Optimal Dissection of the Intestinal Tract and Preservation of Vascular Supply in Left Hemicolectomy Using Simulation Computed Tomography Colonography

: Left hemicolectomy is a standard surgical method for cancer of the descending colon. Resection involves the region from the left side of the transverse colon to the sigmoid colon. Although laparoscopic hemicolectomy is widely used, it is difficult to determine an appropriate resection range during surgery because of the limited visual field. Simulation computed tomography colonography(S-CTC), which combines CTC and 3-dimensional vascular imaging, enables the surgeon to clearly identify the position of the primary lesion and dominant vessel. We present 3 cases of cancer of the descending colon with different affected sites and lesion grades, in which appropriate dissection of the large intestine and treatment of the vessels was simulated by S-CTC, enabling laparoscopic surgery in accordance with the simulation. Case 1: Splenic flexure, cT1bN0M0, Stage I . The dominant vessels were identified by S-CTC as accompanying vessels branching from the accessary middle colic artery(A-MCA)and inferior mesenteric vein(IMV). The left branch of the MCA and the left colic artery(LCA)were 10 cm or more apart. A D2-type dissection was performed, and simulation was conducted for dissection of the branching root of the vein and the same level of the A-MCA. Case 2: Mid-descending colon, cT3N0M0, Stage II . The dominant A-MCA and LCA were identified with S-CTC. The intestinal tract was dissected to 5 cm from the dominant artery, and D3-type dissection was simulated with a retained inferior mesenteric artery(IMA)for preservation of the sigmoid colon. Case 3: Site adjacent to the sigmoid colon, cT3N0M0, Stage II . S-CTC identified the first sigmoid artery(S1)as the dominant artery, and revealed that the LCA and IMV were defective and that the A-MCA was 10 cm or more apart. Simulation of S1 selective resection was conducted such that D3-type dissection was performed, with a retained IMA for preservation of the sigmoid colon. In all 3 cases, laparoscopic surgeries were performed in accordance with the simulation. S-CTC was useful for optimal preservation of the intestinal tract and vascular supply in laparoscopic surgery for descending colon cancer.