Safety and effectiveness of high ligation of the inferior mesenteric artery for cancer of the descending colon under indocyanine green fluorescence imaging: a pilot study

Background Complete mesocolic excision with central vascular ligation is a standard advanced technique for achieving favorable long-term oncological outcomes in colon cancer surgery. Clinical evidence abounds demonstrating the safety of high ligation of the inferior mesenteric artery (IMA) for sigmoid colon cancer but is scarce for descending colon cancer. A major concern is the blood supply to the remnant distal sigmoid colon, especially for cases with a long sigmoid colon. We sought to clarify the safety and feasibility of high ligation of the IMA in surgery for descending colon cancer using indocyanine green (ICG) fluorescence imaging. Methods In this prospective single-center pilot study, we examined 20 patients with descending colon cancer who underwent laparoscopic colectomy between April 2018 and September 2019. Following full mobilization and division of the proximal colonic mesentery, we temporarily clamped the root of the IMA and performed ICG fluorescence imaging of the blood flow to the sigmoid colon. The postoperative anastomosis-related complications (primary endpoint) and length of viable remnant colon, and the number of lymph nodes retrieved (secondary endpoints) were evaluated and compared with historical controls who underwent conventional IMA-preserving surgery ( n = 20). Results Blood flow reached 40 (17–66) cm retrograde from the peritoneal reflection, even after IMA clamping. Accordingly, IMA high ligation was performed in all cases. No anastomotic anastomosis-related complications occurred in each group. Retrieved total lymph nodes were higher in number in the ICG-guided group than in the conventional group ( p = 0.035). Specifically, more principal nodes were retrieved in the ICG-guided group, compared with the conventional group ( p = 0.023). However, the distal margin was not as long compared with the conventional group. Conclusion We demonstrated the safety and feasibility of high ligation of the IMA for descending colon cancer without sacrificing additional distal colon using fluorescence evaluation of blood flow in the remnant colon.