To evaluate the application of ICG "four-zone three-phase" fluorescence imaging in robot-assisted anatomical hepatectomy.

Clinical data of 36 patients who underwent robot-assisted anatomical hepatectomy using ICG "four-zone three-phase" fluorescence imaging from January to June 2019 were retrospectively analyzed. The informed consents of all patients were obtained and the local ethical committee approval was received. Among them, 30 patients were male and 6 female, aged (52±9) years on average. Using da Vinci robot-assisted surgery system, the tumor location and size were detected by ICG fluorescence imaging technology combined with intraoperative ultrasound. The liver parenchyma was separated and resected layer-by-layer from bottom to top and front to back by using CUSA, Ligasure and other energy instruments.

All the patients completed robot-assisted anatomical hepatectomy successfully. The median operation time was 130 (30-250) min and intraoperative blood loss was 120(30-350) ml. Intraoperative ICG fluorescence imaging combined with ultrasound found 7 suspicious invisible tumor lesions, of which 3 lesions were diagnosed as hepatocellular carcinoma by intraoperative pathological examination, 3 cirrhosis nodules and 1 inflammatory change. 34 lesions were diagnosed as hepatocellular carcinoma and 2 cholangiocarcinoma by preoperative imaging diagnosis combined with postoperative pathological examination, and all underwent R0 resection. According to ICG fluorescence imaging, the liver was divided into 4 anatomical zones including "tumor zone", "peritumor zone", "ischemia zone" and "reserved liver zone". The normal phase, fluorescence phase and fusion phase of ICG fluorescence imaging could be simultaneously displayed on the main screen by the robot-assisted endoscopic surgery system.

As a real-time intraoperative navigation method, ICG "four-zone three-phase" fluorescence imaging can accurately locate most tumors, clearly display the liver resection plane in a real-time manner and achieve the precision and standardization of anatomical hepatectomy.