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Page 4 of 7 Kim et al. Hepatoma Res 2021;7:31 https://dx.doi.org/10.20517/2394-5079.2021.09

important determinants of indication for purely laparoscopic isolated caudate lobectomy. Large tumors
located at the Spiegel’s lobe are readily accessible by laparoscopic approach and so are small tumors less
than 5 cm located at the paracaval or at the caudate process. However, tumors larger than 5 cm located at
the paracaval or caudate process would prove to be much more challenging. Theoretically, similar approach
to open surgery such as described by Yamamoto et al. could be feasible but this method has not been
[32]
described yet in the literature and needs to be tested. Furthermore, combined resection of the vena cava is
possible in case the tumor is invaded to or cannot be detached from the IVC and is not an absolute
contraindication. The author has performed a case with partial vena cava resection (unpublished) and there
has been a recent publication that has been performed in a similar fashion by applying laparoscopic vascular
[35]
clamps superior and inferior of the resected IVC by purely laparoscopic method with successful results .
Nevertheless, irrespective of method of approach, we must remember that it is more important to retain
proper oncologic standards rather than be too preoccupied by which approach the operation had been
performed.

Understanding the anatomy is essential and laparoscopic caudate lobectomy is considered to be a difficult
procedure demanding different surgical strategies because of unique anatomy of the caudate lobe.
Nevertheless, laparoscopic approach provides some unique advantages compared to open surgery that
makes laparoscopic approach a much more attractable relative to other lesions located in other segments of
the liver. Traditionally, for open approach, large incision and extensive mobilization are necessary and even
so, visibility remains very limited because of the deep location and its surrounding major vascular
structures. In the contrary, because of its intrinsic “caudal approach” nature in laparoscopic surgery, the
plane lying posteriorly such as between the caudate lobe and the retrohepatic IVC can easily be seen
[36]
through the scope without the need for an extensive dissection . The reverse Trendelenburg position of the
patient further improves exposure by gravitationally shifting visceral structures away from the liver
[29]
hilum . Magnified view shown in high-definition display unit allows clear visualization of the small vessels
and bile ducts often found in caudate lobes and facilitates precision surgery. The flexible scope provides
[21]
various approaching angles which can further improve the quality of the operation . Some have used
infrared indocyanine green fluorescence technology to better visualize the targeted lesion [29,37] .

It is well known that laparoscopic approach reduces bleeding, especially from veins by increasing
intraabdominal pressure during surgery. Estimated blood loss during laparoscopic isolated caudate
lobectomy has not been shown to increase according to previous reports and it can be performed safely
under experienced hands. The presence of pneumoperitoneum provides better bleeding control especially
when working near the IVC and hepatic veins and bleeding control may be done under better
visualization [21,29,38] . For these reasons, the previous comparative study by Xu et al. reported comparable or
[33]
better results in estimated blood loss and operation time compared to those of open caudate lobectomy. The
laparoscopic ultrasonic shear device and the bipolar forceps that have traditionally not been widely used in
open surgery, have been especially useful when dissecting the liver away from the IVC. And lastly, the
resected specimen is usually not large which only requires a small extension of one of the 12 mm port site
incisions to extract the specimen, further adding improved patient recovery and shorter hospital stay.

SURGICAL AND ONCOLOGIC OUTCOMES
Because isolated tumor in caudate lobe is relatively infrequent and caudate lobectomy requires advanced
laparoscopic surgical skills, laparoscopic isolated caudate lobectomy has been mostly reported from high-
volume, experienced centers and data have been limited to case reports or small case series. Despite these
limitations, favorable perioperative outcomes compared to open caudate lobectomy regarding operation
time, intraoperative bleeding, and perioperative morbidity have been reported. However, these results are