A 48-year-old man from Mumbai undergoes laparoscopic cholecystectomy for symptomatic cholelithiasis. Intraoperatively, the surgeon identifies a small artery crossing the neck of the gallbladder before entering the cystic fossa. This vessel is not the cystic artery proper. The surgeon ligates what he believes to be the cystic artery, but postoperatively the patient develops bile leak from the gallbladder bed. Imaging confirms an intact cystic duct and artery. Which anatomical variant was most likely encountered?

Explanation

## Aberrant Hepatic Artery in Calot Triangle **Key Point:** An aberrant right hepatic artery crossing the Calot triangle is a critical anatomical variant present in 15–25% of the population. This vessel: - Arises from the proper hepatic artery or its branches - Crosses the Calot triangle en route to the right lobe - Is mistaken for the cystic artery and ligated inadvertently - Causes acute hepatic ischemia and bile leak from devascularized gallbladder bed **High-Yield:** The **aberrant right hepatic artery** is the most common vascular variant in the Calot triangle and the leading cause of iatrogenic vascular injury during cholecystectomy. ### Hepatic Artery Variants and Their Clinical Significance | Variant | Prevalence | Course | Risk in Cholecystectomy | |---------|-----------|--------|------------------------| | **Aberrant RHA** | 15–25% | Crosses Calot triangle | **HIGHEST** — mistaken for cystic artery | | Replaced RHA from GDA | 5–10% | Posterior to CBD, outside triangle | Lower — usually identified medially | | Replaced RHA from SMA | 1–2% | Enters from right, outside triangle | Lower — lateral to field | | Accessory RHA | 5–8% | Runs parallel to normal RHA | Lower — recognized as duplicate | | Replaced LHA from LGA | 5–10% | Anterior to hepatic hilum | Lower — outside Calot triangle | **Mnemonic for replaced hepatic arteries:** **"GALS"** = Replaced arteries come from **G**astroduodenal, **A**orta, **L**eft gastric, or **S**uperior mesenteric artery. ### Why This Variant Caused Bile Leak 1. Ligation of the aberrant right hepatic artery caused acute ischemia of the right lobe 2. The gallbladder bed (supplied by the cystic artery) became ischemic and necrotic 3. Necrotic tissue leaked bile into the peritoneal cavity 4. The true cystic artery remained intact but the gallbladder was devascularized **Clinical Pearl:** The "critical view of safety" technique requires identification of: - Two structures crossing the hepatocystic triangle (cystic artery and cystic duct) - Clear view of the liver bed - Absence of a third crossing structure If a third vessel is seen, it is likely an aberrant hepatic artery and should NOT be ligated. **Warning:** Do not assume every artery in the Calot triangle is the cystic artery. Aberrant vessels are common and ligation causes serious morbidity. [cite:Standring Gray's Anatomy 42e; Sabiston Textbook of Surgery Ch 51]