Shuji Saito, MD, Hitomi Takaishi, MD, Ryo Otsuka, MD, Ryoichi Hirayama, MD. Yokohama Shin-Midori General Hospital
INTRODUCTION: The arterial divergence form and distribution flowing into the transverse colon are highly individualized. Under the Japanese D3 lymph node dissection method for transverse colon cancer, we dissect along and preserve the common trunk of the middle colic artery (MCA) and ligate and divide a root of the right branch or the left branch; however, the length of the common trunk of the MCA varies on an individual basis. We occasionally encounter an anomalous artery associated with the transverse colon. One of them is the so-called accessory left colic artery (A-LCA), which originates from the superior mesenteric artery (SMA), runs between the MCA left branch and left colic artery, and supplies the splenic flexure. The frequency of the A-LCA is not described in anatomical scholarly books. It may be difficult to confirm arterial divergence laparoscopically during an operation, which can prolong the operative time. The aim of this study was to examine the arterial divergence form flowing into the transverse colon using preoperative 3D-CT angiography (3D-CTA).
METHODS AND PROCEDURES: We confirmed the arterial run flowing into the transverse colon using preoperative 3D-CTA for 52 colon cancer cases. We confirmed the divergence form of the right branch and left branch of the MCA and measured the length of the common trunk. We defined arteries which diverged from the SMA near or on the proximal side of the first jejunal artery or the celiac artery (CA) and flowed into the colon of the spleen flexure to be A-LCA. We additionally confirmed the presence or absence of the A-LCA using preoperative 3D-CTA for 108 colon cancer cases.
RESULTS: Fifty-two MCAs were observed in all cases; in nine patients (17%) there was independent divergence of the right branch and left branch without forming a common trunk. In 43 patients that formed a common trunk, the mean length of the common trunk was 3.1 ± 1.9 (0.8-9.7) cm. We recognized A-LCA in 39% (42/108) of all cases, and four A-LCAs diverged from the CA.
CONCLUSION: Confirming the course of the feeding artery preoperatively using 3D-CTA is an essential preoperative examination for laparoscopic surgery in order to perform precise, minute dissection of the transverse colon cancer.