Pattern of Tripus Halleri (trifurcation) of the coeliac trunk was first described by Haller in 1756. Normally, the celiac artery branches into the left gastric artery, the common hepatic artery, and the splenic artery [1]. Classical trifurcation of the celiac artery has been reported in 87.6% of the cadavers, and 12.4% had variable patterns [3]. Agenesis of the celiac trunk is a rare vascular anomaly with a mean prevalence of 0.38% [6]. The first case of the absent celiac artery was reported in 1832 by Geoffory Saint-Hilaire [3]. Aortic origination of all branches of the celiac axis is seen in 2% of cases [7]. In a systematic review of anatomical variation of celiac artery, 5 cases (41.7%) of the absent celiac trunk were identified out of total of 12 studies [2]. Nearly, 33% of these cases are diagnosed on radiological imaging [1]. 0.19% of 10750 CT scans had absent celiac trunk [4].
Various theories have been explained regarding the missing celiac trunk. It is believed that formative changes of ventral splanchnic arteries that have originated from paired ventral segmental arteries are responsible for morphological types of the celiac axis. The celiac trunk develops from the union of longitudinal anastomoses of segmental arteries. The absence of these anastomoses leads to the remnant of the segmental arteries and subsequent agenesis of the celiac trunk [4].
Initially, anatomical variants of the celiac trunk were classified by Lipshutz (1917) and Adachi (1928). Lipshutz described four variations of the celiac trunk: type I: coeliac artery branches into gastric, splenic, and hepatic arteries; type II: hepatic and splenic arteries arise from the coeliac axis and the gastric artery originates from the abdominal aorta; type III: the gastric and hepatic arteries arise from the coeliac axis whereas, the splenic artery separately branch from the abdominal aorta; and type IV: the gastric and the splenic arteries branch from the celiac artery and the hepatic artery comes from the abdominal aorta [5]. Adachi classified six types: (i) hepatogastrosplenic, (ii) hepatosplenic, (iii) gastrosplenic, (iv) coeliacomesenteric, (v) hepatosplenomesenteric, and (vi) hepatomesenteric [5].
Agenesis of the celiac trunk was not described in either of these classification systems of the celiac trunk. Morita proposed a modified version of the celiac axis classification which included absent celiac artery as one of the anatomical variants. Morita’s classification included (i) celiac trunk, (ii) hepatosplenic, (iii) gastrosplenic, (iv) hepatogastric, and (v) absent celiac trunk [1, 4].
According to Morita’s classification (1935), the presented case belongs to type V (Typus primitivus). Pre-operative knowledge of abdominal vascular anatomy in this case helped in careful identification and dissection of the left hepatic hilar structures during left donor hepatectomy. That included the left hepatic artery, the separate segment IV hepatic artery, the left hepatic duct, and the left portal vein. Following a careful dissection of these structures and the parenchymal dissection, ligation of the left hepatic artery and segment IV hepatic artery (arising from the right hepatic artery) were key steps in this case of donor hepatectomy. Failure to identify the common hepatic artery can lead to devastating effects on the vascularity of the remaining liver parenchyma in a live donor. The rest of the surgery was carried out without any special intervention or maneuver, with regards to vascular morphology.
This case highlights the importance of pre-transplant imaging as vascular variations when encountered intra-operatively can be challenging for the surgeon; also, CT imaging aids in preventing inaccurate resection and hence reducing donor-related morbidity and mortality.