*5.2.1 Hepato-cystic triangle and Calot's triangle*

The hepato-cystic triangle is the space bordered by the inferior edge of the liver, the common hepatic duct, and the cystic duct of a gallbladder. The cystic artery passes through this space. The Calot's triangle is the bordered by the cystic duct, the cystic artery, and the common hepatic duct. It is important to obtain "the critical view of safety", which first described by Strasberg, et al. to avoid the common bile duct and hepatic duct injury during LC (**Figure 2**) [13].

### **5.3 Surgical procedure**

### *5.3.1 Patient positioning*

The patient is placed in the supine position on the operation table. The operation surgeon stands to the patient's left, scope holder to surgeon's left (British or American style) or between patient's legs (French or European style), and the assistant on the patient's right.

**Figure 2.** *Hepato-cystic triangle and Calot's triangle.*

#### *5.3.2 Port placement and pneumoperitoneum*

The first 12 mm trocar is inserted through 10-15 mm incision through the umbilicus for the development of pneumoperitoneum as well as for the safe insertion of additional trocars under direct laparoscopic vision. Carbon dioxide has been used for the pneumoperitoneum in laparoscopic surgery. Abdominal pressure needs to be adjusted up to obtain adequate working-space, or down to limit the deleterious physiologic effects of the pneumoperitoneum. Abdominal pressure usually adjusts with range from 8 to 12 mmHg, avoiding a pressure about 15 mmHg. After pneumoperitoneum, laparoscope is placed through the umbilical trocar to confirm operative working space and insertion of the accessary trocars under laparoscopic view.

A total of four trocars are essential to perform a cholecystectomy. A trocar of 5 mm for grasping the fundus of the gallbladder is placed in the right anterior axillary line. A second port of 12 mm is placed high in the epigastrium, adjacent to the right of the falciform ligament. The fourth port of 5 mm is placed just below the liver edge in the right midclavicular line.

#### *5.3.3 The dissection of the Calot's triangle*

Dissection of the triangle of Calot's is the dangerous part of the operation. Critical view of safety is the important to avoid misorientation of the anatomy. A surgeon can be certain that cystic duct and cystic artery are identified only by achieving this critical view. Once identification of cystic duct, the duct is dissected only to allow the safe placement of two clips and division. Cystic artery is located cranial to the duct and usually runs paralleled to it. The cystic artery is related posterior to the sentinel lymph node, serving a useful landmark. The right hepatic artery can run very close to the gallbladder and can be easily misoriented for the cystic artery. After division of the cystic duct and artery, the gallbladder is then dissected from the liver bed. Appropriate direct- and counter-traction of gallbladder can help the gallbladder dissect from liver bed. The dissected gallbladder is extracted under direct vision through the umbilical trocar inserted site.
