis arises from abnormal LFTs, elevated bilirubin, dilated common bile duct (>6 mm), or clinical cholangitis.
• 🩺 Management options include pre-operative ERCP, intraoperative cholangiogram (IOC) with possible common bile duct exploration, or post-operative ERCP.
• 🚨 Patients with clinical cholangitis require emergent biliary drainage, preferably via ERCP, not immediate surgery.
• 💡 If IOC reveals common bile duct stones, initial steps include flushing the duct, followed by trans-cystic or direct common bile duct exploration, or post-operative ERCP.
• ⚠️ Gallstone pancreatitis requires ERCP if there are clinical signs of cholangitis or a persistent common bile duct stone.
• ⏳ For severe gallstone pancreatitis with pancreatic fluid collections, wait for collections to mature before intervention; ERCP and sphincterotomy can reduce recurrence risk.

Gallstone Ileus and Mirizzi Syndrome

• 🕳️ Gallstone ileus is a small bowel obstruction caused by a gallstone, typically at the ileocecal valve, due to a cholecystoenteric fistula.
• 🩺 The classic triad includes bowel obstruction, a gallstone in the intestine, and pneumobilia.
• 🛠️ Treatment involves enterotomy proximal to the obstruction, milking the stone back, and removing it; the gallbladder is usually left in place.
• ⚠️ Mirizzi syndrome involves external compression of the common hepatic duct by a stone in the cystic duct; management is typically cholecystectomy, sometimes subtotal.

Gallbladder Polyps and Biliary Strictures

• 📈 Gallbladder polyps are usually hyperplastic; management depends on size and symptoms, with resection recommended for symptomatic polyps, asymptomatic polyps >10 mm, or those >18 mm (treated as cancer).
• ⚠️ Biliary strictures post-cholecystectomy can be iatrogenic (transection, clip, thermal injury) and may require endoscopic dilation or surgical intervention.
• 🧩 Sphincter of Oddi dysfunction is managed with endoscopic sphincterotomy.

Portal Hypertension and Its Management

• 📊 The hepatic vein pressure gradient (HVPG), normally <6 mmHg, is >6 mmHg in portal hypertension.
• 📉 Clinical signs include varices, ascites, hepatic encephalopathy, and hepatosplenomegaly.
• 🌍 Causes of increased portal resistance include presinusoidal (schistosomiasis), sinusoidal (cirrhosis), and postsinusoidal (Budd-Chiari syndrome).
• 🔗 Collateral circulation occurs at the gastroesophageal junction, rectum, umbilicus, and retroperitoneum.
• 💊 Pharmacologic management includes splanchnic vasoconstrictors (vasopressin, octreotide) and non-selective beta-blockers (propranolol).
• 🚀 TIPS (Transjugular Intrahepatic Portosystemic Shunt) decompresses the portal system for bleeding, refractory ascites, or Budd-Chiari syndrome, but can worsen hepatic encephalopathy.
• 🩸 Acute variceal bleeding requires resuscitation, antibiotics, endoscopy, balloon tamponade, octreotide, and potentially emergent TIPS.
• 🔀 Portosystemic shunts include selective (splenorenal), partial non-selective (PTFE graft), and non-selective (portocaval) shunts.

Liver Abscesses and Cystic Lesions

• 🦠 Pyogenic abscesses are the most common, usually secondary to biliary or GI infections (E. coli is common); managed with percutaneous drainage and antibiotics.
• ✈️ Amebic abscesses are treated with metronidazole and rarely require drainage.
• 🪞 Hydatid cysts are managed with albendazole followed by PAIR technique (puncture, aspiration, injection, reaspiration) or surgical resection.
• 🧬 Choledochal cysts (Todani classification) involve dilation of the biliary tree; management ranges from resection with hepaticojejunostomy (Type I) to excision (Type II), sphincteroplasty (Type III), resection/reconstruction (Type IV), or liver transplant (Type V).
• 💧 Simple hepatic cysts are observed if asymptomatic; symptomatic ones may undergo laparoscopic fenestration.

Hepatobiliary Tumors

• 🌟 Hepatic hemangiomas are the most common liver tumors, typically asymptomatic; symptomatic lesions are resected.
• 🌸 Focal nodular hyperplasia (FNH) is the second most common, characterized by a central stellate scar; observation is usual.
• 💊 Hepatic adenomas are associated with OCP use, have malignant potential, and risk of rupture; small lesions may regress after stopping OCPs, larger ones are resected.
• 📈 Hepatocellular carcinoma (HCC) risk factors include viral hepatitis, cirrhosis, and aflatoxins; diagnosis is often made on imaging with elevated AFP, and resection is preferred for solitary masses with adequate liver function.
• 🏥 For HCC not amenable to resection, liver transplantation (Milan criteria) or locoregional therapies (TACE, ablation, radiation) are options.
• 🎗️ Cholangiocarcinoma can be intrahepatic or extrahepatic; management involves complete resection with negative margins, often with biliary reconstruction (e.g., Roux-en-Y hepaticojejunostomy) or Whipple procedure for distal disease.
• ⚠️ Gallbladder cancer risk factors include obesity, large gallstones, and chronic inflammation; diagnosis is often incidental, with T1A treated by cholecystectomy alone, and T1B or greater requiring liver resection (segments 4B/5) and lymphadenectomy.

Quick Hits and Segmental Resections

• 🌡️ Variceal rupture risk increases with HVPG around 12 mmHg.
• ⚖️ Portal hypertension is defined as HVPG ≥ 6 mmHg.
• 📊 Child-Pugh score components: bilirubin, albumin, PT, encephalopathy, ascites.
• 🔢 MELD score components: bilirubin, INR, creatinine, sodium.
• 🏆 Transplant benefit for MELD ≥ 15.
• 🔬 Isolated liver mets from colorectal cancer are resected even after neoadjuvant therapy.
• 🫘 Asymptomatic cholelithiasis with a 5mm polyp warrants cholecystectomy due to potential malignancy risk.
• 🧪 Normal GGT has high negative predictive value for choledocholithiasis.
• 🔄 Post-gastric bypass patients with choledocholithiasis may require transgastric ERCP.
• 🧬 Fibrolamellar HCC in young patients without cirrhosis has a better prognosis and is marked by neurotensin.
• 🫙 Incidental T1A gallbladder adenocarcinoma requires only cholecystectomy; T1B requires liver resection (segments 4B/5) and lymphadenectomy.
• 🗺️ Liver resections involve specific segments: Right (5-8), Left (2-4 ± caudate), Left Lateral (2-3), Extended Right (5-8 + 4), Extended Left (2-4 + 5, 8).