[A Case of Rectal Cancer Where the Intestinal Separation Line Was Significantly Altered by the Implementation of Intraoperative ICG Fluorescence Imaging].

ICG fluorescence imaging is a technique used for evaluating blood flow in rectal stumps and can prevent anastomotic insufficiency. An 83-year-old male underwent laparoscopic low anterior resection for rectal cancer. After anal-intestinal tract dissection, we performed an oral-mesenteric division 10 cm above the tumor by extracorporeal operation guided by ICG fluorescence imaging. The blood flow boundary was observed 25 cm from the division site, and no blood flow was detected in the divided section. We performed mesenteric division and dissection at the ICG blood flow boundary. The postoperative course was favorable, and the patient was recurrence-free 1 year later. ICG has become the accepted method of blood flow evaluation and is a valuable tool for the prevention of anastomotic insufficiency. In some cases of rectal cancer, a few reports have shown significantly different results when mesentery division and ICG fluorescence imaging were performed; thus, the outcomes obtained in our case are meaningful.