Intraoperative Assessment of the Demarcation Line and Intersegmental/Sectional Planes in Liver Surgery

Abstract

Purpose: Intraoperative assessment of demarcation line (DL) and intersegmental/sectional planes (IP) is essential to perform accurate liver resection without ischemic areas and venous congestion. DL is the most important landmark on the liver surface. The DL is normally formed by means of selective vascular occlusion or portal staining using a dye, and it can be recognized by surgeons’ eye. However, direct visualization with surgeons’ eye suffers from the failing of the evaluation due to an unclear DL, especially in patients with cirrhotic or steatotic livers. Currently, IP, which cannot be recognized by direct visualization, is now in the spotlight during parenchymal transection. Herein, we assessed the DL and IP intraoperatively by several imaging modalities. Method: The DL and IP were intraoperatively detected by means of conventional demarcation techniques and several imaging modalities as follows during liver surgery in a human and an animal model. 1. Direct visualization 2. Indocyanine green fluorescence imaging (ICG-FI) 3. Contrast-enhanced intraoperative ultrasonography (CE-IOUS) 4. Contrast-enhanced intraoperative ultrasonic cholangiography (CE-IOUSC) 5. Augmented Reality using preoperative data (AR) 6. Hyperspectral imaging (HSI) Results: The DL was detected by direct visualization, ICG-FI, and HSI. AR detected virtual DL. On the other hand, the IP was detected by ICG-FI, CE-IOUS, and CE-IOUSC. In this time, we will show the current status and issues with discussion about the strong and weak points of them. Conclusion: New technologies for assessment of DL and IP have a great potential to provide more information to surgeons in order to standardize the surgical approach and develop new surgical approaches.