Aberrant splenic artery rising from the superior mesenteric artery: a rare but important anatomical variation

Classification of the Superior Mesenteric Artery

The aim of this study was to characterize the branching pattern and morphology of the superior mesenteric artery (SMA), and also to create a new SMA classification, which seems necessary for clinicians performing surgery in this anatomical area. The anatomical variations in the branching patterns of the SMA were examined in 30 cadavers fixed in 10% formalin. Morphometric measurements were then obtained twice by two researchers. In the proposed classification system, Type I, characterized by all normal branches - inferior pancreatoduodenal artery, ileocolic artery, right colic artery, middle colic artery and intestinal arteries - occurred in 53.33% of the specimens. Type II, characterized by absence of the inferior pancreatoduodenal artery, was present in 26.67%. Type III, characterized by absence of the right colic artery, was present in 3.33%. Type IV, characterized by a common trunk for the inferior pancreatoduodenal artery and middle colic arteries, was observed in 3.33%. Type V, characterized by an aberrant hepatic artery and absence of the inferior pancreatoduodenal artery, was observed in 13.33%. The origin of the SMA was at the Th12/L1 level in 10% of cases, at L1 in 43.33%, at L1/L2 in 36.67%, and at L2 in 10%. The SMA is characterized by high morphological variability, the variants being associated with distinct clinical aspects. The introduction of a new, structured, anatomical classification seems necessary for all clinicians.

Laparoscopic distal pancreatectomy in a patient with aberrant splenic artery originating from the superior mesenteric artery: A case report

RATIONALE

Splenic artery originating from the superior mesenteric artery is extremely rare. Because of this, its significance in laparoscopic distal pancreatectomy has never been reported. Here, we present the first case of laparoscopic distal pancreatectomy in a patient with a splenic artery arising from the superior mesenteric artery.

PATIENT CONCERNS

A 46-year-old Japanese woman with type 2 diabetes mellitus presented with worsening glycemic control. Abdominal ultrasonography revealed a pancreatic tail mass.

DIAGNOSES

The patient was diagnosed with pancreatic neuroendocrine tumor by endoscopic ultrasound-guided fine needle aspiration. Preoperative computed tomography showed that the splenic artery with branches of dorsal pancreatic artery originated from the superior mesenteric artery.

INTERVENTIONS

The patient underwent laparoscopic distal pancreatectomy. Prior to pancreatectomy, the splenic artery and its dorsal pancreatic branches were clamped using the superior and inferior approaches, respectively, to avoid bleeding and congestion.

OUTCOMES

The postoperative course was uneventful.

LESSONS

Preoperative evaluation of anatomical variants and development of strategies are important to avoid intraoperative complications in pancreatic surgery. Our results revealed that laparoscopic distal pancreatectomy can be performed safely by strategic approach even in a patient with a rare aberrant splenic artery.