Intraoperative Indocyanine Green Imaging for the Evaluation of Blood Perfusion Area in Cancer of the Splenic Flexure With an Occluded Inferior Mesenteric Artery: A Report of Two Cases

Radical resection for cancer of the splenic flexure requires careful consideration of the dissection line so that blood flow in the remnant bowel is maintained, particularly when the root of the inferior mesenteric artery (IMA) is already occluded. Intraoperative indocyanine green (ICG) imaging is a promising method for evaluating blood perfusion of organs and vessels. However, there are few reports on the use of ICG to determine the dissection line in patients with altered blood flow. In this article, we describe two cases of successful resection of splenic flexure cancer (SFC) in patients with an occluded IMA under ICG guidance. Case one was a 76-year-old man with a diagnosis of stage III SFC who had previously undergone endovascular aortic repair without reimplantation of the IMA. Intraoperative ICG imaging revealed that the left side of the colon was perfused mainly by the left branch of the middle colic artery (MCA). We performed a hemicolectomy with preservation of the MCA-left colic artery (LCA) arcade and resected an enlarged lymph node en bloc. Case two was a 77-year-old man with a diagnosis of stage II SFC in whom the root of the IMA appeared to be occluded by arteriosclerosis. Computed tomography showed that the LCA was anastomosed to the accessory middle colic artery (AMCA) while the left branch of the MCA was joined to the marginal artery. Intraoperative ICG imaging revealed that the left side of the colon was perfused by the AMCA and not the MCA. By preserving the AMCA-LCA arcade, we were able to safely divide the left branch of the MCA. Both patients were discharged with no symptoms of bowel ischemia or recurrence of cancer during follow-up. Interindividual variation in vessel branching patterns and dominant vessels in the descending and distal transverse colon may result from congenital factors or acquired disease. Detailed information on blood perfusion is required to avoid postoperative bowel ischemia. This report is the first to focus on patients with SFC and altered blood flow. We show that ICG imaging might be a reasonable option for determining an adequate surgical dissection area.