An Aberrant Common Hepatic Artery Originating From the Superior Mesenteric Artery With a Retroportal Course: A Rare Anatomical Variant of Surgical Importance

During preoperative assessment for laparoscopic pancreaticoduodenectomy, contrast-enhanced CT and three-dimensional angiography revealed an aberrant vascular anatomy: the common hepatic artery (CHA) originated from the superior mesenteric artery (SMA). After its origin, the artery ascended along the right margin of the SMA, passed posterior to the superior mesenteric vein (SMV), and then coursed behind the portal vein (PV). At the point where it gave rise to the gastroduodenal artery (GDA), the CHA curved anterosuperiorly from its retroportal position and continued as the hepatic artery proper toward the hepatic hilum (Figure 1). Intraoperative findings confirmed the retroportal course of the CHA, which was identified during dissection of the hepatoduodenal ligament and isolation of the GDA. The aberrant course necessitated special attention to avoid vascular injury during GDA division (Figure 2). According to Hiatt's classification, this corresponds to a type IX variant, in which the CHA arises from the SMA rather than the celiac trunk [1]. The prevalence of a replaced CHA arising from the SMA is approximately 2% in large anatomical and radiologic series, a rate that, although uncommon, holds clear surgical significance [1-6]. Replaced CHAs arising from the SMA have been reported with variable courses, including anterolateral, retroportal, and transpancreatic trajectories [7]. The retroportal course, as demonstrated in our case, carries particular risk during pancreaticoduodenectomy because of its close relationship to the PV and SMV, and is especially vulnerable during the isolation and division of the GDA. Unrecognized injury can lead not only to hepatic ischemia but also to compromised arterial inflow to the biliary tree, predisposing to anastomotic leakage or stricture [8]. In addition, the anomalous origin from the SMA may complicate vascular control in cases requiring arterial reconstruction, and comparable variants have been shown to influence outcomes in liver transplantation, interventional radiology, and hepatic arterial infusion chemotherapy [9]. In our case, the anatomy was clearly delineated by high-quality three-dimensional angiography and confirmed intraoperatively, underscoring the necessity of accurate preoperative vascular mapping. Three-dimensional CT angiography provides a reliable tool to delineate vascular anatomy beyond conventional axial imaging. While experienced surgeons can often infer vascular variations from standard CT, 3D reconstruction offers a more accurate and intuitive roadmap, improving intraoperative safety. We recommend routine preoperative 3D vascular mapping prior to pancreaticoduodenectomy to identify aberrant vessels such as a retroportal CHA. This approach enhances surgical planning, facilitates safe arterial dissection, and reduces the risk of life-threatening vascular complications. Written informed consent was obtained from the patient. The authors declare no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.