For identification of segments as fluorescence, ICG (0.025 mg in 10 mL of normal saline) was administered into the portal branch through a needle after its puncture. In contrast, for identification of segments as the defect of fluorescence, ICG (2.5 mg in 1 mL of normal saline) was injected intravenously after clamping of the glissonian pedicle with interest.

Figure 12.3 shows a case of a patient with a colorectal liver metastasis located in segment IV after right hepatectomy. Due to the severe adhesions around the liver and the regeneration of the remnant left liver after previous right hepatectomy, both vascularization in the liver and the tumor-bearing segment were unclear. In order to identify its segment, the suspected portal branch of the tumor-bearing segment was identified by IOUS and punctured with a 22-gauge spinal needle, which was introduced through the abdominal wall and a guide hole on the flexible laparoscopic ultrasonographic probe (BK medical, Herlev, Denmark). After ICG (0.025 mg in 10 mL of normal saline) was administered into the portal branch through the needle, the liver surface corresponding to segment IVb started to fluoresce. The liver surface of the segment IVb provided clear fluorescence less than 5 min after the injection, after which the resection of the anatomical segment IVb was performed (Video 12.3).

Figure 12.4 shows a case of a patient with a colorectal liver metastasis located in segment VI. Anatomical resection of segment VI was attempted to ensure the surgical margin, because intraoperative ultrasound (IOUS) revealed the tumor near from the root of the glissonian pedicle (Fig. 12.4a and Video 12.4). In order to identify the hepatic segment, the glissonian pedicle for segment VI was dissected while using IOUS. After temporarily clamping its root (Fig. 12.4b) and intravenous injection of ICG (2.5 mg), all hepatic segments except for segment VI provides clear fluorescence less than 5 min after injection (Fig. 12.4c). The resection line was marked with ultrasonic laparoscopic coagulation shears (Fig. 12.4d), after which anatomical resection of segment VI was performed. ICG-fluorescence imaging detected no bile leak on the raw surface of the liver after resection (Video 12.4).

These techniques which enable identification of hepatic segments as defect of fluorescence were reported as the positive- or negative-staining technique in authors’ group [8]. The advantage of the negative-staining technique is not technically complicated as compared to the positive-staining technique [8] which requires to perform an image-guided puncture of a portal branch during surgery under laparoscopic control or through abdominal wall before surgery. Although laparoscopic anatomical liver resection is a technically demanding procedure [25], surgeons need to perform it to achieve equivalent oncological outcome for the treatment of hepatocellular carcinoma [26, 27] compared to open hepatectomy. These techniques guide surgeons to clearly identify the hepatic segments before transection of the liver parenchyma, ensuring accurate and efficacious laparoscopic anatomical hepatectomy and probably less postoperative secondary bile leak or abscess due to a devascularized parenchyma in the remnant liver.