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Otsuka et al. Hepatoma Res 2021;7:5 I http://dx.doi.org/10.20517/2394-5079.2020.112 Page 13 of 15

Laparoscopic caudal view with magnification can provide a better recognition of structures on hepatic
hilum and dorsal area around the IVC than in the open surgery. Additionally, this approach can be suitable
to maintain liver parenchymal transection plain made along the body axis, such as hemi-hepatectomies.
Therefore, TLHHs can be suitable for technical standardization by laparoscopic procedure. However,
many maneuvers are required to complete the procedures. TLHHs have been suggested as being able to be
accomplished by surgical teams with extensive experiences in both open and laparoscopic liver surgery [10-12] .
Therefore, the maintenance of good operative field with cooperation among the surgeon, assistant, and
scopist is indispensable to standardize the procedures and overcome technical difficulties.

Five trocars with an additional extracorporeal access for Pringle’s maneuver were usually placed in both left
and right hemi-hepatectomies. As mentioned above, our standard formation of the surgeon and assistant
standing on either side of the patient differs from others suggesting that the surgeon stands between the
[11]
patient’s legs .Surgeon use two right-sided trocars of 5mm and 12 mm in diameter, and the assistant uses
trocars from epigastric and left lateral positions. We consider that our preferred formation can significantly
contribute to stable teamwork with the first assistant.

One of the key points is a vascular division on hepatic hilum and major hepatic veins.

In the hilar dissection of TLHHs, we usually used individual vessels isolation technique, the so-called
“control method”, as a conventional intrafascial approach to separate the vessels in the hepato-duodenal
[13]
[14]
ligament . Although the extrafascial Glissonean pedicle approach has also been applied in the hilar
[15]
dissection technique of LH , we prefer the control method because of occasional instability in the
laparoscopic division of Glissonean pedicle by using stapling device due to its thickness and limited
angle, as well as the technical stability of the control method in our team. Here, vessel taping is extremely
important for safe and precise division of the hilar vessels.

The tape retraction of the confluence of hepatic veins to the lateral side is a useful maneuver to apply the
stapling device and divide large hepatic vein safely.

Our timing of liver mobilization differs from other authors, and several approaches to hepatocaval
confluence are described [10,11,16] . When the tumor was not at risk of rupture and the liver parenchyma was
soft, complete mobilization of the liver before parenchymal transection could be performed conventionally.
If operative visualization was suitable, the confluence of right hepatic vein or common confluence of the
middle and left hepatic vein could be encircled extrahepatically. When the isolation of bifurcation of large
hepatic vein and the IVC was complicated, it could be postponed until after liver transection. Whenever
these procedures were performed, the flexible angle laparoscope was an indispensable instrument. For
a large tumor, with or without liver stiffness, anterior approach, which transected the liver prior to liver
mobilization, could be required for the safe manipulation of the liver [16,17] .

We consider that there is no strict distinction in indication of TLHHs for tumor diameter; soft tumors
larger than approximately 70 mm could be removed with conventional fashion, while hard tumors
larger than 70 mm could be better transected by anterior approach. When the tumor was invading the
retroperitoneum, right adrenal gland, or dorsal part of diaphragm, it could also be dissected close to the
end of TLHH procedures, with consideration of requirement of hand-assisted or laparoscopy-assisted
hybrid technique. However, the large tumor which firmly overlays the hepatic hilum is contraindication
of TLHHs. In the retrieval of resected liver, it can be an issue regarding the prolonged operative duration,
putting it into a plastic bag, and removing it from the limited length of skin incision.

Hepatic parenchymal resection should meticulously be performed by using a Cavitron ultrasonic surgical
aspirator or a clamp crushing method under the guidance of intraoperative laparoscopic ultrasound.