Indocyanine green injection for detecting sentinel nodes using color fluorescence camera in the laparoscopy‐assisted gastrectomy

Abstract

We seek for the accurate and simple method for detecting sentinel nodes of gastric cancer which can be popularized in community hospitals. The indocyanine green (ICG) fluorescence-guided method is reported to be sensitive. However, the ordinal fluorescence cameras have gray scale imaging and require a dark room. We have developed a new device, Hyper Eye Medical System (HEMS) which can simultaneously detect color and near-infrared rays and can be used under room light. This study was planned to examine whether submucosal injection of 0.5 mL × 4 of 50 µg/mL ICG on the day before operation is the adequate administration for detecting sentinel nodes using HEMS in the gastric cancer surgery. The patients underwent gastrectomy for clinical T1a (mucosa)-T2 (muscularis propria) and clinical N0 were enrolled in the present study. As a preliminary trial, one case each of the ICG 25 and 100 µg/mL, injected on the day before operation and intraoperative injection, was examined. Then, 10 cases injected 50 µg/mL ICG on the day before operation were examined. The ICG fluorescence of the patient injected 100 µg/mL was too intense and that of the patient injected 25 µg/mL was too faint. Sentinel lymph nodes were detected in all of 10 cases injected 50 µg/mL, the day before operation and number of sentinel lymph nodes per patient was 3.6 ± 2.1. Metastasis was observed in one case. All of ICG fluorescence-positive sentinel nodes were positive for the metastasis. In the patient who underwent intraoperative injection, sentinel lymphatic basins could be identified. The present study shows that HEMS-guided abdominal surgery is feasible under room light. Submucosal injection of 0.5 mL × 4 of 50 µg/mL ICG on the day before operation is the adequate administration for detecting sentinel nodes using HEMS in the gastric cancer surgery.