[D2 Lymph Node Dissection in Mini-Laparotomy Transverse Colectomy Using Non-Contrast Simulation CT Colonography]

It is reported that simulation computed tomography colonography(S-CTC), which combines CTC and 3-dimensional(3D)vascular imaging, is useful in colorectal cancer surgery. However, it is difficult to create 3D vascular images using non-contrast CT. Laparoscopic transverse colectomy is said to be technically difficult. Mini-laparotomy surgery for mid-transverse colon cancer is quite easy to perform. However, exact D2 lymph node dissection is very difficult. We present a case of D2 lymph node dissection during mini-laparotomy transverse colectomy performed using S-CTC, which involves the creation of 3D vascular images using non-contrast CT.The patient was a 77-year-old man with transverse colon cancer located in the mid-transverse colon, cT2N0M0, Stage Ⅰ. He had coexisting chronic renal failure. Non-contrast CT was performed prior to surgery, and the images were processed using workstation Zaiostation2.Both the artery and the vein created from non-contrast CT could be visualized clearly until the marginal vessels. Using noncontrast S-CTC in combination with CTC and 3D artery imaging, it was identified that the dominant artery was the left branch of the middle colic artery(MCA Lt), while the right branch of the MCA(MCA Rt)and accessory MCA(AMCA)were 10 cm or more apart. The fusion of 3D artery and vein imaging made it evident that the vein accompanying MCA Lt branched from the superior mesenteric vein. Using non-contrast S-CTC, D2 lymph node dissection, dissection of the branching root of MCA Lt and the vein at the same level was simulated. Thus, mini-laparotomy transverse colectomy was performed through a 7 cm incision, in accordance with the simulation.Non-contrast S-CTC was useful for performing D2 lymph node dissection during mini-laparotomy transverse colectomy.