A novel endoscopic fluorescent clip visible with near-infrared imaging during laparoscopic surgery in a porcine model

Background: In gastrointestinal cancer surgery, particularly in early cancer, accurate tumor localization is important in order to determine the extent of resection. In laparoscopic surgery, because of the inability to palpate the lesion, the most prevalent method of localization is endoscopic tattooing. However, complicated maneuvering makes it difficult to control local dye spreading and dye leakage into the intraperitoneal cavity. A simpler, safe method is needed. In this study, we developed a novel method for applying fluorescence-coated endoscopic clips to visualize locations inside the colon during laparoscopic surgery. We tested the procedure in an in vivo porcine model and with ex vivo human colon tissues. Methods: Bovine serum albumin was conjugated to indocyanine green or the succinimidyl ester CF™ 790 to form a pasty mixture, which was used to coat the front ends of endoscopic clips. The fluorescence-coated clips were endoscopically placed on the mucosal surface of a porcine colon. Using an Olympus near-infrared laparoscopy system, we attempted to identify the fluorescent clips from the outer, serosal side of the porcine colon during laparoscopic surgery in vivo. The clips were also evaluated using ex vivo human colon tissues. Results: After placing two clips on the inner, mucosal surface of the porcine colon, we used near-infrared laparoscopy to view them from the outer, serosal surface of the colon in real time during in vivo laparoscopic surgery. We also identified the fluorescence-coated clips through human colon tissues in an ex vivo study. Conclusions: We developed a novel, fluorescence-coated clip that can be placed endoscopically for rapid, exact localization of colonic lesions. The clips were successfully visualized with near-infrared fluorescence imaging during laparoscopic surgery in an in vivo porcine model and in ex vivo human colon tissues.