Lymph node mapping with near-infrared fluorescence imaging during robotic surgery for gastric cancer: a pilot study

Lymphadenectomy for gastric cancer is considered to be technically difficult to perform in conventional laparoscopic surgery. The robotic system has been introduced to overcome some of these technical limitations of laparoscopy. The daVinci robotic platform allows near-infrared fluorescence imaging (NIFI) with indocyanine green (ICG) to be integrated into the surgical field. This pilot study aimed at investigating whether the use of NIFI with ICG may improve the intraoperative visualization of lymph nodes and help to identify complete lymph node removal during robotic gastrectomy. Fourteen patients underwent robotic distal gastrectomy with D2 lymph node dissection for gastric cancer. A 0.2% ICG solution was injected into the submucosa endoscopically at four sites around the tumor. Fluorescence imaging with ICG was carried out with a robotic infrared camera system. Fluorescent lymph nodes were both dissected out intraoperatively and isolated in the dissected specimen with the help of the robotic camera. Eight males and 6 females were enrolled in the study. No adverse effects of the ICG were observed. The mean total number of examined lymph node was 43.3 (range, 27–78). The mean number of fluorescent lymph nodes was 19.4 (range, 1–36). Seven patients were found to have metastatic lymph nodes: in 3 patients, all the metastatic lymph nodes were fluorescent, in 3 they were non-fluorescent and in 1 patient they were both fluorescent and non-fluorescent. NIFI is a promising method of lymphatic mapping during robotic gastrectomy and may provide a valuable adjunct for identification of complete D2 lymphadenectomy.