**1. Introduction**

For many patients with liver tumours, whether benign or malignant, the optimal form of management is liver surgery. In the modern era with advancement anaesthetic techniques, improved understanding of liver pathophysiology and peri-operative patient management liver surgery has become a safe operation with excellent patient outcomes. Concomitant with this advancement in patient care has been a greater understanding of the nature of liver surgery and improving the precision of liver surgery. In particular surgery has followed the trend in other surgical disciplines and moved towards minimal access surgery. Building on the experiences of laparoscopic liver surgery hepatobiliary surgeons have begun to develop robotic liver surgical programs. Many institutes worldwide have performed complex liver procedures using robot-assisted surgery. This chapter summarises the nascent of field of robotic liver surgery and provides an overview of the current robot technology, surgical techniques and patient outcomes.

### **2. Liver anatomy**

The liver is an accessory digestive gland located in the right upper quadrant of the abdomen. The liver's primary function is to produce bile that aids in the emulsification and digestion of dietary fat. The liver also serves many other critical functions including metabolism of drugs and toxins, removing degradation products of normal body metabolism and synthesis of many important proteins (e.g. clotting factors) and enzymes.

The liver is anatomically divided into two major lobes or into eight segments. Cantile line, which runs from the inferior vena cava (IVC) to the gallbladder fossa, marks the division between the left and right hemi-livers. Each hemi-liver can be divided further anatomically; the left liver can be divided into a left lateral section

#### **Figure 1.**

*The segmental anatomy of the liver. The liver derives its blood supply from the hepatic artery and portal vein. Both divide these structures divide into a left and right vessel to supply the respective side of the liver. The hepatic artery and portal veins divide into segmental branches to supply each of the segments within the liver. Correspondingly each segment has its own biliary duct and venous drainage. Importantly segment 1/caudate lobe is a specialised lobe of the liver and receives blood supply from both the left and right hepatic arteries with biliary drainage to both the left and right biliary ducts. Hence the left liver is made up of the segments 2, 3 and 4 and the right liver of segments 5, 6, 7 and 8.*

(segments 2 and 3) and a left medial section or segment 4. The right hemi-liver can be divided into the right anterior section (segment 5 and 8) and right posterior section (segment 6 and 7). This segmental liver anatomy was originally described by Couinaud and is based upon the eight major divisions of the hepatic artery, portal vein and the biliary system (**Figure 1**). Segment 1 or caudate lobe is a unique liver lobe and is discussed below. Each Couinaud segment has its own arterial and portal blood supply, venous outflow and biliary drainage.

Blood enters the liver from two separate sources. Twenty percent of total liver blood flow is derived from the hepatic artery that is a branch of the coeliac artery. The remaining 80% is derived from the portal vein that is formed by the union of the Superior Mesenteric Vein and Splenic Vein behind the head of the pancreas. This venous blood brings nutrients and oxygen to liver parenchymal cells (e.g. hepatocytes, sinusoidal endothelial cells and cholangiocytes). Venous outflow of the liver is via the hepatic veins, which drain directly into the IVC and then the heart. This basic structure of the liver is integral to the planning of and performance of liver surgery.
