Posterolateral Common Bile Duct Configuration: Risk of Common Bile Duct Injury During Laparoscopic Cholecystectomy

Two patients presented with biliary colic symptoms and no clinical evidence of congenital anomalies suggestive of biliary tree variation. One patient underwent preoperative computed tomography (CT), which did not mention any anomaly, though on review of the imaging (Figure 1A) demonstrated a transverse orientation of the gallbladder with the common bile duct (CBD) situated posterolaterally to the gallbladder. Intraoperatively, both cases revealed strikingly similar anatomical findings. The gallbladder had a prominent Hartmann's pouch directed medially with a normally positioned cystic artery. Notably, the posterior gallbladder-liver interface was ill-defined. Further dissection revealed that this obscurity was due to the posterolateral course of the CBD, which lay intimately along the gallbladder's posterior aspect. The Rouvière's sulcus was absent, correlating with a deeply situated CBD bifurcation. The cystic duct was short (< 5 mm) and inserted directly onto the side of the CBD anteriorly (Figure 2A,B). A sharp right-angle turn of the CBD at the choledocho-cystic junction was observed, likely due to traction forces pulling the gallbladder superiorly away from the CBD, but the angulation was seen on the preoperative CT (Figure 1B). Both procedures proceeded uneventfully. One patient exhibited minimal contrast passage into the duodenum on intraoperative cholangiogram, necessitating postoperative endoscopic retrograde cholangiopancreatography for biliary sludge extraction. Both patients were asymptomatic at four-week follow-up. This posterolateral variant of the CBD presents a unique hazard during cholecystectomy and it does not conform to the current biliary anatomy classification [1]. Specifically, blind posterior dissection behind the gallbladder infundibulum using Maryland forceps risks direct injury to the CBD [2]. In both cases, the CBD extended posterolaterally beneath what was initially thought to be gallbladder-proper, incorporating more than half of the apparent posterior gallbladder wall, when compared to the anteromedial side. To mitigate the risk of CBD injury in such anatomical scenarios, the gallbladder should be mobilized from the anteromedial side toward the fundus and the cystic plate before addressing the posterolateral side. Cystic duct ligation should be the final step. Direct visualization of dissection planes is paramount, especially when posterior anatomy is unclear or distorted. Posterolateral positioning of the CBD is a rare but potentially dangerous anatomical variation. Surgeons should maintain a high index of suspicion when reviewing images or encountering atypical gallbladder orientation. Early recognition and modification of technique are key to preventing major bile duct injury. The author declares no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.