Abstract
In rectal cancer surgery, in order to identify a tumor site during surgery, preoperative marking using an endoscope, and a method such as the India ink tattooing method is generally performed. However, India ink tattooing causes problems because of adverse events due to India ink leakage into the peritoneal cavity. For preoperative marking of rectal cancer for laparoscopic colorectal surgery, we devised a method of applying the fluorescent properties of indocyanine green（ICG）; here, we report its usefulness. We prospectively evaluated the visibility of the India ink tattooing method compared to the ICG fluorescence method in laparoscopic rectal cancer surgery in which the anal side intestinal tract is dissected below the peritoneal reflection. A total of 18 patients who underwent laparoscopic surgery were enrolled. Study approval was obtained from the Ethics Committee of the Showa University School of Medicine. ICG and India ink were injected into the same patients undergoing preoperative colonoscopy for rectal cancer. Identification of the tumor site during surgery was carried out using the PINPOINT® endoscopic fluorescence imaging system（Novadaq Technologies Inc., Mississauga, Canada）, which was developed by applying the near-infrared fluorescent endoscope imaging system; tumor sites were observed with visible and fluorescent light. The visibility of ICG fluorescence was 88.9％（16/18）, which was significantly better than the visibility of India ink tattooing ［50.0％（9/18）］（p＝0.0293）. The median value of the visibility scale of the tattoo was 0.94（0-2）, the median value of the ICG fluorescence visibility scale was 1.5（0-2）, and the visibility of the ICG fluorescence was significantly higher（p＝0.0370）. Perioperative complications attributed to dye use were not observed. In cases where ICG was not visible, the cause was suspected to be due to the period of local injection, adhesions and mesenteric fat of omentum. Preoperative marking in laparoscopic rectal cancer surgery by the ICG fluorescence method was considered to be a useful alternative to the India ink tattooing.
