Evaluation of the vascular anatomy of the left-sided colon focused on the accessory middle colic artery: a single-centre study of 734 patients.

Abstract

Surgery for colorectal cancer located in the splenic flexure is difficult to perform because of the complex anatomy. Recently, in addition to the middle colic artery and left colic artery (LCA), the accessory middle colic artery (AMCA) has been recognized as a feeding artery for the left-sided colon. This study aimed to evaluate the vascular anatomy of the splenic flexure focusing on the AMCA in a large number of patients. A total of 734 patients who underwent CT before surgery for colorectal cancer were enrolled. We retrospectively evaluated the vascular anatomy using both two- and three-dimensional CT angiography. The AMCA existed in 36.4% of the cases (n = 267). In many cases, it originated from the superior mesenteric artery (n = 228, 85.4%). The AMCA had a common trunk with the transverse pancreatic artery in 54 patients (20.2%). The frequency of the presence of the AMCA was associated with the branching pattern of the LCA, and was more frequent when the LCA was absent (P < 0.001). The presence of the AMCA is not rare and the AMCA has some branching patterns; therefore, recognizing it preoperatively and intra-operatively is important, being especially careful when the LCA is absent.