Whipple surgery is the standard curative surgery for periampullary malignancy globally [12]. Despite the technical advancements, pancreaticoduodenectomy (Whipple surgery) remains a complex operation with significant morbidity and mortality rates even at experienced centers [13]. To make matters even more difficult, vascular anatomy is hindered by a great deal of variation. Michels [6] classified these hepatic arterial anomalies into 10 types and a modified classification was given by Hiatt et al. [9]. In the literature, there is some ambiguity on when to use the terminology 'aberrant’, ‘replaced’, and 'accessory’. In 11–21% of patients, the right hepatic artery (RHA) can be replaced (taking a path other than the normal course) [3, 14]. Most common anomaly is Michel's Type III i.e., arising from SMA [3, 14]. In 5% of cases, an accessory RHA (a blood supply other than the main artery) arises from the superior mesenteric artery, celiac trunk, or aorta [3, 14]. Both forementioned situations are classified as atypical RHA anatomy, which is referred to as aberrant RHA anatomy. The following are the most typically described anatomical variants of the hepatic artery: (1) an anomalous RHA from the SMA (10–21%); (2) replaced left hepatic artery (LHA) from the LGA (4–10%); (3) replaced RHA and LHA; (4) an accessory RHA and/or LHA (18%); (5) replaced CHA from the SMA or aorta (0.4–4.5%); or (6) quadrifurcation of hepatic artery [15]. Intricate embryological development is to blame for this abnormal vascular structure.
We here report a rare case of combination of RRHA originating from SMA passing anterior to head of pancreas and RLHA from LGA. RRHA after originating from SMA passes anterior to pancreas head and then anterior to CBD (Figs. 7 and 8). This course of anterior passage of RRHA is very rare. There are numerous anatomical variants (1.4–3%) that cannot be described using Michels and Hiatt’s classifications [16]. Using CT scan and digital subtraction angiography, Song et al. [3] presented the biggest dataset of celiac and hepatic artery variations in 5002 individuals. They described suprapancreatic, infrapancreatic, trans-pancreatic, pre superior mesenteric vein, and retro superior mesenteric vein, courses of CHA/RRHA [3]. Jah et al. [10], after observing 135 patients, proposed three different anatomical courses of RRHA in relation to the pancreatic head. Type 1 has a posterior route with respect to pancreatic head, Type 2 has intraparenchymal course and type 3 have a deeper route in the superior mesenteric vein (SMV) groove [10]. However, none of the anomalies described followed the same prepancreatic path as described in our case. The importance of this artery stems from the possibility of mistaking it for GDA, which comes from CHA, and ligating it while doing dissection, resulting in a reduction in blood flow to the liver and biliary tract. At this juncture, a clamp test would at the very least alert us to a problem. Furthermore, because this artery starts from the SMA near the pancreas neck and travels anteriorly, it might be damaged during neck transection or uncinate dissection. As a result, this case was set up for SMA first, with careful dissection of the artery from the pancreatic head using scissor and bipolar cautery. A non-artery first approach might have cause difficulty in recognizing the proper course of vessel and result in vascular damage at various points during the surgery, which would go unnoticed intra-operatively. Because hepatic artery primarily supplies the biliary system, maintaining arterial circulation to the liver during pancreaticoduodenectomy is critical. Damage to these can lead to bile leaks or biliomas, which can cause significant morbidity in the post-operative period. If arterial variations were discovered during the procedure, rather than prior to it, it could impact the outcome of pancreaticoduodenectomy and raise the rate of surgical complications such as pancreatic fistula, haemorrhage, hepatic ischemia or failure, and bile leakage [17]. It is possible to avoid morbidity and mortality by being aware of arterial aberrance and modifying surgical strategies accordingly.
Angiography can provide important details about aberrant vessels, but it does not provide details about relationship between the paths of the arteries and the pancreatic parenchyma, which is important information during presurgical planning. Hence contrast enhanced computed tomography with angiography becomes necessary in preoperative planning [11]. In major hepatobiliary and pancreatic surgery, various strategies have been described to manage an aberrant RHA: (1) resection versus preservation/reconstruction depending on whether the aberrant RHA is accessory or replaced, as well as depending on course of the artery in relation to pancreatic head and depending on whether the tumor infiltrates the vessel; (2) preoperative embolization; (3) temporary clamping and confirmation collateral circulation before ligation if discovered intraoperatively; and (4) neoadjuvant chemotherapy and reassessment [15, 18, 19]. In situations of early detection and proper therapy, an aberrant RHA appears to have no significant influence on the postoperative course and oncological results following PD [19, 20]. To minimize needless problems during and after PD surgery, a multidetector CT scan with reconstruction forms important part of preoperative evaluation and any aberrant vessels and there course should be noted and surgery planning should be done accordingly. Following that, the surgical strategy and intraoperative procedure are determined by the found vascular anatomical differences. If hepatic artery abnormalities are discovered during surgery, intraoperative treatment options include-ligation, dissection, and traction away from the dissection site, division, and anastomosis [15].
